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Mathematical Geology, Vol. 32, No. 2, 2000

Godzilla from a Zoological Perspective1 Per Christiansen2 The 1998 TriStar movie Godzilla proved to be a major blockbuster, although not the financial success that was initially anticipated and movie critics have been rather unforgiving. Apart from a radically different external morphology compared to the classic Japanese movie monster, the new Godzilla character apparently was made different from the old version on a number of key points to make him more biologically probable. However, calculations show that his limbs and limb muscles must have been severely undersized to move his huge bulk around at even a leisurely pace, and most other biological problems with the old Godzilla, e.g., growth rates and reptilian physiology at such a massive size, have remained unaltered. The old Godzilla was actually the more plausible from a biomechanical point of view. KEY WORDS: Godzilla, size, body mass, biomechanics, physiology.

INTRODUCTION The 1998 TriStar blockbuster movie Godzilla, allegedly a retelling of the old 1954 Japanese Gojira, but in reality a rather different concept with obvious inputs from many other classic science-fiction movies, saw the emergence of a completely new Godzilla morphology. Many of the classic traits of the most famous of movie monsters were gone, e.g., the maple-leaf spines on the back, the atomic fire breath, and the upright dorsal posture with a dragging tail. The rubberized look has given way to an external covering more resembling a reptilian epidermis and cranial morphology has been extensively altered. Gone were also the massive, columnar limbs, the wide, plate-like feet, and the heavy, lumbering gait. The monster was now able to move at highly impressive speeds, and even attain a gait with a fully suspended flight phase, by default an impossibility for the old Godzilla due to the suitmation technique (a man in a rubbersuit). The new slender, long-limbed, and significantly less monster-like Godzilla bore an uncanny resemblance to the larger theropod dinosaurs, portrayed with great skill and authenticity in the movie Jurassic Park, which of course are 1Received

9 December 1998; accepted 29 June 1999. Museum, Department of Vertebrates, Universitetsparken 15, 2100 Copenhagen Ø., Denmark. e-mail: [email protected]

2Zoological

231 C 2000 International Association for Mathematical Geology 0882-8121/00/0200-0231$18.00/1 °

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factual, not fictional, beings. Apparently producer Dean Devlin, director Roland Emmerich, and creator of the new Godzilla, Patrick Tatopoulos (a name also used for the lead character in the movie), wanted the new Godzilla to be more animal-like, and less a fire-breathing, unstoppable force of nature (see, e.g., Internet reviews by Chua-Eoan, 1998a,b, and Ryan, 1998). The highly advanced computer graphics used in the movie makes this new Godzilla remarkably life-like, despite its astounding size for a terrestrial biped, and its behavior, although hardly realistic from an ethological point of view, is clearly less monstrous than the old Gojira from 1954 or the latest Toho Heisei series from 1989 (Godzilla vs. Biollante) to 1995 (Godzilla vs. Destroyer). The movie critics have often been unrelentlessly hard and unforgiving, but from a zoological point of view, the suggestion that the new Godzilla is more animal-like, and thus more realistic and probable than the old version, is interesting. Is this actually the case, or have the people behind the movie unintentionally substituted one set of impossibilities for another, probably due to lack of knowledge of zoology? It must be emphasized, however, that the following suggestions are all prone to substantial error, as Godzilla is a fictitious character for which no actual data exist. Thus, the conclusions should be considered mere ball park estimates. ESTIMATING THE MASS OF GODZILLA One key parameter in analyses of especially biomechanics or physiology, but also in many other zoological analyses, is body mass. For a fictional character this presents obvious problems. However, masses of extinct animals can reliably be predicted using water displacement methods with scale models, based on the Principle of Archimedes (see, e.g., Alexander, 1985, 1989; Christiansen, 1997, 1999c; Paul, 1997). For a fictional character, however, the meticulous care that is imperative in reconstructing the proportions of the scale model is less relevant. The animal in question does not exist. The commercially available model of the new Godzilla (Fig. 1) is not suited for these experiments as it is water permeable and contains internal electronics (to produce the roar). Thus, all external orifices were covered with clear plasticine and the volume of the model was found. The volume of the model Godzilla was found to be 263.5 ml. As most modern animals, it is assumed that the overall density of Godzilla was about equal to that of water, i.e., 1000 kg m−3 . One important question, however, is the scale of the model compared to the animal in the movie. Although seemingly straightforward when employing a model, in the case of the new Godzilla this presents problems. Because just how big is he anyway? Astoundingly, there is little consensus about this, apparently trivial, question. Ebert (1998) suggested that he was around 300 ft (91.5 m) tall, whereas Orwall (1998) and Goldberg (1998) both suggested that he was around 200 ft (61.0 m) tall. Dean Devlin was quoted as simply stating that he was 20 stories tall (Chua-Eoan,

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Figure 1. Commercially available model of Godzilla used in the analyses. It will be readily apparent to all who have scrutinized the movie that the proportions of the model are very similar to the movie monster, indicating that the model does constitute a reasonable basis for experiments. The model is posed in a similar posture as the movie monster. The model is 20.4 cm tall from top of head to the ground, when standing erect, and is 41.2 cm long along the curves.

1998a,b). A story is usually around 3 m, suggesting that a height of around 61 m is appropriate. It is also not stated whether the values are for the walking posture or the erect posture (see Fig. 1), but I will assume all values are for an upright posture. However, as pointed out by Ebert (1998), in the movie the producers have him apparently change size with the task ahead (hopefully unintentionally), as he clearly is capable of fitting into certain tunnels and other man-made hollows at one point, but later appears much too large for this (compare, e.g., the size of the Park Avenue tunnel with subway tunnels). Thus I have calculated his body mass at various sizes (Table 1). At 61 m he would have an overall length of 123 m, and a body mass of seemingly impressive 7058 metric tons. At his tallest (91.5 m) Godzilla would have had a mass of close to 24,000 metric tons. From a zoological perspective, however, it is evident that this value is very low for an animal of such huge proportions. He appears unrealistically lean. Extant animals above 1–300 kg become progressively stouter as size increases, as noted below, in order to cope with the forces of gravity. This new Godzilla clearly violates this biological rule. Since his design was supposedly inspired by the nonavian theropod dinosaurs, one can evaluate how he compares to them. Using a regression equation, relating overall skeletal length to

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Christiansen Table 1. Size and Proportions of Godzilla at Various Sizesa

Model Godzilla Godzilla Godzilla Godzilla Godzilla

Height

Length

Body mass

20.4 cm 30.5 m 45.8 m 61.0 m 76.3 m 91.5 m

41.2 cm 61.6 m 92.4 m 123.2 m 154.0 m 184.8 m

0.264 kg 880.6 tons 2987.5 tons 7058.3 tons 13813.0 tons 23821.9 tons

a Height

is in the upright position, i.e., not the walking position with the dorsal vertebral column held subhorizontally, and length is overall body length, including head.

body mass in 14 species of theropod dinosaurs, for which masses had calculated by means of the water displacement method (Christiansen, 1999c), I have tried to estimate the mass of a hypothetical theropod of Godzilla’s dimensions. A regression equation was calculated by means of Reduced Major Axis analysis (Fig. 2), Body mass (kg) = 1.3385 ∗ 10−6 (Body length in cm)3.1015±0.5191 with a high correlation coefficient (r = 0.9640). A 123 m long theropod would have weighed 6512.8 tons, less than predicted by the model of Godzilla. However, the largest theropod dinosaur used in the data set was Tyrannosaurus rex TMP 81.12.1, which is 1110 cm long, and has a predicted mass (from displacement experiments) of 6300 kg. However, the above equation predicts a mass of just 3730 kg. Clearly, theropods also became more stoutly built as size increased, as in extant mammals (Christiansen, 1999d). Assuming that Godzilla was a scaled-up Tyrannosaurus, he would have weighed almost a sixth more than the above figure (8572 metric tons). Since the Tyrannosaurus, at a length of just 11 m, was considerably more massively built than predicted by the equation, surely an animal that is 123 m long would have had to be proportionally much more massive than a Tyrannosaurus. The Japanese Godzilla (especially in the Heisei series) is much more ponderous and heavy in build than this new one, but this is actually more in accordance with the patterns of proportional change with size among extant, and also extinct, animals (see, e.g., McMahon, 1975; Christiansen, 1997, 1999a).

GODZILLA’S LIMB PROPORTIONS The limbs of land animals must be strong enough to support the body under the influence of gravity, and during true running, i.e., with an unsupported phase in

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Figure 2. Regression figure relating overall body length to predicted body mass in 14 species of nonavian theropods. The mass had been found by measuring the displaced volume of water. Species range from Ornitholestes hermanni (overall length, 210 cm; predicted mass 16.5 kg) to Tyrannosaurus rex (overall length, 1110 cm; predicted mass 6300 kg).

the stride, the forces the bones must resist become considerably greater (Alexander, 1985, 1989, 1991; Christiansen, 1999c). In geometrically similar animals, bone lengths are proportional to M 0.33 and bone cross sections to M 0.67 , where M is body mass. This implies that the limbs of larger animal are mechanically weaker, or operate closer to the limit of mechanical failure, unless compensatory measures are employed. One such measure could be simply to make the limb bones progressively more stout also. However, over much of their size range animals that walk in an parasagittal fashion with the limbs under the body, do not significantly change shape (Biewener, 1989a, 1989b, 1990). It turns out that they change the position of the individual limb bones to vertical instead. As species size increases, limb postures become progressively more vertical (Biewener, 1989a, 1989b, 1990). This results in the limbs of large animals being subjected to less torsional forces from gravity (Carrano, 1998), and less bending moments from the pull of the muscles, as the ratio of the moment arm of the muscles compared to the moment arm of the ground reaction force increases (Biewener, 1989a, 1989b, 1990). When animals exceed about 300 kg limb postures have become nearly vertical (Biewener, 1989a, 1989b, 1990), and straight limbs, as in elephants or the giant sauropod dinosaurs (Christiansen, 1997), are well suited for support of great mass, acting like Doric columns, but will not allow an animal to trot or run. Thus,

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animals above this size become progressively stouter (Bertram and Biewener, 1990; Biewener, 1989a, 1989b, 1990; Christiansen, 1999a, 1999b). A rhinoceros, which, unlike an elephant, can run with a suspended phase, has very stout long bones. It turns out that most of this increased stoutness is a result of mammals evolving progressively shorter long bones with increased size, not unusually thick ones, as is usually assumed (Christiansen, 1999a). One very curious feature of the new Godzilla is its remarkably long and gracile legs. According to Roland Emmerich (Chua-Eoan, 1998a,b) the lean, long-limbed Godzilla was made that way because, unlike the older version, he was supposed to be very fast moving. Theoretically stride length, and hence speed, can increase as the square root of effective limb length. Probably this is also why he has great knee and ankle flexure (and perhaps this was also done to make him look more like a theropod dinosaur). But is this realistic? Among really large modern mammals only elephants retain long limbs for their mass; other mammals have short, and thus strong limbs (Alexander, 1985, 1989; Alexander and Pond, 1992; Christiansen, 1999a, 1999c). But elephant limbs are largely columnar and lack joint flexure. And of course elephants cannot run, only walk fast (Gambaryan, 1974; Alexander and others, 1979). Their limb bones are not strong enough to have limb flexure or to run. What about an animal that weighs thousands of tons? The lack of limb bones from Godzilla may be circumvented, by measuring the thigh of the model and multiplying by the scale. Another way of finding out how long Godzilla’s femur should have been, were he a theropod dinosaur, is to use the relationship between femoral length and overall body length in theropod dinosaurs (Fig. 3). The thigh of the model is 67 mm long, and if Godzilla were 61 m tall and 123 m long (Table 1), this implies a femur of 2003.5 cm! However, the regression equation for theropod dinosaurs (Fig. 3) predicts that Godzilla’s femur should have been only 1611.6 cm long, 20% less. Total limb length of the model is 142 mm (from hip joint to flat of foot), which implies a limb length of 42.5 m for a 123 m long Godzilla. The regression equation (Fig. 3) predicts a limb length of 39.2 m, which translates into 8% difference, obviously not very much. The modest figure is due to the model having less slightly elongated metatarsals than the movie Godzilla (the metatarsus is raised above ground during locomotion in theropod dinosaurs and also Godzilla). Two things, however, must be borne in mind. First, among extant mammals the large species preserve long bone strength by evolving progressively shorter long bones to size as species size increases, and conversely the individual long bones and total limb length in large mammals is usually much less than predicted from the comprehensive equations (Christiansen, 1999a). Godzilla, however, does just the opposite. Second, the large theropod dinosaurs are considerably more long-limbed than mammals of comparable body mass (Christiansen, 1999c, 1999d). The smaller theropod dinosaurs in many ways resemble extant fast-moving animals, such as large ground birds or gazelles, and it is reasonable to suppose

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Figure 3. Regression figure relating length of the hind limb and length of the femur to overall body length in 21 species of nonavian theropod dinosaurs. Upper regression line is limb length and lower regression line is length of the femur. Regression line for limb length (open squares) is limb length (cm) = 0.2259 (body length in cm)1.0363±0.1690 , r = 0.9405. Regression line for femur (black squares) is femoral length (cm) = 0.0769 (Body length in cm)1.0564±0.1311 , r = 0.9660. Regression lines were fitted to the data by means of Reduced Major Axis analysis. Original data were all collected by the author.

that they ran in a comparable fashion (Christiansen, 1999c). The long legs of the large species, however, meant that their limbs were not strong enough to run on (Christiansen, 1999c). It appears that they were capable of only fast walking, nearly breaking into a run, with long strides (Farlow and others, 1995; Christiansen, 1999c). But the large theropods weighed only up to 6–8 tons. How about an animal that weighs thousands of tons? From a zoological perspective it seems extremely unlikely that Godzilla could possibly have had such long limbs at this massive size. And his great knee and ankle flexure would have exposed his limb bones to huge amounts of bending and torsional moments. This again runs counter with empirical observations on extant and extinct animals.

HOW STRONG ARE GODZILLA’S LIMBS? Among most groups of terrestrial animals, and also the theropod dinosaurs, a clear and highly significant relationship exists between the length of the upper limb bones and their least circumference. Based on measurements taken on 33 species

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of theropod dinosaurs, I have calculated the equation Femoral length (mm) = 6.1727 (Femoral least circumference in mm)0.8665±0.0396 As with the above, the regression line was fitted to the data by means of Reduced Major Axis analysis. The correlation coefficient is extremely high (r = 0.9923). The equation allows us to predict how thick the 2003.5 cm long femur of Godzilla could have been. The result appears mind boggling. The femur would have had a least circumference of no less than 1128 cm! It is possible to calculate how resistant to mechanical failure it would have been. If it were strong enough he could have run; if not, his limbs would simply break if he tried. The principle behind this is beam theory as applied by engineers when constructing, e.g., buildings or bridges. For the sake of simplicity, it is assumed that his femur was circular in cross section and had a solid cross section (i.e., did not contain a marrow cavity). Theropods and many mammals do not have solid long bones. Among terrestrial animals usually only small- to medium-sized species have circular long bones, whereas large animals have long bones with more elliptical crosssectional areas. A circular long bone would be slightly more resistant to breakage for a parasagittal animal such as Godzilla. Thus, in assuming a solid, circular femoral shaft we are probably slightly overestimating the strength of Godzilla’s femur, not underestimating it. Nevertheless, the result is not encouraging. Even with a solid femur with a least circumference of 11 m, the strength indicator value is only 6.51 GPa−1 . If the femur had a marrow cavity, as in most mammals and theropod dinosaurs, this value would have been slightly lower, although not much (a really large marrow cavity of 2 × 2 m would imply a section modulus of 3.728, and a strength indicator value of 5.38 GPa−1 , fully 83% of the value for the solid cross section). Among modern animals, species that run well have strength indicator values of around 25–30 GPa−1 , those that run moderately well have strength indicator values of 15–20 GPa−1 (often large species such as buffalos or rhinos), and slow moving species, such as elephants and hippos, have strength indicator values of 7–10 GPa−1 (Alexander, 1985; Christiansen, 1997, 1999c) The low value of Godzilla’s femur makes it unlikely that he could have run. A few points need to be addressed here. First, the very lean legs of the new Godzilla appear too thin to have allowed a bone with an 11 meter circumference. If such a massive bone was present there would be less room for the muscles. And his hips and thighs appear much too lean in the first place to have accommodated muscles of a size required to move his huge bulk around. The circumference of the thigh of the model at its thickest (around midpoint) is 8 cm, implying a circumference of 24 m in a 61 m tall Godzilla. This is only around twice the circumference of the femur.

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In lateral view the thigh of the model at its thickest is 30 mm, implying that the thigh of Godzilla would be around 9 m wide. Since a circular femur with an 11 m circumference would have a sagittal diameter of 3.6 m, the thigh appears extremely lean compared to scientific restorations of the larger theropod dinosaurs (Paul, 1988). Assuming that 75% of the remaining space was made by the epipodial extensors (e.g., M. iliotibialis, M. iliofemoralis), and that the muscles were circular in cross section (which they appear not to have been, so this actually overestimates their size), the total cross-sectional area for the epipodial extensors would have been 24.2 m2 . The maximal force that can be exerted by muscles is proportional to the cross-sectional area and is relatively uniform in vertebrates (e.g., SchmidtNielsen, 1990). As this value is around 4–5 kg force ∗ cm−2 , Godzilla’s epipodial extensors could maximally have exerted around one million kgf per leg. It sounds impressive, but clearly it is insufficient for an animal with a mass of 7000+ tons and with a 20 m femur that is held subhorizontally during most forms of locomotion, thus providing a very long lever. Clearly something is not right here. If Godzilla, at 7000+ tons, had such skinny legs only two possibilities can make the above ends meet. Either Godzilla had a much thinner femur, in which case he probably could not even stand up, or his muscles are hopelessly undersized, which again would imply that he probably could not even walk. The third possibility is that he is simply made much too skinny for his size. He follows none of the rules of proportional change during size increase of real animals. Furthermore, with such extensive knee flexure his femur would have been subjected to huge amounts of torsional stress. Elephant femora have the same low strength indicator values as Godzilla’s femur, but their limbs are columnar. This would have lowered the actual strength of Godzilla’s femur considerably, perhaps to the point where even slow walking would have been hazardous. The Japanese Godzilla, with his columnar, massive legs and more ponderous walk is actually much more plausible from a biological perspective. Moving slowly is a great way to decrease the amount of force the bones must resist. Rather than a more realistic animal capable of fast running, it would appear that the new Godzilla is a highly anorexic character with long spindly legs that would hardly have allowed him to walk, let alone run, and certainly not with such great knee and ankle flexure. His leg joints are as highly flexed as in small- to medium-sized mammals and dinosaurs, and much more so than in large mammals and dinosaurs. This is very unlikely from a biological perspective. The legs also appear much too thin to be able to accommodate the muscle mass necessary to move thousands of tons about at even the most leisurely of paces. From their skeletal morphology we can say with assurance that the large theropod dinosaurs had relatively much more massively muscled hips and legs than Godzilla, despite their minuscule size compared to him. The new Godzilla seems to violate quite a number of biomechanical rules.

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PRESSURE ON GODZILLA’S FEET An animal as huge as Godzilla exerts potentially a huge amount of force on the ground per square meter. The combined cross-sectional area of the feet of the model is 13.5 cm2 . Since the model is 20.4 cm tall (Table 1), the scale to the real Godzilla, assuming that he is 61 m tall, is 1:299. Providing that the model has approximately the proportions of the real Godzilla, which appears likely, the total area of Godzilla’s feet would thus be 120.4 m2 . At a mass of 7058 metric tons (Table 1) the pressure under his feet would be 586 kilonewtons/m2 . This is a very high value compared to even the largest dinosaurs. A large sauropod such as the diplodocid Apatosaurus would have a mass of 19500 kg (Christiansen, 1997). The combined area of its feet (fore and hind feet, as it was a quadruped) would be around 1.2 m2 (Alexander, 1989). Thus, the pressure on the feet of this giant sauropod would be 162.5 kilonewton/m2 . The very largest sauropods, such as 37 ton Brachiosaurus, or Supersaurus and Argentinosaurus, the latter two which appear to have exceeded 50 tons (Christiansen, 1997), could have exerted pressures of one and a half, or slightly more, times this value. But the pressure under the feet of even the largest sauropods did not approach the huge value of Godzilla. However, when the animals walked the pressure on their feet would have been approximately twice as large, as some feet were now off the ground and thus did not support mass. Thus, for Argentinosaurus the pressure on the feet during locomotion might have approached the value of Godzilla standing motionless. However, when Godzilla walked it too doubled the pressure under its feet, now approaching 1200 kilonewtons/m2 ! And if Godzilla broke into a run (or jumped) this value would shoot through the roof. No animal, extant or extinct, even approaches these extreme values (Alexander, 1989). Even large military vehicles have pressures of only 200–270 kilonewtons/m2 under their tracks (Alexander, 1989). With such an enormous pressure under his feet Godzilla must have been in grave danger of getting bogged down on moist soils (remember he comes out of the ocean). Modern animals with small feet and large body mass, e.g., cattle, are (Alexander, 1989). But maybe an animal as large and allegedly powerful, despite his undersized muscles, as Godzilla did not have to worry about this. Potentially he could have made some rather impressive cracks in the streets though, as indeed he did in the movie.

GODZILLA’S PHYSIOLOGY The new Godzilla is apparently a reptile. In the movie one gets the impression that he used to be a species of iguana prior to being subjected to radioactive radiation. He apparently remains a bradymetabolic ectotherm (“cold-blooded”), which is why the heat-seeking missiles cannot hit him, as he is supposedly colder than the surrounding buildings. However, ectothermic animals too need elevated body temperatures when active, as low temperatures interfere not only with digestion,

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making it an extremely slow process (e.g., Nagy, 1987), but also with the power output of the muscles (e.g., Bakker, 1975; Schmidt-Nielsen, 1990). Godzilla would have been no different. Furthermore, he is extremely large. Since the now classic study by Kleiber (1932) it has repeatedly been verified that basal metabolic rates in mammals scale approximately to (mass)0.75 , although variations, albeit usually not severe, are common (e.g., McNab, 1983, 1986). Since the surface areas of geometrically similar animals scale to M 0.67 , this implies that body volume to surface area increases faster than the decrease in metabolic rate. Calculations on heat transfer with the environment in large dinosaurs show that they could have retained a stabile body temperature considerably above ambient for long periods of time, even if they had been ectothermic (Spotila and others, 1991). Today most paleontologists are, however, convinced that dinosaurs were warm-blooded. When animals move they create a lot of internal heat through muscle metabolism (e.g., Schmidt-Nielsen, 1990). Due to its large volume a large animal can store a lot of heat internally, and its relatively small surface area provides insulation from the environment. It appears highly unlikely that Godzilla, particularly as he was frequently running about, could possibly have been colder than the surrounding buildings. The heatseeking missiles could easily have picked him out (and picked him off, as he is not invulnerable as the real one). Under thermally neutral conditions the basal metabolism of ectothermic vertebrates is around 5–10 times less than in comparably sized endotherms (e.g., Regal and Gans, 1980; Bakker, 1972; Else and Hulbert, 1981, 1987; Ruben, 1995), and during cold conditions the metabolism of ectotherms drops drastically (Nagy, 1987; Schmidt-Nielsen, 1990). Conversely, ectothermic animals usually grow about 10– 30 times slower than endothermic animals (Case, 1978). Alligators reach sexual maturity in the wild at 15–20 years of age, at an average growth rate of 30– 40 cm/year during the fastest growth periods (Chabreck and Joanen, 1979). Even extinct giant crocodiles grew no faster than extant species (Erickson and Brochu, 1999), indicating that even giant ectotherms cannot support elevated growth rates. Under favorable conditions in captivity alligators can grow much faster, but are still only around 1 m long after the first year, and 1.5 m after the second (Coulson and others, 1973). However, under similar favorable and unnatural conditions endotherms also grow faster, making Ruben’s (1995) assertions about the overlap of growth rates in ectotherms and endotherms misleading. According to several Danish ostrich farmers, the birds reach 85–130 kilos within 9–12 months, after which they are shipped to the abattoir. Even assuming the most optimistic growth rate for alligators (Ruben, 1995: Fig. 1) their maximum growth rate amounts to less than one fifth of this. If Godzilla started out as an iguana, how long would it have taken him to reach adult size? The result is staggering. Even if we assume that the iguana was really large (say 100 lbs.), it would have taken him in excess of a thousand years to reach adult size! Even if he was endothermic it would have taken 750 years (equations from

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Case, 1978). Notice that the discrepancy in growth rates between endothermic and ectothermic animals appears relatively modest at such a massive adult size. It must be emphasized, however, that these are very rough estimates. We have no terrestrial animals even remotely approaching this size, probably because 7000+ tons is infinitely larger than the size it is physically possible to attain on land. It is simply not known if the growth rates of ectothermic and endothermic animals really do approach each other. Giant whales, however, such as the blue whale, can grow faster than this, and gain around 90 kg a day on average (Nowak, 1991). But whales live in a gravity-neutral medium, and are fed very nutritious milk in abundant quantities during much of their growth. Thus, little energy is spent on foraging or battling the forces of gravity. Assuming that Godzilla grew twice as fast, every day of his growing life, as the fastest growth rates displayed by whales, it would still have taken him 107 years to attain full size. Even at these very unlikely (from a biological perspective) growth rates he would have had to evade human attention for a very long time. This is hardly likely. But Godzilla was created by exposure to radioactive radiation. Perhaps this also dramatically altered his growth rate? His eggs (for Godzilla is a male) are also enormously much larger than even the largest eggs produced by any land vertebrate. The huge elephant birds (Aepyornis) of Madagascar produced the largest eggs of any known amniote, and at up to 10–12 liters they were around 6 times as large as an ostrich egg. Compared to the characters in the movie, Godzilla’s rather leathery eggs, appear to be around 2.5 m tall. In my office I have a number of ostrich eggs, and a large one, 165 mm tall, has a volume of 1741 ml (including the shell, which weighed 335.06 g). A 2.5 m tall, geometrically similar egg from Godzilla would have had a total volume of 6056 liters! How could gas diffusion possibly take place in such a massive egg? Every biological insight gained into gas diffusion in amniote eggs predicts that it could not. The embryo would suffocate and smother in its own waste products. CONCLUSION Many of the problems raised above also apply for the old Godzilla, and new ones are raised. How can an animal thrive on nuclear radiation? How can its integument be impervious to bullets and missiles? How can it contain an internal nuclear reactor, capable of producing massive amounts of radioactive fire to be expelled at high speeds through the mouth? Why is the mouth and throat not severely damaged by this fire, which seems highly destructive to buildings, ships, military vehicles, and other giant monsters? And how can such huge monsters as Rodan, Mothra, Battra, Megalon, and King Ghidorah possibly fly? This appears completely and utterly impossible. But it is important to bear in mind that these questions are irrelevant. Godzilla and all his daikaiju friends and foes are monsters, not animals. It was never the

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intention that they should mimic living animals, despite a superficial resemblance of some to certain, mainly extinct forms, nor be biologically plausible. Monsters cannot be explained in terms of the laws of physics and one should not attempt to do so. They cannot survive being dissected on a laboratory table, as it then becomes evident that all kinds of odds and ends stick out. The main problem with the new TriStar Godzilla appears to be that the people behind the movie, in the erroneous belief that they had to create a more plausible monster (animal), leaned too heavily on the success of Jurassic Park and The Lost World. They created a character in the theropods’ image, ignoring that they were actually dealing with a fictitious being, and also ignoring its history as an armed nuclear device on legs. Clearly they did circumvent some of the biological problems with the old Godzilla, but most were left unchanged and new ones were added. It is flawed to attempt to pass a fictitious movie monster off as biologically plausible, just because it happens to look better. The claim that the new Godzilla is biologically plausible is false. Godzilla was always a mythical monster, and should remain so. The Toho studios’ new Godzilla series (the Heisei series from 1984–1995) convey the true image of Godzilla to the audience: A nearly invulnerable giant with distinctive mammalian, not reptilian, traits, as also implied by his true name Gojira (an amalgamation of kujira [whale] and gorira [gorilla]), wild and untamable, leaving a trail of monumental destruction in his path. The Japanese movies display Godzilla as the true King of the Monsters, compared to which the Americanized version pales. ACKNOWLEDGMENTS Were it not for the combined efforts and brilliance of director Ishiro Honda, producer Tomoyuki Tanaka, special effects wizard Eiji Tsuburaya, and maestro Akira Ifukube in creating the original Gojira (1954), this paper would never have been written. I am indebted to Professor Peter Dodson, who managed to keep a straight face while making useful comments on the original manuscript of this strange paper, which was not originally intended for scientific publication. Finally, I must extend my gratitude towards the editors of Mathematical Geology, who displayed real character in accepting such an unusual paper. REFERENCES Alexander, R. McN., 1985, Mechanics of posture and gait of some large dinosaurs: Zool. Jour. Linnean Soc., v. 83, p. 1–25. Alexander, R. McN., 1989, Dynamics of Dinosaurs and Other Extinct Giants: Columbia University Press, New York, 167 p. Alexander, R. McN., 1991, How dinosaurs ran: Sci. Am., v. 264, no. 4, p. 62–68. Alexander, R. McN., Maloiy, G. M. O., Hunter, B., Jayes, A. S., and Nturibi, J., 1979, Mechanical stresses in fast locomotion of buffalo (Syncerus caffer) and elephant (Loxodonta africana): Jour. Zool., v. 189, no. 2, p. 135–144.

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