Crossing Ford: A review of Prof. Brian J. Ford’s ‘Too Big to Walk: the New Science of Dinosaurs’.

Introduction:
In his grandiosely titled book, ‘Too Big to Walk: the New Science of Dinosaurs’, Mr. Ford combines a highly interesting history of paleontology with an eccentric hypothesis, long discredited in that science.
The majority of Mr. Ford’s book, is a comprehensive, indeed a near exhaustive history of paleontology and related sciences: beginning with a synopsis of dragon and monster mythology (held by him to be similar in its iconography to present-day paleontological illustration); continuing with a colourful and intricate account of Victorian fossil-collecting; and concluding with a precís of the present state of the science. His account is made all the livelier by such data as the premodern engravings, in Cambodia, of stegosaurids; the rôles of women in early Victorian fossil collection; the full growth and extent of paleontology, even before Owen; the colorful story of Smith’s law of superposition; the wealth and variety of fossils found by past civilizations (such as some Native American peoples); and the emergence of evolutionary theory even before Darwin and Wallace (ch. 1–2).
Only after supplying his readers with this most stimulating information, Mr. Ford turns, fortunately briefly, to his central claim: that large dinosaurs, by reason of their bulk and elongation, were obligatorily semi-aquatic, and actually unable to proceed otherwise over long distance.
For his history of paleontology, Mr. Ford is to be commended, even praised, insofar as the history of science is intrinsically interesting to all scholars, and of even greater necessity among the laity, who would otherwise become possessed of all manner of inaccuracies. For the particular argument for which his book is named, however, he is rather to be criticized; and the aim of the present essay, therefore, is to indicate such weaknesses of that argument, as may arise before a fair and unbiassed examination.
In the present essay, no effort shall be made at mockery of Mr. Ford’s credentials, or of his right to make even the most extra-ordinary claims. Whereas the discovery of new information is the province of experts, commentary upon extant information is the common right of all educated people, if science is not to devolve into orthodoxy and doctrine. Thus, even such eccentricities as Mr. Ford’s, discussed here, are on principle, permissible, and even desirable, however vulnerable to disproof and counter-example. The aim of disproof, in the mind of the present author, is not to suppress views contrary to those prevalent in the science; but to answer such views as they deserve, and advance the debate in the interest of bettering both positions.

Thesis and Statements:
In ch. 7, Mr. Ford elucidates his views as follows: “…Their colossal size, their surprisingly shallow footprints, the occurrence of their skeletons only in sedimentary rocks formed in shallow water … convinced [him] they could only have evolved in an environment of shallow water’.
This view, he claims (ibid.), dawned on him at a visit to a display of fossils, where it occurred to him, that such a weight might be more easily supported by water than air. In this, Mr. Ford asserts his opinion with immense self-assurance, on no other grounds than that the contrary appears impossible to the naked eye. Surely such a premise leaves him and his opinion vulnerable to ridicule. The naked eye, in science, is the instrument only of the amateur or the novice; while informed opinion of every sort, from the philosophies of ancient Athens to the cutting-edges of present-day physics, have always sought to see beyond the physical senses, and seldom referred to the observation itself, except to verify the discoveries beyond it.
To dismiss an observed phenomenon as theoretically impossible, simply out of sheer incredulity, is hardly scientific; and Mr. Ford’s own description (ch. 7) recalls nothing so much as the attitude of a naiïve skeptic: a mental handicap he despises, and teaches his readers to despise, throughout the earlier and better chapters of his book (ch. 1–5). Nearly every mention of the paleontological discoveries of the century before Darwin, is accompanied by reference to some incredulity on the part of prior generations of savants, that so different an order of animals could formerly have inhabited the Earth, at so far removed an era from our own (ch. 3–5); and yet, Mr. Ford expects us to look at the terrestrial giants of our own Cenozoic Era, and declare them the theoretical limit of the attainable mass and volume of any animal on land (ch. 6). Such an incautious juxtaposition of views, is sure to weaken the credibility of his central claim.
Nor is he entirely blameless in other matters: for, when sowing the seeds of doubt in his readers, vis-a-vis the prevalent paleontological hypotheses of our day, Mr. Ford takes the liberty (ch. 6) to mention dubiously, the present opinions of ornithopods as social species, and of large dinosaurs as capable of short bursts of rapid locomotion. This, in spite of organisms of comparable size, possessed of the same capabilities, alive today! The scale of the sizes has changed, but the proportions are similar: an elephant is as large, relative to other animals, as a sauropod formerly, and is yet capable of running at approx. 20 k.p.h. over short distances; and the rhinoceros, hippopotamus, and buffalo, somewhat smaller, are even faster. The majority of these, and of large animals in water and on land, are indeed social animals; and the principle of uniformitarianism, however polysyllabically named, as Mr. Ford complains (ch. 1 & ch. 2), induces us to regard the dinosaurs as likely candidates for a similar lifestyle. Nor is it sound science, to cast doubt upon tangential matters, in the hope thus to strengthen one’s own case by mere contrast.
One suspects Mr. Ford of having been too faithful a lover of the ancients: having rightly and wisely recapitulated the history of paleontology, above and beyond the few facts generally taught, he revives, and even extends, the obsolete conception of large dinosaurs as unable to support their own weight, and buoyed therefore by water. In declaring for this discarded hypothesis, Mr. Ford falls into the same error, whereof he accuses evolutionary science: namely, of raising too great a weight upon too slight a support. He is quite right, in the present author’s opinion, to extend paleontology backward through the ages, and show the prevalence of evolutionary hypotheses even centuries before Messrs. Darwin and Wallace; but to proceed from there, to the supposition of insuperable limits on the variability and viability of evolved features, including magnitude of the organism, is intellectually lazy and ignores the very history he purposes to recount. To claim his own hypothesis correct, without evidence other than the argument, That only so could it exist, is the Achilles’ heel of such as Spinoza, Descartes, and Aquinas; and therefore leaves Ford’s hypothesis without a leg to stand on. Whether his hypothesis be true or false, lies beyond the scope of the present essay: it may be true, or not, and there are scientists and experts enough, to put it to the test. But to present convincing evidence in its favour, is evidently beyond the scope of Mr. Ford’s own book.
The supposition that dinosaurs of any species were rendered slow, or immobile by their size, has been more than once discredited. Even on principle, the idea of impediment by a species’ own features, is characteristic rather of deformities and mutations in individuals, and (as a rule) limited to them. A species may be more or less suited to its environment, and may indeed be extinguished by rapid alterations therein; but it never evolves in a native habitat, in such a fashion as thereby to become unsuited to the same. Any species so handicapped, would upon Darwinian principles become quickly extinct, or survive by a (relatively) swift adaptation, not of habits only, but of the body as well; and this should be evident in the skeletal remains and environmental impressions.
Furthermore, there appears to be no universal theoretical limit on the magnitude of objects: astronomy and paleontology alike have confirmed examples of volcanism, inundation, weather, and evolution, many times larger than any presently known. Mr. Ford’s argument, in that sense, is premissed upon a misplaced uniformitarianism: based not on the continuity of natural phenomena from geologically ancient to recent times, but on the naiive opinion, that if a given phenomenon does not attain a certain magnitude in present times, it could never have done so. Such an opinion is one of the first to be discarded, in any study of paleontology, geology, or any natural science.
To illustrate his hypothesis, Mr. Ford gives us a description of large dinosaurs walking on the beds of rivers and lakes, with the balance of their weight held upright by the water. Whereas this is certainly not unfeasible, as a feat habitually attempted upon encounter with either lake or river, it is difficult to credit as the sole means of rapid movement from one place to another; especially upon consideration, that the trackways of sauropods, hadrosaurs, and others known to travel, either in groups, or along regular routes (either explanation may suffice), are found on the banks and in the shallows of any body of water, and chiefly neither toward nor from, but along the edge. We might, of course, suppose any track left even partly underwater, to have been erased by the water itself; but even there, preservation is far from impossible, and Mr. Ford does furnish us (ch. 7) with an example, wherein the dinosaur appears, indeed, to have waded, and left tracks behind. This has been previously commented upon even by mainstream paleontologists (Bird 1944, cited in McGowan 1991), and may justify the opinion, that large dinosaurs were fully capable of aquatic travel, even if they were equally mobile on land.
Later, Mr. Ford offers (ibid.), that fossil assemblages are often associated with riverbeds, ancient and modern alike, as evidence for his claim, that the larger dinosaurs (from iguanodons to sauropods) preferred to wade. Of course, an assemblage in death does not confirm proximity in life: we need only look at graveyards, slaughter-yards, battlefields, owl-pellets, or the heaps of bones beneath an eagle’s perch after a recent kill, to be apprised of potential discontinuity in this. Proximity to water is a feature of the lifestyle of most terrestrial animals, and most are known to wade, in the process of going elsewhere. Even the tigers and jaguars, though apparently ill-adapted for it, are known to swim; and the low-slung physique of the mustelids, in most species used for swift passage through the undergrowth, is adapted in the otters for an amphibious lifestyle. There is little limit to the uses to which a given assortment of limbs and organs may be put, in the water or out of it, and there are neither grounds nor cause to argue, that any dinosaur was incapable of wading, or even swimming, for any of the usual purposes of animal life. It is only when Mr. Ford characterizes this mode of travel as obligated by the dinosaurs’ immense size, that most paleontologists (ch. 8) balk at his claim.

In the present era, the only truly semi-aquatic large quadrupeds known habitually to walk on the riverbed, are the various species of hippopotamus; and these are no less swift or agile on land, than in the water. Even the beavers, otters, pinnipeds, and the amphibious ancestors of whales are not known to walk along the sea-bed, except perhaps in the transitional periods of their evolution. Their limbs, if wielded at all, serve as paddles. Among reptiles, the crocodiles and marine iguana are known to live mostly in the water; but even they streamline their limbs in the swim, and rely on sidewise oscillations of the tail. The amphibians of the family Salamandridae are known to walk, or crawl, along river-beds; but seldom over long distances. Meanwhile, the elephants and rhinoceri are larger and heavier than the hippopotamus, and no strangers to wading; but as easily mobile on land. Thus the use of analogy is far from conclusive in Mr. Ford’s favor, but may be brought to bear on either side of the question, and sometimes more strongly against him.

Minor Matters:
Having thus far indicated the weaknesses in Mr. Ford’s central hypothesis, we may now turn to some of his peripheral statements: in particular, to his reference to the hadrosaurs as “evolved specifically” for a semi-aquatic lifestyle, and his attempt to describe the reduced forelimbs of the large therapods, as a consequence of the same.

According to his publisher, Mr. Ford is “a fellow of Cardiff University, a former fellow of Open University, [and] a fellow (and former officer) of both the Linnean Society and the Institute of Biology”, and holds still more fellowships in the National Endowment for Science, Technology, and the Arts, and in the Royal Microscopical Society. This makes his principal claim all the more extraordinary, and consigns his peripheral statements to the realm of the outrageous.

A man with so many credits to his name, is at liberty to write whatever he pleases, however unorthodox, for the advantage not of his own specialty only, but of all subjects wherein he has taken an interest; and Mr. Ford’s book, is a perfectly sound example of this liberty. At the same time, a man so credentialed should not sink to taking seriously, that which is meant only in jest. The description of a large therapod’s forelimbs as ‘vestigial’ or ‘useless’, is one such joke, without foundation in zoology, and may be contradicted by the simplest of present-day examples. Seen in its skeleton, the wing of a hummingbird is likewise ‘vestigial’, with its long bones much reduced, and the remaining bones expanded out of all proportion; yet the hummingbird is the most mobile and agile of volant vertebrates, and can fly rings around longer-winged birds. The function of the therapods’ forelimbs, in their reduced state (if such indeed it prove), may be thermoregulatory, or communicative, or even sexual (as, indeed, among saltwater crocodiles), or some other not yet discovered; but it is a mistake, at this point in the proceedings, to regard them as ‘useless’ to the organism, simply by reason of their diminution in the skeletal state.
Even if the description of these forelimbs as ‘vestigial’ is finally borne out by the evidence, it does not follow, that they should overbalance and fall, like their compatriots in Conan Doyle’s ‘Lost World’, without due cause. The ratites and ostriches in modern times, and indeed many other birds, walk easily upon their hind limbs, without any use of the forelimb at all, and locomote with relative facility even on the ground. The high-stepping tread of the herons (Ardea herodias), the waddling of the waterfowl (Anas), the swagger of the corvids, the strutting of the peacock, etc., are all derived features, but no less proof, perhaps, of the feasibility of bipedalism, even without the brachial ‘swing’ distinctive in humans. Nor is there much evidence to suggest quadrupedal motion in the ancestral therapod: the only carnivorous Mesozoic saurians to walk on four legs, were the Triassic Postosuchus and related species, whereas even in the Triassic period, the Coelophysis already stood on its hind legs; and the bodily plan of that species, has persisted into modern times, in the later therapods and present-day Aves.
Secondly, and perhaps more erroneously from a scientific point of view: Mr. Ford reverts (ch. 7) to the conception of hadrosaurs, in particular, as amphibious, on the strength of their informal name of Duck-billed Dinosaurs, and of the eponymous feature: said by him, to have “evolved specifically for eating wet water-weed”. He advances this claim, in spite of chemical and trace evidence, that the hadrosaurs’ typical bill of fare, encompassed ferns, conifers, and even rotten wood (Martin 2005); and despite the observations, that the anseriformes, with similar bills, are not limited to water-weed, but feed as easily on insects, gastropods, and some grasses; whereas, the amphibious hippopotami, though they reside in water, are grazers upon land plants.

“The clue”, Mr. Ford says, “is in the name” of duck-bill: an assertion so frivolous, as to be suspected a jest on his part, and not meant to be believed by his readers at all. However useful to the popular writers as a plot-device, the clue of the name is of little interest in science: one might as well expect a dogfish to bark, a brain-coral to think, or the galactic disc to be fluid on all scales of magnitude, simply because we call it by the name of Milky Way. Were we instead to take his assertion seriously, we must accuse him of taking the initial sensory impression of the fossils as infallible: a school of thought historically despised in most sciences (supra), and based on a decidedly literal-minded empiricism.
The only convincing examples in Mr. Ford’s book, of a plausible preference in dinosaurs for a watery life, are Baryonyx and Spinosaurus; and these are already acknowledged by mainstream paleontology as fish-eaters, and fully capable of wading (McGowan 1991).

Digression:
The layman’s immortal question on the dietary habits of the tyrannosaurs, may only be answered speculatively, until further evidence. The premise of the one argument, is the hypothesis that no organism of such vast bulk, could be an active predator, unless in desperate necessity; and of the other, that such impressive teeth and powerful jaws could not be exclusively the equipment of a scavenger. Both premisses are essentially invalid, and may be shown so by simple syllogism.
On the scale of dinosaur size, as described by numerous paleontologists, the tyrannosaurs are only middle-sized, and no larger, in comparison to their prey, than lions to zebra; and there are many predators, throughout the present era, of a size comparable to that of the prey: wolves are almost half the size of elk; tigers, of buffalo; tiger-sharks are almost equal to dolphins, and crocodiles to antelope. Thus, size and bulk need not be given as limiting factors on the size of any predator. Nor are the dinosaurs an isolated case: it is well-known, and acknowledged even by Mr. Ford himself (ch. 8), that insects, plants, and amphibians were larger in the Mesozoic, and earlier in the Paleozoic, than in the present era: presumably under the same selective pressures, to which we accredit the gigantism of the large dinosaurs.
The kinship of theropods to birds, may supply another item of evidence. On the analogy of the condors, it is permissible to suppose that carrion-birds, and their Mesozoic antecedents may have grown larger than a similarly-built predator; but against this, we may set H. moorei, the ‘veritable Ruc’ of popular literature: almost equal to the condors in magnitude, and yet may easily have been an active hunter. Our understanding of large therapods, if conditioned by such ornithological observations, liberates us from the layman’s question altogether, and exposes avenues for future research.

Conclusion:
Had Mr. Ford re-introduced the semiaquatic hypothesis consistently with the prevalent view of dinosaurs as an evolutionary success (i.e., as a neglected extension of their abilities), he might never have been the subject of ridicule among lifelong paleontologists, let alone journalists; and he himself indirectly acknowledges this, in his derisive references (ch. 8) to the prevalent view. Given, instead, the characterization of his hypothesis as a restriction of dinosaurs’ range of motion, it is not difficult to perceive Mr. Ford’s book, as the embodiment of his own hypothesis: too cumbersome to support itself, and supported, not by water in his own case, but by its author’s loquacity. As a history of paleontology, his book is excellent, and ought to be taught to every student either of that science, or of the history of all sciences; but as an hypothesis pertinent to the locomotion of dinosaurs, it is its own best example, of a clumsy body borne down under its own ungainly weight.

Works Cited:
Ford, Brian J. 2018. Too Big to Walk: the New Science of Dinosaurs. London: Collins.

Martin, Anthony J. 2005. Dinosaurs Without Bones: Dinosaur Lives Revealed by their Trace Fossils. NY: Pegasus.

McGowan, Christopher. 1991. Dinosaurs, Spitfires, and Sea Dragons. Cambridge, MA: Harvard University Press.