Turtles

**Turtles** are non-fictional air-breathing reptiles native to the planet Earth found on every continent except Antarctica and in salt water, brackish water, and fresh water. They belong to the order Testudines and 14 living families. There are over 300 known species of turtle on Earth, which can be divided into two suborders: the Cryptodirans (tortoises) and the Pleurodirans (turtles). This can be further subdivided into tortoises, fresh water turtles, and marine turtles and while all tortoises are turtles, not all turtles are tortoises.

Testudines' most notorious feature is having a body encased in a bony shell. Although numerous animals, from invertebrates to mammals, have evolved shells, none has an architecture like that of turtles. The turtle shell has a top (carapace) and a bottom (plastron), but its appearance varies between species. The carapace and plastron are bony structures that usually join one another along each side of the body, creating a rigid skeletal box. This box, composed of bone and cartilage, is retained throughout the turtle's life. Because the shell is an integral part of the body, the turtle cannot exit it, nor is the shell shed like the skin of some other reptiles. In contrast to their terrestrial relatives, tortoises, marine turtles do not have the ability to retract their limbs into their shells, the same being true for fellow turtle species with reduced shells. There are no gendered terms for female or male turtles, but juvenile turtles are called hatchlings.

Turtles can live a terrestrial, semi-aquatic, or aquatic life. Due to their heavy shells, turtles are often slow-moving on land. The limbs of Testudines are adapted for various means of locomotion and habits and most have five toes. Tortoises are specialized for terrestrial environments and have column-like legs with elephant-like feet and short toes. The gopher tortoise has flattened forelimbs for digging in the substrate. Fresh water turtles have more flexible legs and longer toes with webbing, giving them thrust in the water. Some of these species, such as snapping turtles and mud turtles, mainly walk along the water bottom, as they would on land. Others, such as fresh water turtles, swim by paddling with all four limbs, switching between the opposing front and hind limbs, which keeps their direction stable. Testudines are solitary animals and while groups of them may live in the same place, conspecific socialization is quite limited.

Turtles are generally opportunistic omnivores and mainly feed on plants and animals with limited movements, but some species, like the green sea turtle, have a diet that changes with age. Terrestrial species are more herbivorous while aquatic species are more carnivorous. Many turtles migrate short distances seasonally, with marine turtles being the only reptiles that migrate long distances. The vast majority of Testudines are diurnal, but a few are nocturnal. Turtles, like other reptiles, have a limited ability to regulate their body temperature. This ability varies between species and with body size. Small pond turtles regulate their temperature by exiting the water and basking in the sun, while small terrestrial turtles move between the sun and the shade to adjust their temperature. Large species, terrestrial and marine alike, have sufficient mass to give them substantial thermal inertia, meaning that they heat up or cool down over many hours.

Humans hunt turtles for meat and use in traditional medicine, however, they also keep terrestrial and fresh water species as pets. Red-eared sliders are among the most popular pet turtles and have become a widespread invasive species. While their sale is heavily regulated in many parts of the United States of America, they are still legally sold in New York City.

## In TMNT

Turtles, notably fresh water turtles, are integral to the *Teenage Mutant Ninja Turtles* franchise as the franchise's titular characters, the Ninja Turtles. They are born as ordinary turtles, but are inevitably altered by a mutation and gain sapience and an anthropomorphic form. The species of the Ninja Turtles is typically not specified throughout their various incarnations, but it is commonly assumed they are of the widely available red-eared slider species. In the second volume of the *Tales of the Teenage Mutant Ninja Turtles* comic, the four Ninja Turtles are revealed to be red-eared slider specimens. This species is also the one used in the 1990 and 2014 live-action films. In the 2012 TV series episode "Never Say Xever", Donatello states he suspects he and his brothers might be either diamondback terrapins or common box turtles. In *Rise of the Teenage Mutant Ninja Turtles*, all four of the Ninja Turtles are explicitly different species of turtles. Raphael is an alligator snapping turtle, Donatello is a spiny softshell turtle, Michelangelo is an ornate box turtle, and Leonardo is a red-eared slider, related to one another solely through their human DNA. This results in their visibly unique character designs in the show, compared to the more homogenized look of previous *TMNT* media.

## World Turtle Day

The purpose of World Turtle Day, May 23rd, sponsored yearly since 2000 by American Tortoise Rescue, is to bring attention to, and increase knowledge of and respect for turtles and tortoises, and encourage human action to help them survive and thrive.

Turtle Day is celebrated worldwide in a variety of ways, from dressing up as turtles or wearing green summer dresses, to saving turtles caught on highways, to research activities. Turtle Day lesson plans and craft projects encourage educating about turtles in classrooms.

## Gallery

Michelangelo before his mutation.Donatello before his mutation.Leonardo before his mutation