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# Book Review: The Science of Middle-Earth

Michel Laurin

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Michel Laurin. Book Review: The Science of Middle-Earth. Amon Hen, 2025, 311, pp.8-22, 38-40.
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Distributed under a Creative Commons Attribution 4.0 International License
BOOK REVIEW: The SCIENCE OF MIDDLE-EARTH

MICHEL LAURIN

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THE
SCIENCE
OF MIDDLE-
EARTH

A New Understanding of
TOLKIEN AND HIS
WORLD

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ILLUSTRATED BY
ARNAUD
RAFAELIAN

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EDITED BY ROLAND LEHOUCC, LOÏC MANGIN,
AND JEAN-SEBASTIEN STEYER

Edited by Roland Lehoucq, Loïc Mangin, and
Jean-Sébastien Steyer

Translated by Tina Kover

Illustrated by Arnaud Rafaelian

ISBN 9781643136165
$29.95 (hardcover) & available in ebook format

<figure><img src="image_7.png" /><figcaption>Cover of the original, French edition
entitled "Tolkien et les sciences"</figcaption></figure>

This book, edited by three scientists passionate about Tolkien's scientific vision, presents the universe of Middle-earth in 40 chapters organized into six sections (Fig. 1). This is the English translation by Tina Kover of a successful book by Roland Lehoucq, Loïc Mangin, and Jean-Sébastien Steyer originally published in French (Fig. 2); the English version bears the same main title (excluding the subtitle) as Henry Gee's 2014 book, with which it should not be confused! Arnaud Rafaelian's beautiful illustrations, in black and white in the English printed version, must have contributed to the book's success. The following analysis applies to both editions of the book, but the pagination mentioned below refers to the English edition, unless otherwise stated.

It may seem surprising that scientists should have edited such a book. Indeed, Roland Lehoucq is an astrophysicist at the CEA (the French Alternative Energies and Atomic Energy Commission), Loïc Mangin is Deputy Editor-in-Chief of the magazine *Pour La Science* (a French edition of the American magazine *Scientific American*), while Jean-Sébastien Steyer is a paleontologist and CNRS researcher at the CR2P (*Centre de recherche en paléontologie – Paris*; one of the three largest research groups in paleontology in the world, with more than 40 tenured research scientists, professors, and curators). This surprise is quickly dispelled when reading the book, as the introductory chapter, by Isabelle Pantin, historian and Professor Emeritus at the prestigious ENS (École Normale Supérieure), underlines Tolkien's early interest in paleontology and zoology (p. XV). This perhaps explains why the 6th section of the book, entitled "A Fantastic Bestiary", is the most developed, with 11 chapters. This book review will focus on the biological and
paleontological aspects that I am most familiar with, and which are particularly well
developed in sections 5 (“Remarkable characters”) and 6.

The first section of the book is entitled “World-Building”. It comprises six
chapters dealing with Tolkien’s life and its impact on his work. It deals with sociology,
mythology, politics, languages, and philosophy.

The second section, comprising four chapters, is entitled “An Anchoring in Space and Time”. It covers the archaeology, history, linguistics and mythology of corruption and dependence. The chapter entitled “Archaeological Remains and Hidden Cities”, by Vivien Stocker, a “Tolkien specialist”, relates the influence of ancient Egypt, and perhaps Mesopotamia, on the architecture of the city of Minas Tirith (capital of Gondor during the 3rd age, in Tolkien’s work). Among other examples, the author cites the only lighthouse in the whole island of Númenor, reminiscent of the Alexandria lighthouse, as well as the mausoleums in which the rulers of Gondor are buried, reminiscent of those of the Ptolemaic rulers, supposedly located near the tomb of Alexander the Great (reigned 336-323 BC). This tomb disappeared, according to Stocker, in an earthquake in 365 B.C., which was before the birth of Alexander! This is a translation error because the French edition indicates the plausible date of 365 A.D. However, the exact date (Erskine 2002: 178) and even why the tomb was lost is uncertain. Other causes have been invoked in the literature, including degradations committed, among others, by Christians, an Armenian conflict in 272 AD (Erskine 2002: 179), and a tsunami that destroyed numerous buildings and monuments, after which the location of the tomb was forgotten. This chapter also contains a very common confusion between archaeology and paleontology, as evidenced by this sentence: “Tolkien’s interest in archaeology is more than a supposition. He is known to have found a fossil jawbone (which he speculated had come from a dragon!) during a trip to the seaside at Lyme Regis” (p. 61). Lyme Regis, on the south coast of England, was one of the first paleontological sites where Jurassic reptiles were found, notably by Mary Anning (1799-1847), who collected ichthyosaurs, plesiosaurs and pterosaurs, many of which were studied by the famous geologist and paleontologist William Buckland (e.g., Buckland 1829).

The third section of the book, entitled “A Complex Environment”, includes four
chapters on landscapes (geomorphological approach), geology, volcanoes and climate.
The chapter on geomorphology, by Stephen Giner, argues that Tolkien clearly drew
inspiration from the myth of Atlantis (which dates back to Plato) for the story of the
sinking of Númenor.

The chapter on geology, by Loïc Mangin, includes a surprising assertion; in a description of an earlier attempt at a geological reconstruction of Middle-earth by Margaret Howes, Mangin states: “she retraces the evolution of the geography of Middle-earth following the fall of Morgoth, at the end of the First Age, and up to the last ice ages of the Pleistocene, which corresponds to a period from 95,000 to 65,000 years ago” (p. 112). We can therefore deduce that Howes placed the end of the First Age before the last ice age of

<figure><img src="image_8.png" /><figcaption>Hawaiian Volcano Observatory, U.S. Geological Survey
http://hvo wr.usgs.gov/kilauea/update/archive/2008/2008_Mar.html</figcaption></figure>
the Pleistocene, which does not fit with the archaeological data; imagine a civilization with advanced metallurgy having existed over 65,000 years ago, if not earlier! But this does not fit very well the paleoclimatological data either, since the last Pleistocene glaciation did not end 65 ka ago, but closer to about 12 ka (WAIS Divide Project Members 2015), and it had begun much earlier, around 115 ka (NEEM community members 2013). However, the suggestion that the dragon's cave in Erebor is a lava tunnel (p. 116) is plausible. Indeed, such tunnels, known from Hawaii (Fig. 3), the Azores, the Canary Islands, California, and Reunion, among other places, can reach large sizes. The author concludes that "While Tolkien did not take his inspiration from real-world geography, the opposite may be true" (p. 117). This double assertion is only partially accurate. Indeed, in the west of Ireland, underwater geological structures have been officially named after Tolkien's work; the author mentions the Lórien Knoll, the Fangorn and Edoras Banks, the Isengard Ridge, and the Rohan, Gondor, and Eriador Seamounts. However, Tolkien apparently drew inspiration from terrestrial geography in at least two cases: the Glittering Caves of Aglarond, based on the caves of Cheddar Gorge (Somerset, England), and the Misty Mountains, inspired by the Swiss Alps (Larsen 2021: 10).

The chapter on volcanoes by Laurent Stieltjes mentions that the Tumladen valley, in which the city of Gondolin is located, appears to be a caldera (a depression formed by collapse of the ground following a major volcanic eruption; Fig. 4). According to the author, Tolkien drew on Viking legends, including the famous Ragnarök legend, for his descriptions of volcanoes (p. 119). The parallels between Sauron and the Roman god Vulcan, both of whom forge in volcanoes (although the most famous objects forged by Sauron

are power rings, rather than weapons), are intriguing (p. 119).

The final chapter of the third section is an attempt by Dan Lunt to reconstruct the climate of Middle-earth, using the same numerical simulation methods to reconstruct the climates of pre-industrial Earth (circa 1800-1850), late Cretaceous Earth, and Middle-earth, for a total of three modeled worlds. We learn that the pre-industrial atmosphere contained around 280 parts per million (ppm) of CO₂, but today's atmosphere contains 397 ppm. This represents an increase of 42%, probably due essentially to anthropogenic effects, including, of course, the burning of fossil fuels (coal, oil, and natural gas), which is a hot topic right now! Worse still, if the current rate of hydrocarbon consumption continues, the concentration of CO₂ could rise to 560 ppm by 2050 (p. 139). Lunt unfortunately uses the expression "Dinosaur Earth" and places the late Cretaceous crisis (K/Pg, for Cretaceous/Paleogene, or K/T, for Cretaceous/Tertiary, in older studies) at -65 Ma; he even adds that this event "killed off the dinosaurs" (p. 128). Actually, dinosaurs are far from extinct (Laurin 2023: 91), since we recognize some 10,900 extant bird species (see https://birdsoftheworld.org/bow/home, accessed January 26, 2023). Also, the famous K/Pg crisis, probably caused by the fall of the Chicexulub meteorite (Yucatan, Mexico; Fig. 5) and the intense volcanism of the Deccan traps (India), took place around 66 Ma (million years ago) (Brusatte 2021), one million years earlier than indicated by Lunt. The simulation

<figure><img src="image_9.png" /></figure>

NASA, Public Domain via https://eol.jsc.nasa.gov/SearchPhotos/photo.pl?mission=ISS005&roll=E&frame=6997
suggests that the Shire's climate was similar to that of Belarus, while Mordor's climate was particularly close to that of Los Angeles and West Texas.

The fourth section of the book, entitled “Spectacular Settings”, comprises six chapters, dealing with botany, subterranean worlds (caves and mines), precious stones, metallurgy, invisibility, and the composition of the One Ring.

Tolkien's humanoids are presented in section 5, entitled “Remarkable characters”, which comprises nine chapters. The first, by Luc Perino, deals with medicine in Middle-earth. He mentions that elves do not experience senescence (p. 205). This surprising phenomenon is biologically plausible for some organisms, but not necessarily in hominids; it has long been believed that certain extant animals, such as turtles, were free from senescence, but some recent work has refuted this hypothesis, at least for some taxa (Warner et al. 2016). However, some models even suggest that “negative senescence” can occur in some circumstances. Negative senescence is defined by a death rate decreasing with age, after sexual maturity and, in general,

fecundity increasing with age (contrary to what is observed in mammals). Some studies (e.g. Vaupel et al. 2004) even claim that this phenomenon could be widespread; cases are known in mollusks (marine gastropods and bivalves), sea urchins, and even vertebrates (hagfish, some teleosts, and squamates)! Among other things, this is due to their increasing size and vigor over time, which protects them from predators. This is particularly true of ectothermic vertebrates (which cannot produce much heat and regulate their body temperature behaviorally, by moving between sunny and

<figure><img src="image_10.png" /><figcaption>Donald E. Davis, Public Domain via http://www.jpl.nasa.gov/releases/98/yucatan.html</figcaption></figure>

shady locations) with indeterminate growth (in which, contrary to what happens in mammals, growth does not cease near sexual maturity, but only slows down gradually over age), such as squamates, crocodilians, and turtles. However, the tendency of biological structures (i.e. organs) to degrade over time may be universal. The taxa most likely to lack senescence or experience negative senescence therefore include organisms that can repair or renew their organs. This includes, for example, trees that renew their leaves and produce new branches and roots throughout their lives (Vaupel et al. 2004:349). Thus, Tolkien's almost eternal elves are only partially biologically plausible.

The second chapter in this section, by Jean-Sébastien Steyer, is entitled “Why do hobbits have big hairy feet?” Steyer explains that, since the same genes are involved in the development of fore- and hindlimbs, hobbits should also have big hands (p. 216). It is true that hands and feet should change in size in similar ways, at least when considered over a short evolutionary period, and without genetic manipulation, but evolution has obviously allowed decoupled changes in the size of these structures. In mammals, there are sometimes major differences between the size of hands and feet, for example in goats, gerbils, and kangaroos, where the metatarsals (bones of the sole of the foot) are much longer than the metacarpals (bones of the palm of the hand).
Even more dramatic size differences between hands and feet can be found in other taxa, including the famous Cretaceous dinosaur *Tyrannosaurus rex*, whose forelimb was so small that we wonder whether it still had any function (Padian 2022). So, differential evolution of the two extremities is possible, at least given enough time.

François Marchal discusses real hobbits in his chapter “When a Hobbit Upsets Paleoanthropologists”, which has a rich paleontological content and is one of the only chapters in the book without an equivalent in Gee’s 2014 book. Indeed, revisions since the 1st edition, dating from 2004, have been minimal, as Gee explained in the preface to the 2nd edition, and the first articles (of a long series) on the real hobbit were only published in 2004. As hominid evolution is of interest to a large number of readers (partly because of anthropocentrism), I could not resist the urge to give it a much more in-depth analysis than the other chapters of the book. I would also like to take this opportunity to provide a number of useful bibliographical references (Marchal has not provided any for this chapter). That chapter deals with a hominid found too recently to have influenced Tolkien. On the contrary, it is Tolkien’s book *The Hobbit* (published in 1937), and its film adaptations, that inspired paleoanthropologists to name a new hominid. This chapter thus documents Tolkien’s influence in the natural sciences.

Why was this hominid nicknamed the “hobbit”? At the time of its discovery (in 2003), Tolkien was very popular, as the *Lord of the Rings* trilogy had been released in cinemas in 2001, 2002, and 2003; Mike Morwood, one of the fossil’s discoverers and co-author of the study, therefore did not hesitate to nickname this little hominid “hobbit” (p. 219). Furthermore, the feet of *Homo floresiensis* are flat (as noted in Steyer’s chapter) and large (Jungers et al. 2009), especially when compared with the length of the femur and tibia (which are very short). These features are reminiscent of Tolkien’s hobbits (p. 221). This real “hobbit” differs substantially from Tolkien’s, however, as the proportions of its feet, with rather long toes, are in some respects more reminiscent of those of chimpanzees (*Pan troglodytes*) than of an *Homo sapiens*. Such feet are less efficient than ours for walking or running, but could be more effective for climbing. In fact, these feet are so primitive that Jungers et al. (2009: 81) suggest that *H. floresiensis* did not derive from *H. erectus* (which is surprising, since no foot is known to have been definitely attributed to *H. erectus*!), but rather from a “more primitive” taxon, suggesting an australopithecine, or an older species of *Homo*, such as *Homo habilis*. This hypothesis, also suggested by characters visible in other parts of the skeleton, is briefly mentioned by Marchal (p. 221-222). Furthermore, this “hobbit” had a small head (Fig. 6), which contained one of the smallest brains of any known hominid, only 380 cm³, according to some estimates, compared with around 1500 cm³ for our species (Brown et al. 2004). This small brain size is very surprising, because until this discovery, it was thought that hominid evolution was characterized by a progressive increase in brain size, particularly evident in *Homo*. However, *Homo habilis*, which was much older (around 2 Ma), had a larger brain (almost 600 cm³), as Marchal points out (p. 221). However, the discovery of the Naledi human (Berger et al. 2015) in South Africa reveals the presence of other hominids with a small skull (whose geological age is unfortunately unknown).

The small hominids (around 1.06 m tall, for the first individual discovered, an adult female), whose discovery is described at the beginning of this chapter, are often referred to as *Homo floresiensis*. They differ greatly from us and could be small *Homo erectus* (Zeitoun et al. 2016), as mentioned by Marchal (p. 219). They would then be the last *H. erectus* representatives, because until the discovery of this “hobbit”, the most recent *H. erectus* known dated from between 117 ka and 108 ka (Rizal et al. 2020). Initially, the first specimen of *H. floresiensis* found (LB1, the holotype of this taxon) was reported to date back to around 18 ka before the present (Brown et
al. 2004). Other older specimens had been dated at 38 ka and 74 ka (Morwood et al. 2004), as well as a more recent specimen, initially dated at 12 ka (Morwood et al. 2005). These relatively recent dates can be explained by the Australian practice of carrying out quick, but not very thorough, excavations. Later, Sutikna et al. (2016) revealed the existence of a stratigraphic unconformity that set back the presence of remains attributable to *H. floresiensis* and its lithic industry to between 190 and 50 ka. Marchal has incorporated these new corrected ages (p. 219). Theoretical coexistence with other human taxa, including *H. sapiens*, remains plausible, but for an earlier period. However, the island of Flores has been inhabited by hominids since at least 840 ka (Moore & Brumm 2007); while only tools attest to this presence, in 2016, human remains about 700 ka old that could be ancestors of *H. floresiensis* were unearthed at the Mata Menge site in the So'a Basin of central Flores island (van den Bergh et al. 2016).

One of the main hypotheses is that the small size of this hominid is linked to island dwarfism (Brown et al. 2004), as it was found on the island of Flores, which covers around 14,000 km² in eastern Indonesia (Fig. 7), and which was probably never connected to the larger islands surrounding it (Lahr & Foley 2004). Did the Flores man already possess rudimentary boats, or did he arrive by chance on a natural raft, as happens regularly for various animals and plants (Egerton 2012)? In any case, the explanation of insular dwarfism mentioned by Marchal (p. 219) is all the more plausible given that the island of Flores was then also inhabited by dwarf elephants (*Stegodon florensis insularis*), whose much larger predecessors are well known (van den Bergh et al. 2008). The history of *Stegodon* on the island of Flores is not detailed by Marchal, who mentions this taxon briefly (pp. 220, 222). It is, however, very relevant and interesting because it helps us to understand the evolutionary pressures that led to a great and fast reduction of the hobbit's body size and how it may have arrived on the island.

Indeed, to reach this island, hominids and elephants had to cross the famous Wallace Line, named after the famous co-discoverer of the theory of evolution by natural selection, which he believed separated two major biogeographical realms, usually referred to as “Indomalayan” and “Australasian” (Cecca & Zaragüeta i Bagils 2015: fig. 5.1). In fact, Wallace had misplaced this line, which should be to the east of Flores; Weber and Lydekker later proposed alternative lines (Mayr 1944), but this island is nevertheless difficult to reach for terrestrial vertebrates (Fig. 7). Once there, these vertebrates find themselves more or less cut off from continental populations or those living on other islands, and their evolution is influenced by the island environment, which can lead to either dwarfism or gigantism, as observed in the Komodo dragons (*Varanus komodoensis*, Fig. 8), which also lived on Flores during the Pleistocene.

According to van den Bergh et al. (2008), *Stegodon* arrived on the island of Flores at least twice. The first immigration gave rise to *Stegodon sondaari*, whose presence

<figure><img src="image_11.png" /><figcaption>Rama, CC BY-SA 3.0 FR <https://creativecommons.org/licenses/by-sa/3.0/fr/deed.en>, via Wikimedia Commons <https://creativecommons.org/wiki/File:Homo_Florensiensis-MGL_95216-P5030051-white.jpg></figcaption></figure>
is attested in Flores 900 ka ago (van den Berghet al. 2008: 16), shortly before its extinction, but the arrival of *S. sondaari* on this island must be much older, as the size of this taxon was already greatly reduced 900 ka ago, with only 300 kg (for an adult). A second immigration of *Stegodon* occurred shortly afterwards, as the much larger *Stegodon florensis florensis* (850 kg) is recorded on the island between 850 and 700 ka (van den Bergh et al. 2008: 31). *S. florensis florensis* may be the direct ancestor of *Stegodon florensis insularis*, whose presence is attested on Flores between 190 and 50 ka, according to corrected dating of Liang Bua cave deposits by Sutikna et al. (2016). According to van den Bergh et al. (2008: 31), these are two subspecies. *S. florensis insularis* was comparable in size to *S. sondaari*, showing a second major size reduction in less than 1 Ma. If such selective pressures were also exerted on Flores hominids, we can better understand the small size of the “hobbit”. According to Marchal, the “hobbit” probably hunted young individuals of these dwarf elephants for food, but other studies do not rule out simple scavenging on the part of *H. floresiensis*. In any case, the accumulation of skeletons of young *S. florensis insularis*

individuals in layers that have yielded numerous stone tools (Moore et al. 2009) and traces left on the bones by such tools strongly suggest that the “hobbit” fed on this small elephant.

*H. floresiensis* seems to have disappeared around 50 ka. It is not known whether *Homo sapiens* interacted with *H. floresiensis* on Flores, as hominids (attributable to *H. sapiens*) are known only in higher stratigraphic levels in the cave sequence, in the Holocene (Morwood et al. 2005, Sutikna et al. 2016). However, *H. sapiens* was already present in Sumatra between 73 and 63 ka (Westaway et al. 2017). Could the latter have exterminated *H. floresiensis*? More data is needed to resolve this question.

<figure><img src="image_12.png" /><figcaption>Kanguole, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
https://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Map_of_Sunda_and_Sahul.svg/1102px-Map_of_Sunda_and_Sahul.svg.png</figcaption></figure>

Indeed, some authors, especially pathologists, have suggested that Flores' 'hobbit' is a pathological *Homo sapiens*. Henneberg et al. (2014) claim that estimates of brain capacity (380 ml) and body size (1.06 m) are biased and too low, estimating these values at 430 ml and 1.20-1.38 m instead. They also dispute Morwood et al.'s (2005: 1016) contention that microcephaly and dwarfism caused by various known pathologies result in normal limb proportions, quite different from those of *H. floresiensis*. On the contrary, according to Henneberg et al. (2014), LB1 traits are characteristic of trisomy 21 (Down's syndrome). They therefore conclude that "the abundant pathological signs that mark cranial and postcranial morphology of the LB1 individual establish a very high probability of that specimen manifesting DS [Down's syndrome]. ... Because teratological individuals are barred as type specimens by the International
<figure><img src="image_13.png" /><figcaption>Midori, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/>, via Wikimedia Commons
https://commons.wikimedia.org/wiki/File:Komodo_dragon_Varanus_komodoensis_Ragunan_Zoo_2b.jpg</figcaption></figure>

Code of Zoological Nomenclature, documentation of serious anomalies in LB1 leaves *Homo floresiensis* as a *nomen nudum*" (p. 11971). Marchal briefly mentions this hypothesis (p. 220). Good arguments have been presented on both sides of the debate. Nevertheless, the discovery of further remains of a small hominid (apparently even smaller than *H. floresiensis*) at Mata Menge dating from 700 ka (see above) weakens the thesis of a pathological *H. sapiens*. This

also suggests that size reduction in this lineage (if the Mata Menge hominid is the ancestor of *H. floresiensis*) occurred very early. Finally, the link between the small size of the Flores "hobbit" (visible both in the appendicular bones of the few known specimens and in the only skull collected) and island dwarfism remains valid, whether this hominid represents an *H. erectus* or a non-pathological *H. sapiens*, but not if it is a pathological individual.

This chapter is enhanced by a figure entitled “A panorama of human evolution”, which shows the stratigraphic distribution and brain size of 26 hominid taxa. The figure includes reconstructions of eight of these hominids. We only regret that Marchal did not link these taxa by kinship, which would have transformed the stratigraphic ranges into an evolutionary tree, but we understand that he may have been reluctant to take this step, given the many controversies surrounding the phylogeny of hominids.

The next chapter in Section 5, by Jean-Sébastien Steyer, is entitled “Gollum: The Metamorphosis of a Hobbit”, and compares the slow transformation of the hobbit Sméagol into Gollum, as well as that of other animals in folk tales (such as werewolves or the frog who turns into Prince Charming), to the metamorphosis of amphibians and insects. According to Steyer, these proven metamorphoses in the animal world could be the source of inspiration for popular myths and for Tolkien. This is possible, but an important difference (mentioned by Steyer) is that the metamorphoses observed in various animals are part of the normal life cycle and take place much faster than that of Sméagol into Gollum, but much slower than that of a human into a werewolf! And the latter is an abnormal and pathological event, though sometimes reversible (werewolves alternate between human and wolf phases). Steyer also wonders whether Gollum could breathe through his skin (p. 231). Although a moist skin such as Gollum's (as depicted in the films) should allow gas exchange, given Gollum's size and the metabolic rate of mammals in general, the skin could only support a tiny proportion of his gas exchange needs. Urodeles, which are among the champions of cutaneous respiration among vertebrates (Reagan & Verrell 1991), have an especially low metabolic rate (Gardner et al. 2020: fig. 1).

Roland Lehoucq and Jean-Sébastien Steyer then discuss “The Eyesight of Elves”, before Sidney Delgado and Virginie Delgado Bréüs ask “Are Dwarves Hyenas?” This latter chapter, which cites numerous scientific sources, draws attention to the masculine characteristics (such as the presence of a beard) of female dwarves in Tolkien’s work, which are vaguely reminiscent of those of female hyenas, insofar as the latter has a highly developed vulva reminiscent of a penis. The authors also discuss the surprising rarity of dwarf females, pointing out that in nature, the ratio of the number of individuals of both sexes is around 1:1, whereas dwarf females are reputed to be much rarer than dwarf males.

The next chapter, by Bruno Corbara, asks “Could an Ent Really Exist?”. The author raises the question of the nature of the Ent, which seems to “be both a plant
and an animal at the same time” (p. 252). In fact, this question may make sense from an ecological point of view (and this is indeed Corbara’s specialty), but from an evolutionary point of view, this does not make much sense. In fact, the old division of the living world into “animal” and “plant” kingdoms is outdated. We long ago realized that a division between eukaryotes (organisms with cell nuclei) and prokaryotes (organisms without cell nuclei) was more fundamental, and even the prokaryote group was subsequently dismantled as it included two quite distinct taxa, the bacteria proper and the archaea. However, plants and animals jointly form only a small part of the eukaryotes, and they are not even closely related to each other. Fungi, for example, are more closely related to animals than to plants. And what we commonly call “plants” is a polyphyletic group (made up of several groups that are not closely related to one another) of photosynthetic organisms. In fact, various groups of eukaryotes (red, brown, and green algae) have acquired chloroplasts (cell organelles where photosynthesis takes place) in parallel, derived from the endosymbiosis of cyanobacteria (the group of photosynthetic bacteria). Contemporary terminology tends to refer only to embryophytes (land plants) by the word “plant”. Corbara mentions that according to Tolkien’s work, Ents seem to have been created, but that as living beings, they must be the product of evolution (p. 253). The author underlines the intermediate nature (from an ecological point of view) of certain groups, such as insectivorous plants (reminiscent of animals in their diet) and corals (reminiscent of plants in their fixed lifestyle, at least during the polyp stage). The case of corals is particularly relevant, as they have photosynthetic endosymbionts, which gives them a certain plant-like character (from an ecological point of view only) and explains their vulnerability to marine pollution; a significant reduction in water clarity reduces the solar energy available to their endosymbionts. The final section of the chapter attempts to determine whether Ents are plants that have acquired characteristics reminiscent of animals, or animals that resemble plants. It concludes that the second alternative is more plausible. The case of Ents that slowly transform into trees, evoked in Tolkien’s work, suggests that Ents can become completely autotrophic or saprotrophic. In this case, a very slow metabolism must be assumed. Corbara mentions “Ents that have reverted to a primitive state (are we to take this as meaning similar to trees?) but which can awaken; indeed, some Huorns take part successfully in the decisive battle against Sauron” (p. 253). From a biological point of view, this is hardly plausible. Such Ents, with their very slow metabolism, would at best move very slowly, like huge sloths; it is difficult to imagine them effectively fighting Sauron’s armies! Unless, of course, we assume that Ents possess an impressive ability to slow down or speed up their metabolism, like some organisms that can suspend their activity. Tardigrades, which can lose up to 97% of their body water and be reanimated after rehydration, and survive 20 months of freezing at -200°C (Miller 2011), are a spectacular (but microscopic) example.

Sidney Delgado and Virginie Delgado Bréüs then discuss genetically modified Orcs. These modifications can involve cross-breeding with humans, or genetic manipulation of DNA such as that which has given us various GMOs (genetically modified organisms). The authors explain (p. 260) that for a cross-breed to be successful, it must involve individuals belonging to the same genus (such as *Homo*, *Equus*, *Panthera* or *Ursus*). In fact, this is a simplification. Defining genera in this way has been proposed (Dubois 1981), but in practice, the capacity for hybridization persists during evolution for highly variable times depending on the taxon – around 2 or 3 Ma in mammals, but more than 20 Ma in birds and anurans (Dubois 1982: Table 2) – and the genus, as a taxonomic level, has no objective reality (Laurin 2010, 2023). It is therefore conceivable that a human could be crossed with an australopitheine or... an Orc! But in most cases, hybrids between relatively distant taxa (including
between species within a group considered as a genus) are sterile, which poses the problem of maintaining such a population.

Jean-Philippe Colin attempts to study the phylogeny of the peoples of Middle-earth. As phylogenetics is my specialty, I could not resist analyzing this chapter in depth, and as Colin did not provide a bibliography, I also take this opportunity to provide references on the paleogenomics and phylogeny of the taxon *Homo*, which are relevant to the analysis of this chapter, as we will see. This original contribution includes cladograms (figures 1 and 2 of the chapter) produced from various characters and the parsimony principle (Hennig 1965), which is mistranslated in the English version (p. 269) by the word "sparse", instead of "parsimony" (the French edition uses the correct word, "parcimonie"). This method is generally considered to apply to entities resulting from evolution. This chapter therefore poses a problem of coherence with Christine Argot and Luc Vivès' contribution on "Language and Evolution in Tolkien" (in the first section of the book), where we read: "There is no common ancestor linking Elves and men; the two races were born of distinct acts of creation" (p. 44). To reconcile the two chapters, we could consider that these distinct creations refer to the mythology of Middle-earth, but that as for our Earth, its biosphere is the result of biological evolution.

A more serious problem is raised by Larsen's (2021: 15) assertion that humans and elves are one species, an assertion based on a rather extensively commented letter from Tolkien to Peter Hastings dating from 1954 (Carpenter 2000). In this letter, Tolkien states, "Elves and Men are evidently in biological terms one race, or they could not breed and produce fertile offspring – even as a rare event". As Larsen (2017: 10) mentioned, Tolkien is confusing race and species here, since race is a rank lower than subspecies, and individuals belonging to distinct races (or even distinct subspecies) of the same species normally give fertile offspring (Lherminier & Solignac 2005). But let's consider, as Larsen (2017) did, that Tolkien only confused two terms here, and that his biological reasoning is otherwise correct. Tolkien's work mentions four cases of union between Elf and human, and all resulted in fertile offspring, including fertile males. We can therefore conclude that, according to a certain vision of the biological concept of species, elves and humans form a single species.

Larsen (2017: 12) goes much further in her analysis and even concludes that humans are closer to elves than to Neanderthals, who are often considered a distinct species (*Homo neanderthalensis*), but sometimes (e.g. by Andreeva et al. 2022) only a distinct subspecies (*Homo sapiens neanderthalensis*) within our species (*Homo sapiens sapiens*). Uncertainties about the extent of gene flow between Neanderthals and our ancestors, and the vagueness surrounding the definition of species (Ereshefsky 2002, Laurin 2023), no doubt explain why this nomenclatural question has not been settled.

But let's return to Larsen's (2017) surprising assertion about the proximity between humans, elves and Neanderthals. We saw that humans and elves produce fertile male offspring, but it seems that hybrids between humans and Neanderthals did not produce fertile males. Indeed, paleogenetic analyses have concluded that the Neanderthal Y chromosome is extinct, despite an ancient and limited gene flow between Neanderthals and our ancestors (Mendez et al. 2016). This is in line with the famous geneticist Haldane's (1922: 101) rule that "When, in the $F_1$ offspring [the first generation of descendants] of two different animal races [taxa] one sex is absent, rare or sterile, that sex is the heterozygous sex". In humans, males have an XY karyotype, while females are XX. Hybrids between Neanderthal and us (*H. sapien*, or *H. sapien sapiens*, depending on the nomenclature) would therefore have included only females, or hybrid males, if they existed at all, would have been sterile. This seems consistent with other paleogenetic findings concerning gene flow between
Neanderthals, Denisovans (hominids closer to Neanderthals than to us), and humans (Prüfer et al. 2014, Sankararaman et al. 2014 and 2016, Meyer et al. 2016, Slon et al., 2018, Rogers et al. 2020).

An important problem with Colin's main cladogram (figure 2 in the chapter) is that it places humans and elves on opposite sides of the basal dichotomy, which implies that all of Tolkien's humanoids (all of which appear on that tree) form a single species, given that Tolkien considered Elves and humans to belong to the same species, and that both races produce fertile offspring. This is possible under certain species concepts, especially as gene flow between these various hominin races seems to be minimal, but cladograms generally apply to distinct taxa (typically, at the very least, several species). Indeed, Colin seems to consider that he is analyzing distinct species, because to introduce his analysis, he wrote (p. 264) that he wanted to "clarify, scientifically, the ties of kinship between the **species** of Middle-earth!" (my emphasis). This position, at least as far as elves and humans are concerned, is clearly contrary to Tolkien's thinking.

However, the analysis is not without interest, at least if we take it as an intellectual exercise. For example, Colin groups the Elf and Ent "taxa" in the Perenosylvans, "for their long lives and the fact that they dwell in wooded ("sylvan") areas" (p. 270). This result is surprising, since Ents are perhaps the most different of all these peoples, because of their vegetal appearance, but the extreme longevity of the individuals of these two taxa seem to be a valid shared derived characteristic, since this great longevity, unknown in mammals, can only be derived (an evolutionary novelty). Cladistics does indeed group by derived characteristics, while ignoring overall similarity. But it seems very unlikely that Ents could hybridize with Elves!

The final section of the book, "A Fantastical Bestiary", comprises 11 chapters, of which only a selection will be reviewed here. The first, by Luc Vivès and Christine Argot, "Mythotyping Origins", suggests (among other things) that "As for the nameless winged creatures ridden by the Nazgûl, they seem to be related to fossil reptilian species such as pterosaurs, but in some sort of teratological, or malformed, combination" (p. 280). This is possible, but it should be pointed out that pterosaurs were very light, with hollow bones filled by air sacs, like birds, and that only the largest known pterosaurs, with a wingspan of 10-11 m and a mass estimated, according to the authors, between 70 and 250 kg (Witton & Habib 2010, Padian et al. 2021: 245), might have been able to lift an adult human, if their mass was closer to 250 kg than to 70 kg.

The chapter on "Wargs: War-Dogs of Scandinavian origin?" by Vincent Dupret and Romaric Hainez mentions Scandinavian legends according to which mythical characters rode wolves. These legends may well have influenced Tolkien, for in any case, the name "warg" is derived from the word "wolf" in various Germanic languages (Larsen 2021: 16). However, the argument that wargs could be inspired by *Canis dirus*, a wolf that became extinct 9500 years ago, is fragile. Indeed, this wolf was about the size of today's largest wolves (Anyonge & Roman 2006), so much smaller than the beasts shown in the films inspired by Tolkien's work. The films are not always a faithful translation of Tolkien's work; Larsen (2021:16) mentions that Peter Jackson "often takes artistic liberties with visual aspects of Middle-earth". But it is hard to imagine wolves riding in armor on animals the size of large wolves.

Stéphane Jouve has contributed two thematically linked chapters. The first, entitled "Smaug, Glaurung, and the Rest: Monsters for Biologists Too", mentions "It would have been more realistic biologically if Smaug's wings were modified forelegs, but drawings by Tolkien himself of Smaug clearly show him with four legs plus two wings" (p. 335). Indeed, in flying vertebrates (pterosaurs, birds, and bats), the wing is always a modification of the forelimb (as Jouve discusses on p. 343, in the next
chapter), and among vertebrates, only teratological individuals (“monsters”) have more than two pairs of limbs. Some gliding vertebrates do have wings plus two pairs of limbs, but their wings are fixed (incapable of flapping flight) and their skeletal support consist either of elongated ribs that can be unfurled, as in the extant squamate *Draco* (Russell & Dijkstra 2001) or the triassic kuehneaurids (Stein et al. 2008), or of bone rods (probably dermal), as in the Permian weigeltisaurids (Buffa et al. 2022). Given the persistence of dragons with four legs plus a pair of mobile wings (i.e., three pairs of limbs) in popular culture (which is irritating, for biologists), this was indeed a point that deserved attention. But this may now be changing. Peter Jackson’s adaptation of *The Hobbit* shows Smaug with only two pairs of limbs, and the forelimb is made up of wings also used for walking, as in bats and, judging by the fossilized footprints at the Crayssac site (France), pterosaurs (Mazin et al. 1997, 2003).

Jouve’s second chapter tackles two dragon-related questions, as indicated by the title: “Flames and Wings... Could it Really Happen?” He argues that dragons’ fire is fueled by methane and hydrogen, as they are “produced by bacteria in the intestines and are also present in the stomach” (p. 341). In a previous analysis (Laurin 2019), I had briefly mentioned hydrogen as a potential fuel to lighten dragons and enable them to fly. This was to provide an alternative to helium, which had been proposed by a colleague to allow dragons to create fire and to fly; helium is certainly light, but incombustible. However, molecular hydrogen ($H_2$), as well as its ionized form ($H^+$), are highly reactive, and during digestion, most of these substances are converted into methane ($CH_4$), which is produced in much greater quantities by digestion, particularly in farmed cattle. This phenomenon has been studied because methane is a powerful greenhouse gas (Moss et al. 2000). Jouve rightly raises the question of the mechanism by which dragons start fires, which is not really solved.

Another tricky point tackled by Jouve’s second chapter is the mechanism by which dragons fly. This is even more problematic than he demonstrates, because Jouve’s analysis is based on a comparison with the Komodo dragon (Fig. 8), which contains an error. Indeed, Jouve claims that if the dragons imagined by Tolkien have proportions similar to those of *Varanus komodoensis* (which is plausible), given that a 3 m-long Komodo dragon weighs 70 kg, a 20 m dragon (the size he estimates for Smaug) would weigh 470 kg. This value seems to come from a rule of three, which gives approximately 467 kg. But this assumes a linear proportionality between mass and length, whereas if the shape remains constant, the mass should grow as the cube of linear dimensions. This more exact calculation gives an estimated mass of 20,741 kg (almost 21 tons), not to mention the problem of estimating the dragon’s body density. Indeed, Tolkien specifies that Smaug is covered in iron scales and hard gemstones, which are far denser than the keratin scales (the substance that also makes up our hair and fingernails) of Komodo dragons. Nevertheless, in Peter Jackson’s film (which does not necessarily reflect Tolkien’s writings on this point), Smaug has a very elongated body, more reminiscent of a snake than a Komodo dragon (except that he has limbs). In this case, and assuming a trunk about twice as wide as that of a Komodo dragon and the same body density, Smaugs’ mass would be substantially less, around 1868 kg. This is still much more massive than any known flying animal (present or extinct) which barely reached a mass of between 70 and 250 kg (see above). We can therefore only agree with Jouve when he concludes that the ability of huge mythological or imaginary dragons to fly is incompatible “with the biological reality” (p. 346).

The final chapter of the book, by Benoît Grison, focuses on cryptozoology. This science of “hidden animals”, as its etymology suggests, aims to discover taxa unknown to science, but whose existence is suggested by more or less reliable and numerous testimonies, or even by mythology. It can therefore be likened to a form of ethnozoology. As Grison points out, this science, founded in the 1950s by the Franco-
Belgian zoologist Bernard Heuvelmans, can either disprove the existence of certain animals, such as the Loch Ness monster, or discover new taxa. This approach led to the discovery of the Saola (Pseudoryx nghetinhensis), a small (80–100 kg), very rare bovine that lives in northern Vietnam (Van Dung et al. 1993). Not surprisingly, it had been over 50 years since any new species of large mammal had been discovered. And the Saola is so different from other known taxa that Van Dung et al. (1993) decided to erect a new genus for this animal. Another example mentioned by Grison is the Coelacanth (Latimeria), the only extant actinistian, which was discovered long after fossils of the ancient actinistians (Devonian to Cretaceous). In fact, before the discovery of the Coelacanth, actinistians were thought to have been extinct since the Cretaceous (at least 67 Ma ago). Thus, nature could still hold such surprises in store for us, particularly in under-explored environments such as the deep sea, or among small animals. Grison goes on to mention that the search for large sea snakes continued during Tolkien's youth, which could explain his interest in dragons (here is the link between cryptozoology and Tolkien's work). This is quite possible, but given the size of the mythological dragons (if the legends are to be believed), it is highly unlikely that we will ever find a dragon in the wild! However, the search for the legendary sea serpents was not in vain. As Grison sums up: "Of the some 400 seemingly credible sightings reported over the last two centuries, many are clearly suggestive of rare marine animals such as the giant oarfish (or ribbonfish, the world's longest bony fish), the whale shark, or even the leatherback sea turtle" (p. 366).

The book therefore covers a wide range of topics related to Tolkien's work and touches on a large number of scientific fields. Larsen (2021: 4) criticized the lack of references to secondary sources (publications that have analyzed Tolkien's work) in the book. In fact, the use of such sources (which are not cited in the text, but are listed at the end of the book) varies greatly among authors and chapters. It is true that three chapters (on sociology, economics and politics, respectively) by Thierry Rogel mostly quote sources on other subjects. But some authors, such as Damien Bador (who contributed two chapters, on history/historiography and linguistics) cite only works by Tolkien and a few secondary sources on this subject, and most chapters cite at least a few secondary sources on Tolkien, or works by this author. One of the introductory chapters, by Isabelle Pantin, references numerous secondary sources on Tolkien, including the excellent book by Henry Gee (2014). This criticism cannot therefore be generalized to the book as a whole, far from it.

Larsen (2021: 2) also claimed that this book uses Tolkien's work to talk about science, but that it does not really deal with science in Tolkien, since most of the contributors are unfamiliar with the author's work. As I am not a Tolkien specialist, I cannot judge the validity of this criticism, which would in any case apply equally to my analysis. However, the preface to the book is clear on the goal of the book: "to use Tolkien's universe – its history, languages, geography, monsters, and characters – to speak about the human, physical, and natural sciences" (p. vii). The aim is not to describe how science would have been practiced in Middle-earth, nor even necessarily to expose Tolkien's ideas on the sciences that underlie his work; these are two interesting themes, but not the ones addressed in this book. If this book takes advantage of Tolkien's popularity to disseminate scientific knowledge to a wide audience and arouse interest in science and perhaps even scientific vocations, it will have played a positive educational (and entertaining) role.

This analysis benefited from comments and bibliographical information (especially on paleoanthropology) from Valéry Zeitoun (CR2P, Paris), whom I thank warmly.

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## FIGURE LEGENDS

Figure 1. Cover of "The Science of Middle-earth".

Figure 2. Cover of the original, French edition entitled "Tolkien et les sciences".

Figure 3. Entrance to a lava tube in Hawaii National Park (the orange color comes from the sky, the photo being taken from inside the tube). Public domain photo, downloaded from https://commons.wikimedia.org/wiki/File:Close-up_of_a_skylight_on_coastal plain_with_lava_stalactites forming_on_the_roof_of_the_tube.jpg

Figure 4. Caldera of La Cumbre volcano (Galapagos), photographed from the International Space Station. This caldera is relatively small but deep; some have a much larger diameter, such as the Yellowstone (Wyoming) or Ngorongoro (Tanzania) calderas. Public domain photo, downloaded from https://commons.wikimedia.org/wiki/File:La_Cumbre_-_ISS.JPG

Figure 5. Artistic reconstruction of the Chixulub meteorite fall 66 Ma ago. Painting by Donald E. Davis. Public domain image downloaded from https://commons.wikimedia.org/wiki/File:Chixulub_impression - artist_impression.jpg

Figure 6. Skull of Flores man, the "hobbit". Photo by Rama of a cast of LB1 on display at the *Musée cantonal des sciences naturelles* (Lausanne). Image published under the "Attribution-ShareAlike 3.0 France" license, downloaded from https://commons.wikimedia.org/wiki/File:Homo_Floresiensis-MGL_95216-P5030051-white.jpg

Figure 7. Map showing Wallace's line, which roughly separates (but not as well as Lydekker's line) the Indomalayan and Australasian biogeographical zones. The island of Flores is highlighted in red. The last glacial maximum was about 23 ka BP. Image published under the "Attribution-ShareAlike 4.0" license, modified (highlighting of the island of Flores ) from https://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Map_of_Sunda_and_Sahul.svg/1102px-Map_of_Sunda_and_Sahul.png

Figure 8. Komodo dragon (*Varanus komodoensis*). Ragunan Zoological Garden (Jakarta, Indonesia). Image published under "Attribution-ShareAlike 2.1" license, downloaded from https://commons.wikimedia.org/wiki/File:Komodo_dragon_Varanus_komodoensis_Ragunan_Zoo_2b.jpg