title: Internal rate of return

text: The method may be applied either ex-post or ex-ante. Applied ex-ante, the IRR is an estimate of a future annual rate of return. Applied ex-post, it measures the actual achieved investment return of a historical investment.


title: Internal rate of return

text: The internal rate of return on an investment or project is the "annualized effective compounded return rate" or rate of return that sets the net present value of all cash flows (both positive and negative) from the investment equal to zero. Equivalently, it is the interest rate at which the net present value of the future cash flows is equal to the initial investment, and it is also the interest rate at which the total present value of costs (negative cash flows) equals the total present value of the benefits (positive cash flows).


title: Internal rate of return

text: IRR accounts for the time preference of money and investments. A given return on investment received at a given time is worth more than the same return received at a later time, so the latter would yield a lower IRR than the former, if all other factors are equal. A fixed income investment in which money is deposited once, interest on this deposit is paid to the investor at a specified interest rate every time period, and the original deposit neither increases nor decreases, would have an IRR equal to the specified interest rate. An investment which has the same total returns as the preceding investment, but delays returns for one or more time periods, would have a lower IRR.


title: Internal rate of return

text: The internal rate of return is an indicator of the profitability, efficiency, quality, or yield of an investment. This is in contrast with the net present value, which is an indicator of the net value or magnitude added by making an investment.


title: Internal rate of return

text: To maximize the value of a business, an investment should be made only if its profitability, as measured by the internal rate of return, is greater than a minimum acceptable rate of return. If the estimated IRR of a project or investment - for example, the construction of a new factory - exceeds the firm's cost of capital invested in that project, the investment is profitable. If the estimated IRR is less than the cost of capital, the proposed project should not be undertaken.


title: Internal rate of return

text: The selection of investments may be subject to budget constraints. There may be mutually exclusive competing projects, or limits on a firm's ability to manage multiple projects. For these reasons, corporations use IRR in capital budgeting to compare the profitability of a set of alternative capital projects. For example, a corporation will compare an investment in a new plant versus an extension of an existing plant based on the IRR of each project. To maximize returns, the higher a project's IRR, the more desirable it is to undertake the project.


title: Internal rate of return

text: There are at least two different ways to measure the IRR for an investment: the project IRR and the equity IRR. The project IRR assumes that the cash flows directly benefit the project, whereas equity IRR considers the returns for the shareholders of the company after the debt has been serviced.


title: Internal rate of return

text: Even though IRR is one of the most popular metrics used to test the viability of an investment and compare returns of alternative projects, looking at the IRR in isolation might not be the best approach for an investment decision. Certain assumptions made during IRR calculations are not always applicable to the investment. In particular, IRR assumes that the project will have either no interim cash flows or the interim cash flows are reinvested into the project which is not always the case. This discrepancy leads to overestimation of the rate of return which might be an incorrect representation of the value of the project.


title: Internal rate of return

text: The internal rate of return is used to evaluate investments in fixed income securities, using metrics such as the yield to maturity and yield to call.


title: Internal rate of return

text: Both the internal rate of return and the net present value can be applied to liabilities as well as investments. For a liability, a lower internal rate of return is preferable to a higher one.


title: Internal rate of return

text: Corporations use internal rate of return to evaluate share issues and stock buyback programs. A share repurchase proceeds if returning capital to shareholders has a higher internal rate of return than candidate capital investment projects or acquisition projects at current market prices. Funding new projects by raising new debt may also involve measuring the cost of the new debt in terms of the yield to maturity (internal rate of return).


title: Internal rate of return

text: IRR is also used for private equity, from the limited partners' perspective, as a measure of the general partner's performance as investment manager. This is because it is the general partner who controls the cash flows, including the limited partners' draw-downs of committed capital.


title: Internal rate of return

text: Given a collection of pairs (time, cash flow) representing a project, the net present value is a function of the rate of return. The internal rate of return is a rate for which this function is zero, i.e. the internal rate of return is a solution to the equation NPV = 0 (assuming no arbitrage conditions exist).


title: Internal rate of return

text: Given the (period, cash flow) pairs (formula_1, formula_2) where formula_1 is a non-negative integer, the total number of periods formula_4, and the formula_5, (net present value); the internal rate of return is given by formula_6 in:


title: Internal rate of return

text: This rational polynomial can be converted to an ordinary polynomial having the same roots by substituting "g" (gain) for formula_8 and multiplying by formula_9 to yield the equivalent but simpler condition


title: Internal rate of return

text: The possible IRR's are the real values of "r" satisfying the first condition, and 1 less than the real roots of the second condition (that is, formula_11 for each root "g"). Note that in both formulas, formula_12 is the negation of the initial investment at the start of the project while formula_13 is the cash value of the project at the end, equivalently the cash withdrawn if the project were to be liquidated and paid out so as to reduce the value of the project to zero. In the second condition formula_12 is the leading coefficient of the ordinary polynomial in "g" while formula_13 is the constant term.


title: Internal rate of return

text: The period formula_1 is usually given in years, but the calculation may be made simpler if formula_6 is calculated using the period in which the majority of the problem is defined (e.g., using months if most of the cash flows occur at monthly intervals) and converted to a yearly period thereafter.


title: Internal rate of return

text: Any fixed time can be used in place of the present (e.g., the end of one interval of an annuity); the value obtained is zero if and only if the NPV is zero.


title: Internal rate of return

text: In the case that the cash flows are random variables, such as in the case of a life annuity, the expected values are put into the above formula.


title: Internal rate of return

text: Often, the value of formula_6 that satisfies the above equation cannot be found analytically. In this case, numerical methods or graphical methods must be used.


title: Internal rate of return

text: Since the above is a manifestation of the general problem of finding the roots of the equation formula_21, there are many numerical methods that can be used to estimate formula_6. For example, using the secant method, formula_6 is given by


title: Internal rate of return

text: This formula_6 can be found to an arbitrary degree of accuracy. Different accounting packages may provide functions for different accuracy levels. For example, Microsoft Excel and Google Sheets have built-in functions to calculate IRR for both fixed and variable time-intervals; "=IRR(...)" and "=XIRR(...)".


title: Internal rate of return

text: Having formula_35 when formula_36 or formula_37 when formula_38 may speed up convergence of formula_25 to formula_6.


title: Internal rate of return

text: Of particular interest is the case where the stream of payments consists of a single outflow, followed by multiple inflows occurring at equal periods. In the above notation, this corresponds to:


title: Internal rate of return

text: In this case the NPV of the payment stream is a convex, strictly decreasing function of interest rate. There is always a single unique solution for IRR.


title: Internal rate of return

text: Given two estimates formula_42 and formula_43 for IRR, the secant method equation (see above) with formula_44 always produces an improved estimate formula_45. This is sometimes referred to as the Hit and Trial (or Trial and Error) method. More accurate interpolation formulas can also be obtained: for instance the secant formula with correction


title: Internal rate of return

text: (which is most accurate when formula_47) has been shown to be almost 10 times more accurate than the secant formula for a wide range of interest rates and initial guesses. For example, using the stream of payments {−4000, 1200, 1410, 1875, 1050} and initial guesses formula_48 and formula_49 the secant formula with correction gives an IRR estimate of 14.2% (0.7% error) as compared to IRR = 13.2% (7% error) from the secant method.


title: Internal rate of return

text: If applied iteratively, either the secant method or the improved formula always converges to the correct solution.


title: Internal rate of return

text: Both the secant method and the improved formula rely on initial guesses for IRR. The following initial guesses may be used:


title: Internal rate of return

text: A cash flow formula_2 may occur at any time formula_57 years after the beginning of the project. formula_57 may not be a whole number. The cash flow should still be discounted by a factor formula_59. And the formula is


title: Internal rate of return

text: As a tool applied to making an investment decision on whether a project adds value or not, comparing the IRR of a single project with the required rate of return, in isolation from any other projects, is equivalent to the NPV method. If the appropriate IRR (if such can be found correctly) is greater than the required rate of return, using the required rate of return to discount cash flows to their present value, the NPV of that project will be positive, and vice versa. However, using IRR to sort projects in order of preference does not result in the same order as using NPV.


title: Internal rate of return

text: When the objective is to maximize total value, the calculated IRR should not be used to choose between mutually exclusive projects. In cases where one project has a higher initial investment than a second mutually exclusive project, the first project may have a lower IRR (expected return), but a higher NPV (increase in shareholders' wealth) and should thus be accepted over the second project (assuming no capital constraints).


title: Internal rate of return

text: When the objective is to maximize total value, IRR should not be used to compare projects of different duration. For example, the net present value added by a project with longer duration but lower IRR could be greater than that of a project of similar size, in terms of total net cash flows, but with shorter duration and higher IRR.


title: Internal rate of return

text: Despite a strong academic preference for net present value, surveys indicate that executives prefer IRR over NPV. Apparently, managers prefer to compare investments of different sizes in terms of forecast investment performance, using IRR, rather than maximize value to the firm, in terms of NPV. This preference makes a difference when comparing mutually exclusive projects.


title: Internal rate of return

text: Maximizing total value is not the only conceivable possible investment objective. An alternative objective would for example be to maximize long-term return. Such an objective would rationally lead to accepting first those new projects within the capital budget which have the highest IRR, because adding such projects would tend to maximize overall long-term return.


title: Internal rate of return

text: To see this, consider two investors, Max Value and Max Return. Max Value wishes her net worth to grow as large as possible, and will invest every last cent available to achieve this, whereas Max Return wants to maximize his rate of return over the long term, and would prefer to choose projects with smaller capital outlay but higher returns. Max Value and Max Return can each raise "up to" 100,000 US dollars from their bank at an annual interest rate of 10 percent paid at the end of the year.


title: Internal rate of return

text: Investors Max Value and Max Return are presented with two possible projects to invest in, called Big-Is-Best and Small-Is-Beautiful. Big-Is-Best requires a capital investment of 100,000 US dollars today, and the lucky investor will be repaid 132,000 US dollars in a year's time. Small-Is-Beautiful only requires 10,000 US dollars capital to be invested today, and will repay the investor 13,750 US dollars in a year's time.


title: Internal rate of return

text: Both investments would be acceptable to both investors, but the twist in the tale is that these are mutually exclusive projects for both investors, because their capital budget is limited to 100,000 US dollars. How will the investors choose rationally between the two?


title: Internal rate of return

text: The happy outcome is that Max Value chooses Big-Is-Best, which has the higher NPV of 20,000 US dollars, over Small-Is-Beautiful, which only has a modest NPV of 2,500, whereas Max Return chooses Small-Is-Beautiful, for its superior 37.5 percent return, over the attractive (but not as attractive) return of 32 percent offered on Big-Is-Best. So there is no squabbling over who gets which project, they are each happy to choose different projects.


title: Internal rate of return

text: How can this be rational for both investors? The answer lies in the fact that the investors do not have to invest the full 100,000 US dollars. Max Return is content to invest only 10,000 US dollars for now. After all, Max Return may rationalize the outcome by thinking that maybe tomorrow there will be new opportunities available to invest the remaining 90,000 US dollars the bank is willing to lend Max Return, at even higher IRRs. Even if only seven more projects come along which are identical to Small-Is-Beautiful, Max Return would be able to match the NPV of Big-Is-Best, on a total investment of only 80,000 US dollars, with 20,000 US dollars left in the budget to spare for truly unmissable opportunities. Max Value is also happy, because she has filled her capital budget straight away, and decides she can take the rest of the year off investing.


title: Internal rate of return

text: When the sign of the cash flows changes more than once, for example when positive cash flows are followed by negative ones and then by positive ones (+ + − − − +), the IRR may have multiple real values. In a series of cash flows like (−10, 21, −11), one initially invests money, so a high rate of return is best, but then receives more than one possesses, so then one owes money, so now a low rate of return is best. In this case, it is not even clear whether a high or a low IRR is better.


title: Internal rate of return

text: There may even be multiple real IRRs for a single project, like in the example 0% as well as 10%. Examples of this type of project are strip mines and nuclear power plants, where there is usually a large cash outflow at the end of the project.


title: Internal rate of return

text: The IRR satisfies a polynomial equation. Sturm's theorem can be used to determine if that equation has a unique real solution. In general the IRR equation cannot be solved analytically but only by iteration.


title: Internal rate of return

text: With multiple internal rates of return, the IRR approach can still be interpreted in a way that is consistent with the present value approach if the underlying investment stream is correctly identified as net investment or net borrowing.


title: Internal rate of return

text: In the context of survivorship bias which makes the high IRR of large private equity firms a poor representation of the average, according to Ludovic Phalippou,


title: Internal rate of return

text: "...a headline figure that is often shown prominently as a rate of return in presentations and documents is, in fact, an IRR. IRRs are not rates of return. Something large PE firms have in common is that their early investments did well. These early winners have set up those firms' since-inception IRR at an artificially sticky and high level. The mathematics of IRR means that their IRRs will stay at this level forever, as long as the firms avoid major disasters. In passing, this generates some stark injustice because it is easier to game IRRs on LBOs in Western countries than in any other PE investments. That means that the rest of the PE industry (e.g. emerging market growth capital) is sentenced to look relatively bad forever, for no reason other than the use of a game-able performance metric."


title: Internal rate of return

text: "Another problem with the presentation of pension fund performance is that for PE, time-weighted returns...are not the most pertinent measure of performance. Asking how much pension funds gave and got back in dollar terms from PE, i.e. MoM, would be more pertinent. I went through the largest 15 funds websites to collect information on their performance. Few of them post their PE fund returns online. In most cases, they post information on their past performance in PE, but nothing that enables any meaningful benchmarking. "E.g.", CalSTRS [a California public pension fund] provide only the net IRR for each fund they invest in. As IRR is often misleading and can never be aggregated or compared to stock-market returns, such information is basically useless for gauging performance."


title: Internal rate of return

text: Modified Internal Rate of Return (MIRR) considers cost of capital, and is intended to provide a better indication of a project's probable return. It applies a discount rate for borrowing cash, and the IRR is calculated for the investment cash flows. This applies in real life for example when a customer makes a deposit before a specific machine is built.


title: Internal rate of return

text: When a project has multiple IRRs it may be more convenient to compute the IRR of the project with the benefits reinvested. Accordingly, MIRR is used, which has an assumed reinvestment rate, usually equal to the project's cost of capital.


title: Internal rate of return

text: Magni (2010) introduced a new approach, named AIRR approach, based on the intuitive notion of mean, that solves the problems of the IRR. However, the above-mentioned difficulties are only some of the many flaws incurred by the IRR. Magni (2013) provided a detailed list of 18 flaws of the IRR and showed how the AIRR approach does not incur the IRR problems.


title: Internal rate of return

text: Mathematically, the value of the investment is assumed to undergo exponential growth or decay according to some rate of return (any value greater than −100%), with discontinuities for cash flows, and the IRR of a series of cash flows is defined as any rate of return that results in a net present value of zero (or equivalently, a rate of return that results in the correct value of zero after the last cash flow).


title: Internal rate of return

text: Thus, internal rate(s) of return follow from the net present value as a function of the rate of return. This function is continuous. Towards a rate of return of −100% the net present value approaches infinity with the sign of the last cash flow, and towards a rate of return of positive infinity the net present value approaches the first cash flow (the one at the present). Therefore, if the first and last cash flow have a different sign there exists an internal rate of return. Examples of time series without an IRR:


title: Internal rate of return

text: In the case of a series of exclusively negative cash flows followed by a series of exclusively positive ones, the resulting function of the rate of return is continuous and monotonically decreasing from positive infinity (when the rate of return approaches -100%) to the value of the first cash flow (when the rate of return approaches infinity), so there is a unique rate of return for which it is zero. Hence, the IRR is also unique (and equal). Although the NPV-function itself is not necessarily monotonically decreasing on its whole domain, it "is" at the IRR.


title: Internal rate of return

text: Similarly, in the case of a series of exclusively positive cash flows followed by a series of exclusively negative ones the IRR is also unique.


title: Internal rate of return

text: Finally, by Descartes' rule of signs, the number of internal rates of return can never be more than the number of changes in sign of cash flow.


title: Internal rate of return

text: It is often stated that IRR assumes reinvestment of all cash flows until the very end of the project. This assertion has been a matter of debate in the literature.


title: Internal rate of return

text: Sources stating that there is such a hidden assumption have been cited below. Other sources have argued that there is no IRR reinvestment assumption.


title: Internal rate of return

text: When comparing investments, making an implicit assumption that cash flows are reinvested at the same IRR would lead to false conclusions. If cash flows received are not reinvested at the same rate as the IRR, a project with a relatively short duration and a high IRR does not necessarily add more value over a longer time span than another project with a longer duration and a lower IRR. This is why IRR should not be used on a stand-alone basis, but in combination with NPV.


title: Internal rate of return

text: The Modified Internal Rate of Return (MIRR) addresses this issue by allowing for the inclusion a second investment at a potentially different rate of return, to calculate a portfolio return without external cash flows over the life of the project. However, for capital budgeting, when the objective is to maximize value, finance theory holds that NPV using the firm's cost of capital is the optimal metric.


title: Internal rate of return

text: more intuitive definition of the IRR is, "The IRR is the annual interest rate of the fixed rate account (like a somewhat idealized savings account)


title: Internal rate of return

text: which, when subjected to the same deposits and withdrawals as the actual investment, has the same ending balance as the actual investment."


title: Internal rate of return

text: This fixed rate account is also called the "replicating fixed rate account" for the investment. There are examples where


title: Internal rate of return

text: the replicating fixed rate account encounters negative balances despite the fact that the actual investment did not.


title: Internal rate of return

text: In those cases, the IRR calculation assumes that the same interest rate that is paid on positive balances is charged on


title: Internal rate of return

text: negative balances. It has been shown that this way of charging interest is the root cause of the IRR's multiple solutions


title: Internal rate of return

text: problem. If the model is modified so that, as is the case in real life, an externally supplied cost of borrowing


title: Internal rate of return

text: In the context of investment performance measurement, there is sometimes ambiguity in terminology between the periodic rate of return, such as the internal rate of return as defined above, and a holding period return. The term "internal rate of return" or "IRR" or "Since Inception Internal Rate of Return (SI-IRR)" is in some contexts used to refer to the unannualized return over the period, particularly for periods of less than a year.


title: Dinosaurs in Jurassic Park

text: "Jurassic Park", later known as "Jurassic World", is an American science fiction adventure media franchise. It focuses on the cloning of dinosaurs through ancient DNA, extracted from mosquitoes that have been fossilized in amber. The franchise explores the ethics of cloning and genetic engineering, and the morals behind de-extinction.


title: Dinosaurs in Jurassic Park

text: The franchise began in 1990, with the release of Michael Crichton's novel "Jurassic Park". A film adaptation, also titled "Jurassic Park", was directed by Steven Spielberg and was released in 1993. Crichton then wrote a sequel novel, "The Lost World" (1995), and Spielberg directed its film adaptation, "" (1997). Subsequent films have been released, including "Jurassic Park III" in 2001, completing the original trilogy of films. A fourth installment, "Jurassic World", was released in 2015, marking the beginning of a new trilogy. Its sequel, "", was released in 2018. A sixth film, "Jurassic World Dominion", released in 2022, marks the conclusion of the second trilogy. Two "Jurassic World" short films have also been released: "Battle at Big Rock" (2019) and a "Jurassic World Dominion" prologue (2021).


title: Dinosaurs in Jurassic Park

text: Theropod dinosaurs like "Tyrannosaurus rex" and "Velociraptor" have had major roles throughout the film series. Other species, including "Brachiosaurus" and "Spinosaurus", have also played significant roles. The series has also featured other creatures such as "Mosasaurus" and members of the pterosaur group, both commonly misidentified by the public as dinosaurs. The various creatures in the films were created through a combination of animatronics and computer-generated imagery (CGI). For the first three films, the animatronics were created by special-effects artist Stan Winston and his team, while Industrial Light & Magic (ILM) handled the CGI for all the films. The first film garnered critical acclaim for its innovations in CGI technology and animatronics. Since Winston's death in 2008, the practical dinosaurs have been created by other artists, including Legacy Effects and Image Engine ("Jurassic World"), Neal Scanlan ("Jurassic World: Fallen Kingdom"), and John Nolan ("Jurassic World Dominion").


title: Dinosaurs in Jurassic Park

text: Paleontologist Jack Horner has served as the longtime scientific advisor on the films, and paleontologist Steve Brusatte was also consulted for "Jurassic World Dominion". The original film was praised for its modern portrayal of dinosaurs. Horner said that it still contained many inaccuracies, but noted that it was not meant as a documentary. Later films in the series contain inaccuracies as well, for entertainment purposes. This includes the films' velociraptors, which are depicted as being larger than their real-life counterparts. In addition, the franchise's method for cloning dinosaurs has been deemed scientifically implausible, for a number of reasons.


title: Dinosaurs in Jurassic Park

text: The various creatures in the "Jurassic Park" and "Jurassic World" films were created through a combination of animatronics and computer-generated imagery (CGI). For each of the films, Industrial Light & Magic (ILM) has handled dinosaur scenes that required CGI. Throughout the film series, ILM has studied large animals such as elephants and rhinos, for reference in designing the digital dinosaurs.


title: Dinosaurs in Jurassic Park

text: For the original 1993 film "Jurassic Park", director Steven Spielberg wanted to use practical dinosaurs as much as possible. He chose special-effects artist Stan Winston to create animatronic dinosaurs for the film, after seeing his work on the Queen Alien in the 1986 film "Aliens". Winston said the Queen was easy compared to a dinosaur animatronic: "The queen was exoskeletal, so all of its surfaces were hard. There were no muscles, no flesh, and there was no real weight to it. The alien queen also didn't have to look like a real, organic animal because it was a fictional character -- so there was nothing in real life to compare it to. There was just no comparison in the difficulty level of building that alien queen and building a full-size dinosaur". Winston's team spent much time perfecting the animatronics, which used metal skeletons powered by electric motors. They molded latex skin that was then fitted over the robotic models, forming the exterior appearance. Up to 20 puppeteers were required to operate some of the dinosaurs. After filming concluded, most of the animatronics were disassembled.


title: Dinosaurs in Jurassic Park

text: For certain scenes, Spielberg had considered using go motion dinosaurs created by visual-effects artist Phil Tippett. Spielberg was disappointed with the results and opted for ILM's digital dinosaurs instead, although Tippett and his team of animators remained with the project to supervise the dinosaur movements. Tippett and ILM worked together to create the Dinosaur Input Device (DID), a robot shaped like a dinosaur skeleton. The DID included an array of sensors that captured various poses, which were then transferred into graphics software at ILM. Animatics and storyboards by Tippett were also used by the film crew as reference for action sequences. ILM based their CGI dinosaurs on Winston's models. Herds of dinosaurs were created through computer animation, using duplicate individuals which were slightly altered to give the illusion of multiple animals. The 127-minute film has 15 minutes of total screen time for the dinosaurs, including nine minutes of animatronics and six minutes of CGI animals. The film received critical acclaim for its innovations in CGI technology and animatronics. Among adults, the film generated an interest in dinosaurs, and it increased interest in the field of paleontology.


title: Dinosaurs in Jurassic Park

text: Winston and his team returned for the 1997 sequel, "", although the film relied more on CGI by ILM. The film features 75 computer-generated shots. While the first film showed that dinosaurs could be adequately recreated through special effects, the sequel raised the question of what could be done with the dinosaurs. Winston said, "I wanted to show the world what they didn't see in 'Jurassic Park': more dinosaurs and more dinosaur action. 'More, bigger, better' was our motto". Technology had not advanced much since the first film, although director Spielberg said that "the artistry of the creative computer people" had advanced: "There's better detail, much better lighting, better muscle tone and movement in the animals. When a dinosaur transfers weight from his left side to his right, the whole movement of fat and sinew is smoother, more physiologically correct". Besides animatronics, Winston's team also painted maquettes of dinosaurs that would subsequently be created through CGI.


title: Dinosaurs in Jurassic Park

text: Spielberg served as executive producer for each subsequent film. ILM and Winston returned for the 2001 film "Jurassic Park III", directed by Joe Johnston. Winston's animatronics were more advanced than those used in previous films; they included the ability to blink, adding to the sense of realism. Animatronics were used for close-up shots. Winston's team took approximately 13 months to design and create the practical dinosaurs. The team also created dinosaur sculptures, which were then scanned by ILM to create the computer-generated versions of the animals.


title: Dinosaurs in Jurassic Park

text: Winston planned to return for a fourth film, which was ultimately released in 2015 as "Jurassic World". Winston, who had been planning more-advanced special effects for the project, died in 2008 before the start of filming. Legacy Effects, founded by former members of Stan Winston Studios, provided an animatronic dinosaur for "Jurassic World". Otherwise, the film's creatures were largely created through CGI, provided by ILM and Image Engine. New technology, such as subsurface scattering, allowed for greater detail in the creatures' skin and muscle tissue. According to "Jurassic World" director Colin Trevorrow, the film's animals were created from scratch because "technology has changed so much that everything is a rebuild". Some of the computer-generated creatures were created with motion capture, using human actors to perform the animals' movements. "Jurassic World" was the first dinosaur film to use motion capture technology.


title: Dinosaurs in Jurassic Park

text: ILM returned for the 2018 sequel, "", which featured animatronics by special-effects artist Neal Scanlan. The film features more dinosaurs than any previous film, including several new ones not seen in earlier films. "Jurassic World: Fallen Kingdom" also features more animatronic dinosaurs than any previous sequel, and the animatronics used were more advanced than in previous films. "Fallen Kingdom" director J.A. Bayona said animatronics "are very helpful on set, especially for the actors so they have something to perform against. There's an extra excitement if they can act in front of something real".


title: Dinosaurs in Jurassic Park

text: Five animatronic dinosaurs were created for "Fallen Kingdom", which features close interaction between humans and dinosaurs. Scanlan and his team of 35 people spent more than eight months working on the dinosaurs. Scanlan said animatronics were not best for every scene: "In some ways it will have an impact on your shooting schedule; you have to take time to film with an animatronic. In the balance, we ask ourselves if it is economically and artistically more valuable to do it that way, or as a post-production effect". Unlike the previous film, ILM determined that motion capture technology would not be adequate for depicting the film's dinosaurs.


title: Dinosaurs in Jurassic Park

text: The 2019 "Jurassic World" short film, "Battle at Big Rock", utilized CGI and reference maquettes by ILM, and an animatronic by Legacy Effects.


title: Dinosaurs in Jurassic Park

text: The 2022 film "Jurassic World Dominion" used more animatronics than the previous "Jurassic World" films. Approximately 18 animatronics of varying sizes were created for the film, by designer John Nolan. In a departure from previous films, the dinosaurs were made of recyclable materials. ILM created 900 CGI dinosaur shots for the film, and also produced various CGI dinosaurs for the film's five-minute prologue, released in 2021.


title: Dinosaurs in Jurassic Park

text: The franchise's premise involves the cloning of dinosaurs through ancient DNA, extracted from mosquitoes that sucked the blood of such animals and were then fossilized in amber, preserving the DNA. Later research showed that this would not be possible due to the degradation of DNA over time. The oldest DNA ever found only dated back approximately 1 million years, whereas dinosaurs died 66 million years ago. It is also unlikely that dinosaur DNA would survive a mosquito's digestive process, and fragments of DNA would not be nearly enough to recreate a dinosaur. In addition, the type of mosquito used in the first film, "Toxorhynchites rutilus", does not actually suck blood.


title: Dinosaurs in Jurassic Park

text: The premise presents other issues as well. Michael Crichton's 1990 novel "Jurassic Park" and its film adaptation both explain that gene sequence gaps were filled in with frog DNA, although this would not result in a true dinosaur, as frogs and dinosaurs are not genetically similar. Furthermore, the novel uses artificial eggs to grow the dinosaurs, while the film uses ostrich eggs, although neither would be suitable for development. In addition, dinosaurs would likely have trouble adapting to the modern world, in part because of different oxygen levels.


title: Dinosaurs in Jurassic Park

text: At the time of the first film's release, Spielberg said he considered the premise to be "science eventuality" rather than science fiction, although Crichton disagreed: "It never crossed my mind that it was possible. From the first moment of publication, I was astonished by the degree to which it was taken seriously in scientific circles". Microbiologists at the time considered the premise to be implausible. The film's dinosaur consultant, paleontologist Jack Horner, later said: "Even if we had dinosaur DNA, we don't know how to actually form an animal just from DNA. The animal cloning that we do these days is with a live cell. We don't have any dinosaur live cells. The whole business of having a dinosaur is a lot of fiction". Horner has instead proposed that a "Chickenosaurus" may be possible, by altering a chicken's DNA.


title: Dinosaurs in Jurassic Park

text: In creating "Jurassic Park", Spielberg wanted to accurately portray the dinosaurs, and Horner was hired to ensure such accuracy. Tippett, a dinosaur enthusiast, also helped to keep the dinosaur portrayals realistic. The film followed the theory that dinosaurs had evolved into birds, and it was praised for its modern portrayal of dinosaurs, although Horner said that there were still many inaccuracies. However, he noted that the film is not a documentary and said he was "happy with having some fiction thrown in", stating: "My job was to get a little science into "Jurassic Park", but not ruin it". Spielberg sought to portray the dinosaurs as animals rather than monsters, which changed the public perception of dinosaurs, although the sequels would have a deeper focus on rampaging dinosaurs. Horner said that in reality, "visiting a dinosaur park would be like going to a wild animal park. As long as you keep your windows rolled up, nobody's going to bother you. But that doesn't make a very good movie".


title: Dinosaurs in Jurassic Park

text: Horner was involved throughout the production process. His consulting work included the supervision of the CGI dinosaurs, ensuring that they were life-like and scientifically accurate. Horner and Spielberg would discuss ways to combine scientific facts with fictional elements, the latter being for entertainment purposes. Horner said "if I could demonstrate that something was true or not true, then he would go with that, but if I had some question about it and we didn't really have much evidence about it, he would go with whatever he thought would make the best movie". Horner returned as a paleontological consultant for the next four films. For "The Lost World: Jurassic Park", Spielberg largely followed Horner's advice regarding dinosaur accuracy, but some exceptions were made. Winston's team closely modelled the dinosaurs based on paleontological facts, or theories in certain cases where facts were not definitively known. In "Jurassic Park III", the character Dr. Alan Grant, a paleontologist, states that the resurrected dinosaurs are not authentic but rather are "genetically engineered theme park monsters". The film introduces a "Velociraptor" design featuring quills along the head. Aside from this, feathered dinosaurs have largely been absent from the series.


title: Dinosaurs in Jurassic Park

text: Before the release of "Jurassic World", new research had shown that real dinosaurs were more colorful than they were in the films. Horner said that Spielberg "has made the point several times to me that colorful dinosaurs are not very scary. Gray and brown and black are more scary". Horner considered the colors to be the most inaccurate aspect of the films' dinosaurs. In addition, the dinosaurs are often depicting roaring, although paleontologists find this speculative or unrealistic. Horner said: "Dinosaurs gave rise to birds, and birds sing. I think most of the dinosaurs actually sang rather than growled".


title: Dinosaurs in Jurassic Park

text: Despite new dinosaur discoveries, the sequels largely kept the earlier dinosaur designs for continuity with the previous films. Paleontologists were disappointed with the outdated dinosaur portrayals in "Jurassic World", including the lack of feathered dinosaurs, although they acknowledged that it is a work of fiction. Trevorrow said that "Jurassic World" was not meant as a documentary film, but as a sci-fi film. The film itself includes a scene stating that any inaccuracies in the dinosaurs can be attributed to the fact that they are genetically engineered animals. Trevorrow noted that the dinosaurs in the franchise – going back to Crichton's novels "Jurassic Park" and "The Lost World" (1995) – were partially recreated with frog DNA, stating "those weren't 'real' dinosaurs, any of them". Tim Alexander, visual effects supervisor for ILM, said that colorful dinosaurs were excluded because they would look out of place in the film: "It's very forest greens and taupes and park rangers. And if we then throw a bright pink raptor in there, it's going to stick out and look a little weird".


title: Dinosaurs in Jurassic Park

text: For "Jurassic World: Fallen Kingdom", ILM consulted with paleontologists and did extensive research to accurately depict the dinosaurs. Dinosaur expert John Hankla, of the Denver Museum of Nature and Science, served as an advisor on the film, and also provided several dinosaur fossil recreations for the film. Horner said that his own involvement on "Fallen Kingdom" was minimal. Horner was consulted again for "Jurassic World Dominion", and paleontologist Steve Brusatte was also hired as a science consultant. Fully feathered dinosaurs are introduced in "Jurassic World Dominion" and its prologue.


title: Dinosaurs in Jurassic Park

text: The following list includes on-screen appearances. Some animals listed here have also made prior appearances in the novels.


title: Dinosaurs in Jurassic Park

text: "Ankylosaurus" first appears in "Jurassic Park III", through brief appearances. It was created by ILM entirely through CGI.


title: Dinosaurs in Jurassic Park

text: "Ankylosaurus" also appears in "Jurassic World", as Trevorrow considered the dinosaur to be among his favorites. It is one of several creatures that Trevorrow felt was deserving of a substantial scene. In the film, an "Ankylosaurus" is killed by the "Indominus rex". Trevorrow stated that the dinosaur's death was an example of moments in the film "that are designed to really make these creatures feel like living animals that you can connect to. Especially since so many of the themes in the film involve our relationship with animals on the planet right now, I wanted them to feel real".


title: Dinosaurs in Jurassic Park

text: In "Jurassic World: Fallen Kingdom", several "Ankylosaurus" flee from a volcanic eruption and at least one is captured by mercenaries. It is later auctioned off to a wealthy Indonesian. Several "Ankylosaurus" escaped the Lockwood Manor Estate grounds alongside the other dinosaurs.


title: Dinosaurs in Jurassic Park

text: In the novel "Jurassic Park", "Apatosaurus" is the first group of dinosaurs seen on the island. It is replaced by "Brachiosaurus" in the film adaptation. "Apatosaurus" also appears in the sequel novel "The Lost World", but is absent from its film adaptation.


title: Dinosaurs in Jurassic Park

text: "Apatosaurus" makes its first film appearance in "Jurassic World", with several individuals being featured, including one depicted by an animatronic. Unlike earlier films which featured numerous animatronics, the "Apatosaurus" was the only one created for "Jurassic World". Producer Patrick Crowley was initially hesitant to have an animatronic built because of the high cost, but Trevorrow persuaded him that fans of the series would enjoy it. The animatronic, built by Legacy Effects, consisted of a -long section of the dinosaur's neck and head. It was used for a close-up shot depicting the animal's death, after it had been injured in a dinosaur attack. Audio recordings of a Harris's hawk were used for the moans of the wounded "Apatosaurus".


title: Dinosaurs in Jurassic Park

text: To animate the "Apatosaurus", ILM used elephants as an example. Glen McIntosh, the animation supervisor for ILM, stated that "there are no existing animals that have such large necks, but in terms of the size and steps they're taking, elephants are an excellent example of that. Also the way their skin jiggles and sags. You also have impact tremors that rise up through their legs as they take steps". Originally, Legacy Effects only created a small model of the "Apatosaurus" for use in the film, but executive producer Steven Spielberg decided that a larger model would be better. The original model was scanned into a computer, allowing artists to create a larger 3-D model needed for the film. "Apatosaurus" makes appearances in the subsequent "Jurassic World" films.


title: Dinosaurs in Jurassic Park

text: In the first "Jurassic Park" film, a "Brachiosaurus" is the first dinosaur seen by the park's visitors. The scene was described by "Empire" as the 28th most magical moment in cinema. A later scene depicts characters in a high tree, interacting with a "Brachiosaurus". This scene required the construction of a -tall puppet that represented the animal's upper neck and head. The film inaccurately depicts the species as having the ability to stand on its hind legs, allowing it to reach high tree branches. The dinosaur is also inaccurately depicted as chewing its food, an idea that was added to make it seem docile like a cow. Whale songs and donkey calls were used for the "Brachiosaurus" sounds, although scientific evidence showed that the real animal had limited vocal abilities. "Brachiosaurus" appears again in "Jurassic Park III", created by ILM entirely through CGI.


title: Dinosaurs in Jurassic Park

text: "Brachiosaurus" returns in "Jurassic World: Fallen Kingdom", including a scene in which one individual is stranded on Isla Nublar and dies in a volcanic eruption. Director J. A. Bayona stated that this "Brachiosaurus" is meant to be the same one that is first seen in the original "Jurassic Park". For "Fallen Kingdom", the "Brachiosaurus" was created using the same animations from the first film. The "Brachiosaurus" death was the last shot on the film to be finished. Bayona and the post-production team struggled to perfect the CGI, with only several days left to complete the scene. They worked through the final night to perfect the colors and composition, shortly before the film's release. Fans and film critics considered the dinosaur's death scene sad. Reviewers described its death as "poignant" or "haunting", particularly given the species' role in the first film.


title: Dinosaurs in Jurassic Park

text: Their first film appearance is in "The Lost World: Jurassic Park". In the film, the character Dr. Robert Burke, a paleontologist, identifies the dinosaur as "Compsognathus triassicus", which in reality is a non-existent species; the film combined the names of "Compsognathus longipes" and "Procompsognathus triassicus". In the film, "Compsognathus" are depicted as small carnivorous theropods which attack in packs.


title: Dinosaurs in Jurassic Park

text: The "Compsognathus" were nicknamed "Compies" by Winston's crew. Dennis Muren, the film's visual effects supervisor, considered "Compsognathus" the most complex digital dinosaur. Because of their small size, the Compies had their entire body visible onscreen and thus needed a higher sense of gravity and weight. A simple puppet of the "Compsognathus" was used in the film's opening scene, in which the dinosaurs attack a little girl. Later in the film, they kill the character Dieter Stark, who is played by Peter Stormare. For Stark's death scene, Stormare had to wear a jacket with numerous rubber Compies attached.


title: Dinosaurs in Jurassic Park

text: "Compsognathus" make brief appearances in all subsequent films, with the exception of "Jurassic World". In the novels, "Procompsognathus" is depicted with the fictitious feature of a venomous bite, although such a trait is not mentioned regarding their onscreen counterparts. "Compsognathus" returns in the 2022 film "Jurassic World Dominion".


title: Dinosaurs in Jurassic Park

text: A fictionalized version of "Dilophosaurus" appears in the first novel and its film adaptation, both depicting it with the ability to spit venom. The film's "Dilophosaurus" also has a fictionalized neck frill that retracts, and the dinosaur was made significantly smaller to ensure that audiences would not confuse it with the velociraptors. While the real "Dilophosaurus" was thought to have stood at around high, the animatronic was only four feet in height. In addition to the animatronic, a set of legs was also created for a shot in which the dinosaur hops across the screen. The "Dilophosaurus" scene was shot on a sound stage, and the animal's lower body portion was suspended from a catwalk with bungee cords. No CGI was used in creating the "Dilophosaurus".


title: Dinosaurs in Jurassic Park

text: In both the novel and its film adaptation, a "Dilophosaurus" uses its venom on the character Dennis Nedry before killing him. The animatronic model was nicknamed "Spitter" by Winston's team. A paintball mechanism was used to spit the venom, which was a mixture of methyl cellulose, K-Y Jelly, and purple food coloring. The film's idea of a neck frill came from a suggestion by concept artist John Gurche. The animatronic was made to support three interchangeable heads, depending on the position of the frill. The dinosaur's vocal sounds are a combination of a swan, a hawk, a howler monkey, and a rattlesnake.


title: Dinosaurs in Jurassic Park

text: Spielberg initially believed that the "Dilophosaurus" would be the easiest dinosaur to film, although the scene proved harder to shoot that he had expected. The scene is set during a storm, and the use of water to simulate the rain resulted in complications for the animal's puppeteer. A shot not included in the final film would have shown inflatable venom sacs, located under the animal's mouth. These would become visible as the dinosaur spits its venom, which would be expelled from the animatronic's mouth using compressed air. However, the atmosphere was cold and humid on-set, and the compressed air became visible under these conditions. Spielberg resolved the issue by cutting the scene to Nedry as the venom hits him, rather than showing it exiting the animal's mouth.


title: Dinosaurs in Jurassic Park

text: "Dilophosaurus" was popularized by its film appearance in "Jurassic Park", but is considered the most fictionalized dinosaur in the film. Horner, in 2013, described "Dilophosaurus" as a good dinosaur to "make a fictional character out of, because I think two specimens are known, and both of them are really crappy. They're not preserved very well". Paleontologist Scott Persons later said that the "Dilophosaurus" is the most controversial dinosaur depiction in the film series.


title: Dinosaurs in Jurassic Park

text: In "Jurassic World", a "Dilophosaurus" appears as a hologram in the theme park's visitor center. The dinosaur's venom is also referenced in a comedic tour video featured in the film, in which tour guide Jimmy Fallon is paralyzed by the venom.


title: Dinosaurs in Jurassic Park

text: A living "Dilophosaurus" was intended to appear in "Jurassic World: Fallen Kingdom", but the scene was never filmed, as director Bayona decided that it was not necessary. The scene, set on board the "Arcadia" ship, would depict the characters Owen and Claire encountering a "Dilophosaurus" in a cage. Bayona believed that the "Arcadia" scenes were long enough already. "Dilophosaurus" appears in "Jurassic World: Fallen Kingdom" only as a diorama, on display at Benjamin Lockwood's estate.


title: Dinosaurs in Jurassic Park

text: Several "Dilophosaurus" individuals appear in "Jurassic World Dominion", which marks the first living appearance since the original film. One individual has an encounter with Claire, and a trio of the animals later kill Lewis Dodgson, mirroring Nedry's death from the original. Like the first film, no CGI was used to create the "Dilophosaurus", the only animal on the film to lack a digital model. Instead, it was depicted with an animatronic controlled by 12 puppeteers. As with the original film, methyl cellulose was used to create the venom, which was shot out by an off-screen technician.


title: Dinosaurs in Jurassic Park

text: "Dimorphodon", a type of pterosaur, appears in "Jurassic World", marking its first appearance in the series. In the film, the species launch an attack on tourists after being released from an aviary. Through motion capture, dwarf actor Martin Klebba stood in as a "Dimorphodon" during a scene in which one of the creatures tries to attack Owen. A full-scale "Dimorphodon" head was also created. The sound of baby brown pelicans were used as the vocal effects for the Dimorphodon.


title: Dinosaurs in Jurassic Park

text: A group of running "Gallimimus" is featured in the first film, and is encountered by the character of Dr. Alan Grant along with Lex and Tim. The "Gallimimus" were created by ILM entirely through CGI. It was the first dinosaur to be digitized. The "Gallimimus" design was based on ostriches, and the animators also referred to footage of herding gazelles. In the ILM parking lot, animators were filmed running around to provide reference for the dinosaurs' run, with plastic pipes standing in for a fallen tree that the "Gallimimus" jump over. One of the animators fell while trying to make the jump, and this inspired the incorporation of a "Gallimimus" also falling. A portion of the scene depicts a "Tyrannosaurus" killing a "Gallimimus", which was inspired by a scene in "The Valley of Gwangi". Horse squeals were used to provide the "Gallimimus" vocal sounds.


title: Dinosaurs in Jurassic Park

text: "Gallimimus" returns in "Jurassic World", in which a running herd is depicted during a tour. The scene is a reference to the dinosaur's appearance in the first film. This new "Gallimimus" scene was created by Image Engine. The company's artists often viewed the species' appearance in the first film for reference. Jeremy Mesana, the animation supervisor for Imagine Engine, said: "We were always going back and staring at that little snippet from the first film. It was always interesting trying to find the feeling of the "Gallimimus". Trying to capture the same essence of that original shot was really tricky". By the time "Jurassic World" was created, scientists had found that "Gallimimus" had feathers, although this trait is absent from the film.


title: Dinosaurs in Jurassic Park

text: "Giganotosaurus" is introduced in the 2021 "Jurassic World Dominion" prologue. It serves as the dinosaur antagonist in the prologue and the film itself. Trevorrow saved the "Giganotosaurus" for the third "Jurassic World" film to set up a rivalry between it and the "T. rex". In the prologue, a "Giganotosaurus" kills a "T. rex" in battle during the Cretaceous, and two cloned versions face off in the subsequent film, set during the present day. The film presents "Giganotosaurus" as the largest carnivore to have ever existed on Earth, although in reality, the "Spinosaurus" is believed to have been bigger. In the film's climactic scene, the "Giganotosaurus" is killed when the "Tyrannosaurus rex" throws the "Giganotosaurus" onto the claws of a "Therizinosaurus".


title: Dinosaurs in Jurassic Park

text: "Giganotosaurus" was originally meant to be a CGI-only animal, though Trevorrow later decided to have a practical version created as well, to enhance the actors' performances. Animatronic creator John Nolan said the "Giganotosaurus" was "probably the biggest challenge" for his team. The dinosaur was expected to take six months to build, but his team only had about four months to finish it. An animatronic head and neck – the size of a car – were built by Nolan's team, while ILM depicted the rest of the animal through CGI. Nolan initially used a 3D printer to create a one-tenth scale head, on which the animatronic was based. Nolan's team used polystyrene and latex to craft the "Giganotosaurus". The creature was operated on a rig measuring approximately 65 feet in length, and it took six hours to relocate the animal from one set to another.


title: Dinosaurs in Jurassic Park

text: Speaking about the "Giganotosaurus", Trevorrow said, "I wanted something that felt like the Joker. It just wants to watch the world burn". At Trevorrow's request, Nolan added battle scars on the animal's face, similar to Jack Nicholson's Joker character in the 1989 film "Batman". The Joker influence also extended to the dinosaur's lumbering movements.


title: Dinosaurs in Jurassic Park

text: "Indominus rex" is a fictional dinosaur antagonist in "Jurassic World". It is a genetically modified hybrid dinosaur, made up of DNA from various animals. It is created by the character Dr. Henry Wu to boost theme-park attendance, although it later escapes. In the film, it is stated that the dinosaur's base genome is a "T. rex", and that it also has the DNA of a "Velociraptor", a cuttlefish, and a tree frog. The film's promotional website states that the creature also has the DNA of a "Carnotaurus", a "Giganotosaurus", a "Majungasaurus", and a "Rugops". Trevorrow said the mixed DNA allowed the animal to have attributes "that no dinosaur was known to have".


title: Dinosaurs in Jurassic Park

text: The "Indominus" is shown white in color, and can sense thermal radiation. It can also camouflage itself thanks to its cuttlefish DNA, and it uses this ability to evade capture. "Carnotaurus" was previously depicted in Crichton's novel "The Lost World" with the same ability to camouflage. Other characteristics of the "Indominus" include its long arms, raptor claws, and small thumbs. It is able to walk on four legs. ILM's animation supervisor, Glen McIntosh, said: "The goal was to always make sure she felt like a gigantic animal that was a theropod but taking advantage of its extra features". "Therizinosaurus" inspired the long forelimbs of the "Indominus". Horner rejected an early idea that the dinosaur could be depicted as bulletproof, but he otherwise told Trevorrow to add any attributes that he wanted the animal to have. Trevorrow and Horner began with a list of possible characteristics and then gradually narrowed it down. Trevorrow said: "These kind of things were often decided by the needs of the narrative. If it was going to pick up a guy and bite his head off, it was going to need thumbs". Trevorrow wanted the "Indominus" to look like it could be an actual dinosaur, while Horner was disappointed that the dinosaur did not look more extreme, saying that he "wanted something that looked really different".


title: Dinosaurs in Jurassic Park

text: In an earlier draft of the script, the film's dinosaur antagonist was depicted as a real animal despite being a non-existent species in reality. Trevorrow chose to make the antagonist a genetically modified hybrid dinosaur named "Indominus rex", maintaining consistency with earlier films which had generally incorporated the latest paleontological discoveries. He said, "I didn't wanna make up a new dinosaur and tell kids it was real". Fans were initially concerned upon learning that the film would feature a hybrid dinosaur, but Trevorrow said that the concept was "not tremendously different" from dinosaurs in earlier films, in which the animals were partially recreated with frog DNA. He described a hybrid dinosaur as "the next level", and said "we aren't doing anything here that Crichton didn't suggest in his novels". Horner considered the concept of transgenic dinosaurs to be the most realistic aspect of the film, saying it was "more plausible than bringing a dinosaur back from amber". However, a hybridized dinosaur made of various animals' DNA would still be exceedingly difficult to create, due to the complexity of altering the genomes.


title: Dinosaurs in Jurassic Park

text: Trevorrow said the behavior of the "Indominus" was partially inspired by the 2013 film "Blackfish", saying that the dinosaur "is kind of out killing for sport because it grew up in captivity. It's sort of, like, if the black fish orca got loose and never knew its mother and has been fed from a crane". In the film, it is stated that there were initially two "Indominus" individuals, and that one cannibalized its sibling. Fifth scale maquettes of the "Indominus rex" were created for lighting reference. Motion capture was initially considered for portraying the "Indominus", although Trevorrow felt that the method did not work well for the dinosaur. The animal sounds used to create the "Indominus" roars included those from big pigs, whales, beluga whales, dolphins, a fennec fox, lions, monkeys, and walruses.


title: Dinosaurs in Jurassic Park

text: The name "Indominus rex" is derived from the Latin words "indomitus" meaning "fierce" or "untameable" and "rex" meaning "king". The creature is sometimes referred to as the "I. rex" for short, although producer Frank Marshall stated that the film crew abbreviated the name as simply "Indominus". Among the public, the "Indominus rex" was occasionally known during production as "Diabolus rex", a name that Trevorrow made up to maintain secrecy on the film prior to its release.


title: Dinosaurs in Jurassic Park

text: In the film, the character Hoskins proposes making miniature versions of the "Indominus" as military weapons. The "Indominus rex" is later killed during a battle with a "T. rex", a "Velociraptor", and a "Mosasaurus". In the sequel, "Jurassic World: Fallen Kingdom", DNA is retrieved from a fragment of the "Indominus rex" skeleton and is used alongside "Velociraptor" DNA to create the "Indoraptor". The bone sample is later destroyed by the "T. rex" following the death of Eli Mills.


title: Dinosaurs in Jurassic Park

text: "Indoraptor" is a fictional hybrid dinosaur antagonist in "Jurassic World: Fallen Kingdom". It is made by combining the DNA from the "Indominus rex" and a "Velociraptor". In the film, it is created by Dr. Henry Wu on behalf of Eli Mills as a weaponized animal. The creature escapes at Benjamin Lockwood's estate and kills several people, before battling Blue, a "Velociraptor". The "Indoraptor" eventually falls to its death when it is impaled on the horn of a ceratopsian skull, on display in Lockwood's library of dinosaur skeletons.


title: Dinosaurs in Jurassic Park

text: The "Indoraptor" has long human-like arms, which Spielberg considered to be the animal's scariest trait. It is depicted as a facultative biped with a height of approximately tall while standing on two legs. It is portrayed as long and weighing about . The front teeth and long claws were inspired by Count Orlok in "Nosferatu". Bayona chose black for the dinosaur's color to give the appearance of a black shadow, saying "it's very terrifying when you see the Indoraptor in the dark because you can only see the eyes and the teeth". Initially, the film was to feature two Indoraptors, one black and one white. The black "Indoraptor" would kill the white one, in what Bayona considered similar to Cain and Abel. The white "Indoraptor" was ultimately removed from the script as the story was considered detailed enough without it.


title: Dinosaurs in Jurassic Park

text: The "Indoraptor" was primarily created through CGI, although close-up shots used a practical head, neck, shoulders, foot and arm. Neal Scanlan provided the animatronics. An inflatable "Indoraptor" stand-in, operated by two puppeteers on set, was used for some scenes, with CGI replacing it later in production. David Vickery, ILM's visual effects supervisor, said that Bayona wanted the "Indoraptor" to look "malnourished and slightly unhinged". The "Indoraptor" vocal sounds were created by combining noises from various types of animal, including chihuahua, pig, cougar, and lion. The sound of dental drills was also used.


title: Dinosaurs in Jurassic Park

text: Bayona incorporated elements from the 1931 film "Frankenstein" as he wanted to give the "Indoraptor" the feel of a "rejected creature". Bayona said: "There's something of that in the way we introduce the character, the "Indoraptor", this kind of laboratory in the underground facilities at the end of a long corridor, inside a cell. It has this kind of Gothic element that reminds me a little bit of the world of Frankenstein, this kind of Gothic world. And we have also references of people with mental illness, like this kind of shake you see from time to time. It's kind of like a nervous tic that the "Indoraptor" has, and it's taken from real references of mentally ill people".


title: Dinosaurs in Jurassic Park

text: "Mosasaurus" appears in "Jurassic World", as the first aquatic reptile in the films. Earlier drafts for "Jurassic Park III" and "Jurassic Park IV" (later "Jurassic World") had featured the aquatic reptile "Kronosaurus". The "Mosasaurus" was suggested by Trevorrow, as part of a theme-park feeding show in which park-goers watch from bleachers as the animal leaps out of a lagoon and catches its prey: a shark hanging above the water. The park guests are then lowered in the bleacher seats for a view of the mosasaur's aquatic habitat.


title: Dinosaurs in Jurassic Park

text: The "Mosasaurus" was designed to resemble the dinosaurs designed by Winston for the earlier films. Trevorrow said: "We made sure to give her a look and a kind of personality in the way we designed her face that recalled Stan Winston's designs for many of the other dinosaurs in this world. She looks like a "Jurassic Park" dinosaur". Legacy Effects developed the original design for the "Mosasaurus" and ILM refined it. The animators referenced crocodiles for the creature's swimming pattern.


title: Dinosaurs in Jurassic Park

text: The "Mosasaurus" was originally designed as a -long animal, but Spielberg requested that it be enlarged after seeing the initial design. ILM was concerned about making the animal appear too large, but the team was advised by Horner that an increased length would fit within the realm of possibility, as larger aquatic reptiles were consistently being discovered. The animal's length was increased to nearly . Some criticized the "Mosasaurus" for appearing to be twice the size of the largest known species. Horner said "the size of this one is a little out of proportion, but we don't know the ultimate size of any extinct animal". The film inaccurately depicts the "Mosasaurus" with scutes along its back, a trait that was based on outdated depictions of the creature. Audio recordings of a walrus and a beluga whale provided the "Mosasaurus" roars.


title: Dinosaurs in Jurassic Park

text: The "Mosasaurus" returns in "Jurassic World: Fallen Kingdom", in the opening and ending sequences. Compared with the previous film, the "Mosasaurus" is depicted as being larger in "Fallen Kingdom". ILM animation supervisor Glen McIntosh cited this as an example of how "we sometimes have to fudge reality to make something work. From shot to shot, the mosasaurus often changed size slightly to make best use of each frame composition". Although "Mosasaurus" was thought to have had a forked tongue, McIntosh said that the fictional animal was given a regular tongue to make it "more believable to most filmgoers", saying that "we'd played with its scale so much that we felt giving it a forked tongue would be too much".


title: Dinosaurs in Jurassic Park

text: For "Jurassic World" and its sequel, ILM referenced footage of breaching whales, which helped the team determine how to create realistic shots where the "Mosasaurus" leaps from the water. The "Mosasaurus" makes a brief return in the short film "Battle at Big Rock", and in "Jurassic World Dominion" where she is seen sinking a fishing boat and later swimming with a pod of whales.


title: Dinosaurs in Jurassic Park

text: "Pachycephalosaurus" appears in "The Lost World" and its film adaptation. For the film, it was created as a dinosaur measuring eight feet long, though the real animal was long. Three versions of the "Pachycephalosaurus" were created for filming: a full hydraulic puppet, a head, and a head-butter. The latter was built to withstand high impact for a scene in which the dinosaur head-butts one of the hunter vehicles using its domed skull. The puppet version was one of the most complex created for the film, and was used for a scene in which the dinosaur is captured. The legs of the puppet were controlled through pneumatics. Among the public, "Pachycephalosaurus" is the best-known member of the Pachycephalosauria clade, in part because of its appearance in "The Lost World: Jurassic Park". Later research suggested that the animal's skull was not used for head-butting.


title: Dinosaurs in Jurassic Park

text: In "Jurassic World", a "Pachycephalosaurus" briefly appears on a surveillance screen inside the park's control room.


title: Dinosaurs in Jurassic Park

text: "Pteranodon", a pterosaur, makes a brief appearance at the end of "The Lost World: Jurassic Park". Earlier drafts of the script had featured "Pteranodon" in a larger role, and Spielberg insisted to "Jurassic Park III" director Joe Johnston that he include the creature in the third film. "Pteranodon" is prominently featured in "Jurassic Park III", although it is a fictionalization of the actual animal, and it has a different appearance to those seen in "The Lost World: Jurassic Park". In the third film, a group of "Pteranodon"s are kept in an aviary on Isla Sorna. The idea of a pterosaur aviary had originated in Crichton's original "Jurassic Park" novel. An earlier draft of the film had included a storyline about "Pteranodon"s escaping to the Costa Rican mainland and killing people there.


title: Dinosaurs in Jurassic Park

text: The "Pteranodon"s in "Jurassic Park III" were created through a combination of animatronics and puppetry. Winston's team created a "Pteranodon" model with a wingspan of , although the creatures are predominantly featured in the film through CGI. To create the flight movements, ILM animators studied footage of flying bats and birds, and also consulted a "Pteranodon" expert. Winston's team also designed and created five rod puppets to depict baby "Pteranodon"s in a nest, with puppeteers working underneath the nest to control them. The third film ends with a shot of escaped "Pteranodon"s flying away from the island. Johnston wanted an ending shot of "these creatures being beautiful and elegant". He denied, then later suggested, that the fleeing "Pteranodon"s would be included in the plot for a fourth film. Promotional material for the "Jurassic World" films later explained that the escaped "Pteranodon"s were killed off-screen after reaching Canada.


title: Dinosaurs in Jurassic Park

text: Another variation of "Pteranodon" is featured in "Jurassic World", which also depicts them living in an aviary. They are later inadvertently freed by the "Indominus rex" and wreak havoc on the park's tourists. For "Jurassic World", the "Pteranodon" vocal effects were created using audio recordings of a mother osprey, defending her chicks against another individual.


title: Dinosaurs in Jurassic Park

text: "Pteranodon"s make an appearance in a post-credits scene for "Jurassic World: Fallen Kingdom". The scene is set at the Paris Las Vegas resort, where escaped "Pteranodon"s land atop the resort's Eiffel Tower.


title: Dinosaurs in Jurassic Park

text: A "Pteranodon" makes a brief appearance in the short film "Battle at Big Rock", and several individuals appear in the "Jurassic World Dominion" prologue, as well as the main film.


title: Dinosaurs in Jurassic Park

text: The films depict "Pteranodon" with the ability to pick up humans using its feet, although the actual animal would not have been able to do this.


title: Dinosaurs in Jurassic Park

text: "Pyroraptor" appears in "Jurassic World Dominion", becoming one of the first fully feathered dinosaurs in the film series. Designer John Nolan created an animatronic model representing the head and neck, covered in real, red-colored feathers. Various research and efforts were dedicated to properly simulating feather movements. This included the use of wind machines, foam latex, and silicone. The animal is depicted swimming underwater at one point, and research went into various feathers to determine which looked best in such a scene. The feathers were dyed and hand woven onto a net which wrapped over the head, making the feathers move and react with the animatronic.


title: Dinosaurs in Jurassic Park

text: In another scene, the "Pyroraptor" jumps out of the water with its feathers soaked, presenting a challenge for CGI artists. According to David Vickery, ILM's visual effects supervisor, feather and water effects are very difficult to achieve digitally, and the two together presented "a perfect storm of technological complexity". To resolve this, ILM used the 3D software Houdini to adequately depict the feathers. Trevorrow considered "Pyroraptor" the most difficult dinosaur to create, due to the amount of work that went into its feathers.


title: Dinosaurs in Jurassic Park

text: "Spinosaurus" is introduced in "Jurassic Park III" and appears throughout the film, which popularized the animal. After the two previous movies, the filmmakers wanted to replace the "T. rex" with a new dinosaur antagonist. "Baryonyx" was originally considered, before Horner convinced the filmmakers to go with his favorite carnivorous dinosaur: "Spinosaurus", an animal larger than the "T. rex". "Spinosaurus" had a distinctive sail on its back; Johnston said: "A lot of dinosaurs have a very similar silhouette to the "T-Rex" ... and we wanted the audience to instantly recognize this as something else".


title: Dinosaurs in Jurassic Park

text: Winston's team created the "Spinosaurus" over a 10-month period, beginning with a 1/16 maquette version. This was followed by a 1/5 scale version with more detail, and eventually the full-scale version. The "Spinosaurus" animatronic was built from the knees up, while full body shots were created through CGI. The animatronic measured 44 feet long, weighed 13 tons, and was faster and more powerful than the 9-ton "T. rex". Winston and his team had to remove a wall to get the "Spinosaurus" animatronic out of his studio. It was then transported by flatbed truck to the Universal Studios Lot, where a sound stage had to be designed specifically to accommodate the large dinosaur. The "Spinosaurus" was placed on a track that allowed the creature to be moved backward and forward for filming. Four Winston technicians were required to fully operate the animatronic. It had 1,000 horsepower, compared to the "T. rex" which operated at 300 horsepower. Johnston said: "It's like the difference between a family station wagon and a Ferrari". For a scene in which the "Spinosaurus" stomps on a crashed airplane, Winston's team created a full-scale "Spinosaurus" leg prop, controlled by puppeteers. The leg, suspended in the air by two poles, was slammed down into a plane fuselage prop for a series of shots.


title: Dinosaurs in Jurassic Park

text: The film's "Spinosaurus" was based on limited records suggesting what the actual animal had looked like. A scene in the film depicts the "Spinosaurus" swimming, an ability that the real animal was believed to have possessed at the time. Later research proved this theory, suggesting that the animal was primarily an aquatic dinosaur, whereas the film version was depicted largely as a land animal. The roars of the "Spinosaurus" in the film were created by mixing the low guttural sounds of a lion and an alligator, a bear cub crying, and a lengthened cry of a large bird that gave the roars a raspy quality.


title: Dinosaurs in Jurassic Park

text: In "Jurassic Park III", the "Spinosaurus" kills a "T. rex" during battle. Some fans of the "Jurassic Park" series were upset with the decision to kill the "T. rex" and replace it. Horner later said that the dinosaur would not have won against a "T. rex", believing it was likely that "Spinosaurus" only ate fish. An early script featured a death sequence for the "Spinosaurus" near the end of the film, as the character Alan Grant would use a "Velociraptor" resonating chamber to call a pack of raptors which would attack and kill it.


title: Dinosaurs in Jurassic Park

text: A skeleton of "Spinosaurus" is featured in "Jurassic World", on display in the theme park. The skeleton is later destroyed when a "T. rex" is set free and smashes through it, meant as revenge for the earlier scene in "Jurassic Park III".


title: Dinosaurs in Jurassic Park

text: A "Spinosaurus" appears in the fourth season of the animated television series "Jurassic World Camp Cretaceous", which premiered in December 2021. The dinosaur serves as one of several threats to the main characters. Executive producer Scott Kreamer suggested it is the same "Spinosaurus" featured in "Jurassic Park III". Fellow executive producer Colin Trevorrow, when asked if it is the same one, responded "My instinct is actually, no, because it sounds different, but I'm a nerd. So what I don't want to do is mess it up for everyone making "Camp Cretaceous". I'm going to screw this up for them. I found it to be a slightly different animal, like on sight and on sound". The "Spinosaurus" returns in the show's fifth season and eventually engages in battle with a "T. rex", providing fans a long-awaited rematch between the two animals. The "Spinosaurus" retreats when a second "T. rex" approaches.


title: Dinosaurs in Jurassic Park

text: "Stegoceratops" is a hybrid dinosaur made from the DNA of a "Stegosaurus" and a "Triceratops". It makes only a brief appearance near the end of "Jurassic World", when an image of the dinosaur is visible on a computer screen in Dr. Henry Wu's laboratory. An early draft of the film had a scene where Owen and Claire came across the "Stegoceratops" in the jungle on Isla Nublar. The "Stegoceratops" would have joined the "Indominus rex" as a second hybrid dinosaur. However, Trevorrow decided to remove the animal from the final script after his son convinced him that having multiple hybrids would make the "Indominus" less unique.


title: Dinosaurs in Jurassic Park

text: Although the dinosaur is largely removed from the film, a toy version was still released by Hasbro, which produced a toyline based on "Jurassic World". Trevorrow, discussing his decision to remove the "Stegoceratops", said: "The idea that there was more than one made it feel less like the one synthetic among all the other organics, and suddenly it seemed entirely wrong to have it in the movie. I suddenly hated the idea but the toy still exists as a kind of remnant because Hasbro toys are locked a year out". The dinosaur also appears in the video games "" (2015), Jurassic World Alive (2018) and "Jurassic World Evolution" (2018). Outside of the franchise, a "Stegoceratops" had also appeared in the film "Yor, the Hunter from the Future" (1983) where it was coincidentally referred to by that name.


title: Dinosaurs in Jurassic Park

text: "Stegosaurus" appears in the "Jurassic Park" novel but was replaced by "Triceratops" for the film adaptation. The dinosaur's name (misspelled as ""Stegasaurus"") is seen on an embryo cooler label in the film, but the animal is otherwise absent. "Stegosaurus" instead made its film debut in "The Lost World: Jurassic Park", after writer David Koepp took a suggestion from a child's letter to include the dinosaur. According to Spielberg, "Stegosaurus" was included due to "popular demand". In the film, a group of adult "Stegosaurus" attack Dr. Sarah Harding when they spot her taking pictures of their baby, believing that she is trying to harm it. "Stegosaurus" is among other dinosaurs that are captured later in the film.


title: Dinosaurs in Jurassic Park

text: Full-sized versions of an adult and infant "Stegosaurus" were built by Winston's team, although Spielberg later opted for a digital version of the adults, so they could be more mobile. Winston's adult stegosaurs were long and tall. The adults were not used due to mobility issues and safety concerns. Winston's adult "Stegosaurus" is only shown in a brief shot, in which the animal is caged. The baby "Stegosaurus" was long and weighed .


title: Dinosaurs in Jurassic Park

text: "Stegosaurus" has appeared briefly in each film since then. For "Jurassic World", ILM studied the movements of rhinos and elephants, and copied their movements when animating the "Stegosaurus". The film inaccurately depicts "Stegosaurus" dragging its tail near the ground, unlike previous films.


title: Dinosaurs in Jurassic Park

text: "Stygimoloch" is introduced in "Jurassic World: Fallen Kingdom", and was included for comic relief. Its vocal sounds were a combination of dachshund, camel, and pig noises. Sound designer Al Nelson said: "It created this sweet, gurgling kind of thing that fits perfectly with this funny little creature". Horner was surprised by the inclusion of "Stygimoloch", whose existence was considered doubtful by him and other paleontologists; they believed the animal to actually be a juvenile form of "Pachycephalosaurus" rather than a separate dinosaur. Like "Pachycephalosaurus", the "Stygimoloch" had a domed skull, which it uses in the film to smash through a brick wall.


title: Dinosaurs in Jurassic Park

text: For its return in "Dominion", animatronic designer John Nolan studied modern animals which also headbutt. This inspired a scene in which the "Stygimoloch" is captive in an anti-ramming cage; the animal's front half was constructed and visible, while a puppeteer performed its thrashing movements from behind.


title: Dinosaurs in Jurassic Park

text: "Therizinosaurus" is introduced in "Jurassic World Dominion", becoming one of first fully feathered dinosaurs to appear in the film series. Trevorrow was initially excited to include the animal, but had second thoughts upon learning that it was an herbivore. Co-writer Emily Carmichael said that "the rest of us were like, 'It might still have its territory threatened. It might still be formidable and dangerous. Just because it's vegetarian doesn't mean it's a pushover!'" Being an herbivore, Trevorrow considered it challenging to present the "Therizinosaurus" as a scary animal. The filmmakers relied on paleontological discoveries for the animal's design, but also sought to have it resemble Winston's dinosaur animatronics.


title: Dinosaurs in Jurassic Park

text: "Triceratops" makes an appearance in the first film as a sick dinosaur, taking the place of the novel's "Stegosaurus". "Triceratops" was a childhood-favorite of Spielberg's. The "Triceratops" was portrayed through an animatronic created by Winston's team. Winston was caught off-guard when Spielberg decided to shoot the "Triceratops" scene sooner than expected. It took eight puppeteers to operate the animatronic. The "Triceratops" would end up being the first dinosaur filmed during production. Aside from the adult " Triceratops", a baby had also been created for the character of Lex to ride around on, but this scene was cut to improve the film's pacing. To create the "Triceratops" vocals, sound designer Gary Rydstrom breathed into a cardboard tube and combined the sound with that of cows near his workplace at Skywalker Ranch.


title: Dinosaurs in Jurassic Park

text: "Triceratops" makes brief appearances in each of the subsequent films. In "The Lost World: Jurassic Park", a baby "Triceratops" was created by Winston's team for a shot depicting the animal in a cage. For its appearance in "Jurassic World", the ILM animators studied rhinos and elephants, as they did with the "Stegosaurus". In the film, "Triceratops" is depicted galloping, although the real animal was sluggish and would not have been able to do so.


title: Dinosaurs in Jurassic Park

text: "Tyrannosaurus rex" is the primary dinosaur featured in the novels and throughout the film series. For the first film, Winston's team created an animatronic "T. rex" that stood , weighed , and was long. At the time, it was the largest sculpture ever made by Stan Winston Studio. The studio building had to be modified for the construction of the animatronic. Horner called it "the closest I've ever been to a live dinosaur". The animatronic was used in a scene set during a storm, depicting the "T. rex" as she breaks free from her enclosure. Shooting the scene was difficult because the foam rubber skin of the animatronic would absorb water, causing the dinosaur to shake from the extra weight. In between takes, Winston's team had to dry off the dinosaur in order to proceed with filming. Winston's team initially created a miniature sculpture of the "T. rex", serving as a reference for the construction of the full-sized animatronic. ILM also scanned the miniature sculpture for CGI shots of the animal.


title: Dinosaurs in Jurassic Park

text: One scene in the film depicts the "T. rex" chasing a Jeep. Animator Steve Williams said he decided to "throw physics out the window and create a "T. rex" that moved at sixty miles per hour even though its hollow bones would have busted if it ran that fast". In the film, it is stated that the "T. rex" has been recorded running as fast as 32 miles per hour, although scientists believe that its actual top speed would have ranged from 12 to 25 miles per hour. In the novel and its film adaptation, it is stated that the "T. rex" has vision based on movement, but later studies indicate that the dinosaur had binocular vision, like a bird of prey. The "T. rex" roar was created by combining the sounds of a baby elephant, a tiger, and an alligator.


title: Dinosaurs in Jurassic Park

text: In the first film, the "T. rex" was originally supposed to be killed off. Halfway through filming, Spielberg realized that the "T. rex" was the star of the film and decided to have the script changed just before shooting the death scene. The changes resulted in the final ending, in which the "T. rex" inadvertently saves the human characters by killing a pack of velociraptors. Spielberg had the ending changed out of fear that the original ending, without the "T. rex", would disappoint audiences.


title: Dinosaurs in Jurassic Park

text: A "Tyrannosaurus" family is featured in the film sequel "The Lost World: Jurassic Park". The original "T. rex" animatronic from the first film was reused for the sequel, and Winston's team also built a second adult. The adult animatronics were built from head to mid-body, while full body shots were created through CGI. The animatronics weighed nine tons each and cost $1 million apiece.


title: Dinosaurs in Jurassic Park

text: Michael Lantieri, the film's special effects supervisor, said, "The big T. rex robot can pull two Gs of force when it's moving from right to left. If you hit someone with that, you'd kill them. So, in a sense, we did treat the dinosaurs as living, dangerous creatures". The adult animatronics were used for a scene in which the dinosaurs smash their heads against a trailer, causing authentic damage to the vehicle rather than using computer effects. As part of this sequence, an 80-foot track was built into the sound stage floor, allowing the "T. rexes" to be moved backward and forward. The adult "T. rexes" could not be moved from their location on the sound stage, so new sets had to be built around the animatronics as filming progressed. Animatronics were primarily used for a scene in which the "T. rexes" kill the character Eddie, with the exception of two CGI shots: when the animals emerge from the forest and when they tear Eddie's body in half. Otherwise, animatronics were used for shots in which the animals tear the vehicle apart to get to Eddie. Filming the scene with the animatronics required close collaboration with a stunt coordinator. An animatronic "T. rex" was also used in scenes depicting the deaths of Dr. Robert Burke and Peter Ludlow.


title: Dinosaurs in Jurassic Park

text: As in the novel "The Lost World", a baby "T. rex" is also depicted in the film adaptation, through two different practical versions, including a remote-controlled version for the actors to carry. A second, hybrid version was operated by hydraulics and cables; this version was used during a scene in which the dinosaur lays on an operating table while a cast is set on its broken leg. Weeks before filming began, Spielberg decided to change the ending to have an adult "T. rex" rampage through San Diego, saying, "We've gotta do it. It's too fun not to".


title: Dinosaurs in Jurassic Park

text: A "T. rex" appears only briefly in "Jurassic Park III", which instead uses "Spinosaurus" as its primary dinosaur antagonist. In the film, a "T. rex" is killed in a battle against a "Spinosaurus".


title: Dinosaurs in Jurassic Park

text: A "T. rex" appears in "Jurassic World" and is meant to be the same individual that appeared in the first film. Trevorrow said, "We took the original design and obviously, technology has changed. So, it's going to move a little bit differently, but it'll move differently because it's older. And we're giving her some scars and we're tightening her skin. So, she has that feeling of, like, an older Burt Lancaster". Motion capture was used to portray the "T. rex", and a full-scale foot was created for lighting reference and to help with framing shots. Following the film's release, fans began referring to the individual as "Rexy". Phil Tippett had worked on storyboards for the original film and had referred to the "T. rex" as "Roberta".


title: Dinosaurs in Jurassic Park

text: The same "T. rex" returns in "Jurassic World: Fallen Kingdom". For its appearance, ILM sent Neal Scanlan the "T. rex" model previously used for "Jurassic World". Using the model, Scanlan created a full-scale 3D print of the "T. rex" head and shoulders. The life-size "T. rex" animatronic, which had the ability to breathe and move its head, was controlled with joysticks. It was used for a scene where the sedated "T. rex" is inside a cage, while Owen and Claire attempt to retrieve blood from her for a transfusion. The beginning shots of the scene were created using only the animatronic, while the ending shots solely used CGI. The middle portion of the scene used a combination of the two methods. Trevorrow said about the dinosaur, "We've been following this same character since the beginning; she's the same "T. rex" that was in "Jurassic Park" and in "Jurassic World". She is iconic—not just because she's a "T. rex", but because she's "this T. rex"". In the film, the "T. rex" is moved to the U.S. mainland and eventually escapes.


title: Dinosaurs in Jurassic Park

text: The same "T. rex" appears in the 2022 film "Jurassic World Dominion", and its 2021 prologue, which Trevorrow described as an origin story for the "T. rex" "in the way we might get to do in a superhero film. The T-Rex is a superhero for me". The prologue and film present a rivalry between the "T. rex" and a "Giganotosaurus". In the prologue, a "Giganotosaurus" kills a "T. rex" during the Mesozoic. Trevorrow called it "such a horrifying loss for all of us who grew up with the T. rex. To build this into something that feels like a revenge picture that takes place over 65 million years was one of my favorite ideas that we had". In the film, the "T. rex" has been sent to Biosyn's dinosaur sanctuary, where she battles the "Giganotosaurus" for the role of apex predator, ultimately prevailing. Later, she encounters the "T. rex" duo from "The Lost World: Jurassic Park". Trevorrow said he wanted to "really make the audience want her to find peace. We want her to find a home. She feels like she has been constantly displaced, time and time again. For her to find a family and sense of belonging is what I want". For "Dominion", Trevorrow wanted to reuse the animatronic "T. rex" from "Fallen Kingdom". However, it had already deteriorated, as is common for animatronics. Instead, the animal was portrayed entirely through CGI.


title: Dinosaurs in Jurassic Park

text: The physical appearance of the "T. rex" in the early "Jurassic World" films is contrary to new discoveries about the dinosaur. For consistency, the films have also continued to depict the dinosaur with its wrists pointing downward at an unnatural angle, whereas the real animal had its wrists facing sideways toward each other. The "Jurassic World Dominion" prologue features the animal lightly covered in protofeathers. In response to fan criticism about the "T. rex" being portrayed as weak in battles, Trevorrow noted that this individual would be near the end of its life during the "Jurassic World" films.


title: Dinosaurs in Jurassic Park

text: "Velociraptor" is depicted in the franchise as an intelligent pack hunter. It has major roles in the novels and the films, both of which depict it as being bigger than its real-life counterpart. The franchise's "Velociraptors" are actually based on the "Deinonychus", but are larger than the latter. In writing "Jurassic Park", Crichton was partly inspired by Gregory S. Paul's 1988 book "Predatory Dinosaurs of the World", which mislabeled "Deinonychus" as a "Velociraptor" species.


title: Dinosaurs in Jurassic Park

text: John Ostrom, who discovered "Deinonychus", was also consulted by Crichton for the novel, and later by Spielberg for the film adaptation. Ostrom said that Crichton based the novel's "Velociraptor"s on "Deinonychus" in "almost every detail", but ultimately chose the name "Velociraptor" because he thought it sounded more dramatic. Crichton's version of the animal, depicted at tall, was carried over into the film adaptation. The film also states that "Velociraptor"s are long. The "Utahraptor", however, was a more accurate dinosaur in size, length, and height comparison to the franchise's "Velociraptor"s; it was discovered shortly before the 1993 release of "Jurassic Park"s film adaptation. Winston joked: "After we created it, they discovered it". Like their fictional counterparts, real raptors are believed to have been intelligent and may have been pack hunters.


title: Dinosaurs in Jurassic Park

text: In the first film, the raptors were created through a combination of animatronics and CGI. A fully functioning raptor head took four months to create. The creature was also depicted by men in suits for certain scenes, including the death of character Robert Muldoon, who is mauled by one. John Rosengrant, a member of Winston's team, had to bend over to fit inside the raptor suit for a scene set in a restaurant kitchen. Filming lasted up to four hours at a time; Rosengrant said: "My back would go out after about 30 minutes, and that was after having trained a couple of hours a day for weeks". Part of the kitchen scene was initially going to depict the raptors with forked tongues, like snakes. Horner objected to this, saying it would have been scientifically inaccurate, in part because it would imply a link with cold-blooded reptiles. Instead, Spielberg opted to feature a raptor snorting onto a kitchen-door window, fogging it up. This would keep with the idea that dinosaurs were warm-blooded. The various raptor vocals were created by combining the sounds of dolphin screams, walruses bellowing, geese hissing, an African crane's mating call, tortoises mating, and human rasps.


title: Dinosaurs in Jurassic Park

text: "Velociraptor" has appeared in each subsequent film. In "The Lost World: Jurassic Park", a mechanical version of the raptor was created to depict the animal's upper body. A full-motion raptor was also created through CGI. In addition to the regular raptors, a "super-raptor" had also been considered for inclusion in the film, but Spielberg rejected it, saying it was "a little too much out of a horror film. I didn't want to create an alien".


title: Dinosaurs in Jurassic Park

text: In the first film, Muldoon states that the raptors are extremely intelligent. "Jurassic Park III" depicts them as being smarter than previously realized, with the ability to communicate among each other through their resonating chambers. This was inspired by the theory that other dinosaurs, such as "Parasaurolophus", were capable of sophisticated communication. Johnston said "it's not completely outlandish that a raptor using soft tissue in its nasal area could produce some kind of sound and communicate in much the same way that birds do. There's all kinds of evidence of lots of different species of animals communicating. So, I don't think we were breaking any rules there or creating something that was scientifically impossible". The new raptor vocals were created from bird sounds. "Velociraptor" animatronics were used for "Jurassic Park III", and a partial raptor suit was also made for a scene depicting the death of Udesky. Before the release of "Jurassic Park III", most paleontologists theorized that "Velociraptor" had feathers like modern birds. For the third film, the appearance of the male raptors was updated to depict them with a row of small quills on their heads and necks, as suggested by Horner.


title: Dinosaurs in Jurassic Park

text: Paleontologist Robert T. Bakker, who was an early pioneer of the dinosaur-bird connection, said in 2004 that the feather quills in "Jurassic Park III" "looked like a roadrunner's toupee", although he noted that feathers were difficult to animate. He speculated that the raptors in the upcoming "Jurassic Park IV" would have more realistic plumage. "Jurassic Park IV", ultimately released as "Jurassic World", does not feature feathered "Velociraptor"s, maintaining consistency with earlier films. Horner said "we knew Velociraptor should have feathers and be more colorful, but we couldn't really change that look because everything goes back to the first movie". "Velociraptor" is also depicted holding its front limbs in an outdated manner, not supported by scientific findings. Research has also found that the real animal lacked the flexible tails and snarling facial expressions that are depicted in the film.


title: Dinosaurs in Jurassic Park

text: At Spielberg's suggestion, the fourth film includes a plot about four raptors being trained by a dinosaur researcher, Owen Grady (portrayed by Chris Pratt). When Trevorrow joined the project as director, he felt that the plot aspect of trained raptors was too extreme, as it depicted the animals being used for missions. Trevorrow reduced the level of cooperation that the raptors would have with their trainer. Early in the film, the raptors are being trained to not eat a live pig located in their enclosure; Trevorrow said that this "was as far as we should be able to go" with the concept of trained raptors. Owen's relationship with the raptors was inspired by real-life relationships that humans have with dangerous animals such as lions and alligators.