Spinosaurus, aquatic animals, and jargon

Two weeks ago, another volley was fired in the ongoing Spinosaurus wars. Long known only from remains that were destroyed during World War II, this North African dinosaur has been the subject of numerous scientific publications over the last decade thanks to a newly discovered partial skeleton, which was first described in 2014. With its long, narrow snout, daschund-like hind limbs, and a six-foot ornamental sail on its back, Spinosaurus was an extreme and unusual dinosaur, and it’s easy to see why it’s of such interest to paleontologists, laypeople, and children alike. 

Reconstructed Spinosaurus skeleton at the Hong Kong Science Center. Photo by Hong Kong Tourism Board

Nevertheless, the profound weirdness of Spinosaurus has also made it contentious. What was this animal doing that necessitated the evolution of such bizarre features? Paleontologists agree that it was a specialized fish-eater, as evidenced by its long snout, straight, conical teeth, and nostrils high up on its head (enabling it to breath while keeping its mouth submerged). But while some authors (e.g. Hone and Holtz 2020) imagine Spinosaurus as a heron-like animal, snatching fish from the shallows while wading or standing on the shore, others (e.g. Ibrahim et al. 2020) see evidence for a creature that was at home in the water, swimming after its prey. Naturally, there is also a full gradient of options between the extremes.

The newest publication, by Paul Sereno and colleagues, ground-truths some details of Spinosaurus anatomy. The authors compared parts like the feet and the tail vertebrae to modern animals, and also employed a digital model of Spinosaurus to virtually test its buoyancy and stability in water. Their primary conclusion: largely due to the tall sail on its back, Spinosaurus would have struggled to swim in deep water. 

This is valuable data that helps refine our understanding of Spinosaurus, specifically by constraining the list of ways it could have obtained its fishy prey. Sereno and colleagues argue that Spinosaurus didn’t dive or pursue fish in open water, but their results don’t preclude the possibility that it spent most of its time around water or even in the water (indeed, there is still ample evidence that it did). 

I hope it’s clear that I have no qualm with the content of the paper itself. Instead, what drove me to start hacking at my keyboard today was the title: “Spinosaurus is not an aquatic dinosaur.” Within the paper, Sereno and colleagues define an “aquatic” animal as one “adapted for life primarily, or solely, in water with severely reduced functional capacity on land.” Bony fish, whales, penguins, and sea turtles are provided as examples. The authors go on to clarify that crocodiles and waterfowl do not meet the criteria for aquatic life. Hippos, sea otters, and pond turtles would also not qualify as aquatic based on this definition. The authors provide the term “semiaquatic” to cover these sorts of animals, and ultimately conclude that Spinosaurus itself was semiaquatic. 

Hippos spend most of their time fully or nearly submerged, but by the definition in Sereno et al. 2022, they are not aquatic. Photo by cloudzilla, CC BY.

I would argue that this use of the word aquatic is counterintuitive to all but the most dedicated specialists, and that its use in the title obfuscates the authors’ own conclusions. The definition of aquatic in common parlance is “of, in, or pertaining to water.” A hippo, for example, would be uncontroversially considered aquatic by most people, since it spends much of its time nearly or fully submerged. Therefore, I find no fault with the legions of people who saw the title and inferred that the authors were arguing that Spinosaurus did not spend time in or near water at all. Some might say that people ought to read the paper before drawing conclusions, but the title should be the first step on that journey. It certainly shouldn’t misrepresent the contents of the paper. This paper could have just as easily been titled “Spinosaurus was a semiaquatic dinosaur” and there would be no confusion. 

I don’t mean to call out this paper specifically, and I certainly don’t think the habits and habitat of Spinosaurus are of crucial public interest. However, I do see this paper’s title as emblematic of a bad habit among specialists, scientific or otherwise. It’s an insistence on using a technical definition for a word or phrase, even if that word or phrase is widely understood to mean something else. 

In a 2011 paper about barriers to public understanding of climate change, Somerville and Hassol provided a list of terms that have scientific meanings that are distinct from their popular meanings (below). Later, a crowd-sourced spreadsheet expanded the list. A case in point: for biologists, a mutation refers to any change in a gene. But for most English speakers, a mutation is inherently negative, and can have deadly consequences (or makes things really big really fast). A correct context for mutation is critical to understanding what evolution is, and how it works.

Table of frequently misunderstood scientific terms from Somerville and Hassol 2011.

In a particularly consequential example, the World Health Organization and other authorities avoided calling the COVID-19 virus “airborne” for well over a year. Why? In part, because they were adhering to a definition of airborne that excludes particles above a certain size, or which haven’t been demonstrated to linger in the air for a certain amount of time. A virus can be in the air, but not be technically airborne. Of course, anyone who isn’t an infectious disease expert would reasonably—but incorrectly—conclude that a virus that is “not airborne”  isn’t transmitted by breathing. Many factors contributed to the failure to contain COVID-19, but the use of counterintuitive jargon in messaging for a wide audience certainly did not help.

There is, I suppose, a certain nobility in declaring that “words have meaning,” and attempting to lead by example in their use. Likewise, there are certain words that have no common alternative, and must be introduced in order to communicate (synapsid and multituberculate come to mind). But new ideas stick better when they are built on existing knowledge—replacing ideas your audience already has is much harder. If you think the science you are communicating is important and worth knowing, why not meet your audience where they already are? Attention spans are short, so we need to use the limited attention we get wisely.


Fabbri, M., Navalón, G., Benson, R.B.J., Pol, D., O’Connor, J., Bhullar, B.S., Erickson, G.S., Norell, M.A., Orkney, A., Lamanna, M.C., Zouhri, S., Becker, J., Emke, A., Dal Sasso, C., Maganuco, S., Auditore, M., and Ibrahim, N. 2022. Subaqueous foraging among carnivorous dinosaurs. Nature 603:852–857.

Hone, D.W.E. and Holtz, Jr., T.R. 2021. Evaluating the ecology of Spinosaurus: Shoreline generalist or aquatic pursuit specialist? Palaeonologica Electronica 24(1):a03.

Ibrahim, N., Maganuco, S., Dal Sasso, C., Fabbri, M., Auditore, M., Bindellini, G., Martill, D.M., Zouhri, S., Mattarelli, D.A., Unwin, D.M., Weimann, J., Bonadonna, D., Amane, A., Jacubczak, J., Joger, U., Lauder, G.V., and Pierce, S.E. Tail-propelled aquatic locomotion in a theropod dinosaur. Nature 581:67–70.

Lewis, D. 2022. Why the WHO took two years to say COVID is airborne. Nature News Feature, April 6, 2022.

Sereno, P.C., Myhrvold, N., Henderson, D.M., Fish, F.E., Vidal, D., Baumgart, S.L., Keillor, T.M., Formoso, K.K., and Conroy, L.L. 2022. Spinosaurus is not an aquatic dinosaur. eLife11:380092.

Somerville, R.C.J. and Hassol, S.J. 2011. Communicating the science of climate change. Physics Today 64:10:48.


Filed under dinosaurs, education, opinion, science communication, theropods

2 responses to “Spinosaurus, aquatic animals, and jargon

  1. Excellent post getting at a fundamental issue for the sciences and scientists. Word choice is important but doing a better, more consistent job of explaining the meaning of critical terms as used in the sciences is also key (the word that comes readily to my mind is “theory”).

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