Deinosuchus: 167 Years of Getting the Terror Crocodile Wrong

This animal has been getting smaller for seventy years — not in life, but in the scientific literature. Fifteen metres in 1954. Twelve by 2002. Ten point six by 2005. Last April a team working out of Tübingen measured it again and got seven point seven. And in the same paper they took away the one thing everybody knew about it. For a quarter of a century the science filed Deinosuchus on the alligator side of the tree. It is not an alligator. It is not a crocodile either. It sits outside both, on a branch that leads to nothing alive. That reshuffle solved a problem that had made no sense for decades: why this animal turns up on both sides of the Western Interior Seaway, the shallow sea that cut North America in half. If it was a freshwater alligatoroid, it had no business over there. If salt tolerance is the ancestral condition — and the new tree says it is — then it simply swam across. The film is careful where the evidence is careful. Nobody has found salt glands in Deinosuchus, and salt glands leave no trace in bone; the claim rests on the shape of the family tree, and the authors propose a CT scan that has not been done. One skeleton gives three different lengths depending on which bone you scale from, and the spread is nearly double. And the famous bite-force number was calculated for an eleven-metre animal that the same field has since revised away. It is also not quite the dinosaur-eater of the documentaries. Count the bite marks and sea turtles outnumber dinosaurs by an order of magnitude — the teeth at the back of that jaw are short, round and built to crush shell. But one hadrosaur vertebra carries a bite mark that healed, and bone only heals in a living animal. That single specimen is the difference between scavenging and attack. Built on the peer-reviewed record: Walter, Massonne, Paiva, Martin, Delfino & Rabi (Communications Biology, 2025); Cossette & Brochu (Journal of Vertebrate Paleontology, 2020); Erickson & Brochu (Nature, 1999); Erickson et al. (PLOS ONE, 2012); Blanco et al. (Historical Biology, 2015); Mohler, McDonald & Wolfe (PeerJ, 2021); Taplin & Grigg (1981) and Taplin (Biological Reviews, 1988). W. J. Holland's original 1909 description is quoted directly. About the pictures: roughly three quarters of this film is archive imagery under free licences, and a fifth is real footage of living crocodilians — mostly saltwater crocodiles, the species whose salt glands the argument turns on. Five shots of Deinosuchus itself are drawn reconstructions, because the animal cannot be filmed, and two are diagrams. Full credits below. 0:00 An animal that keeps shrinking 1:31 Two teeth, filed under sea monster 2:58 The man who did not live to sort it out 4:16 Two vertebrae and a handful of armour 5:55 The skull built from a Cuban crocodile 7:56 Two holes nobody can explain 9:18 Teeth that did not cut 11:05 Armour that outgrew the animal 13:06 One skeleton, three answers 16:35 Fifty years, counted in rings 18:36 Two continents and a sea between 20:36 It was never an alligator 22:44 Salt 25:09 What we did not find 27:38 What it actually ate 29:18 The bite that healed 31:11 The roll 32:47 The number that lost its animal 34:57 Gigantism is a place, not an era 37:00 The one it never met 38:20 What we actually have 40:18 Smaller, and stranger Additional footage from Pexels (30 clips). Archive images (66) are public domain or CC0, via Wikimedia Commons. Images used under Creative Commons Attribution (77), via Wikimedia Commons: · LiterallyMiguel (16 images) — CC BY 4.0 · James St. John (9 images) — CC BY 2.0 · ノボホショコロトソ (7 images) — CC BY 4.0 · Brochu CA, Njau J, Blumenschine RJ, Densmore LD (3 images) — CC BY 2.5 · Scott D. Sampson, Mark A. Loewen, Andrew A. Farke, Eric M. Roberts, Catherine A. Forster, Joshua A. Smith, Alan L. Titus (3 images) — CC BY 4.0 · unknown author (3 images) — CC BY 4.0 · Amaury Laporte (2 images) — CC BY 2.0 · Donald Hobern from Copenhagen, Denmark (2 images) — CC BY 2.0 · FunkMonk (2 images) — CC BY 3.0 · Hanay (2 images) — CC BY 3.0 · JJ Harrison (https://www.jjharrison.com.au/) (2 images) — CC BY 3.0 · Jonathan Cutrer (2 images) — CC BY 2.0 · Rylan Bachman (2 images) — CC BY 4.0 · Source: Jonathan CutrerDerivative: User:MathKnight (2 images) — CC BY 4.0 · (c) Diogo Luiz, some rights reserved (CC BY) — CC BY 4.0 · Christophe Ferrante, Lionel Cavin — CC BY 4.0 · DagdaMor — CC BY 4.0 · David Ceballos from Madrid, España — CC BY 2.0 · Dick Culbert from Gibsons, B.C., Canada — CC BY 2.0 · and 15 further authors (15 images) — named in full in the pinned comment Full per-image attribution is in the pinned comment. Narration and score were created for this channel. 5 shots of the animal itself are drawn reconstructions, not footage; 2 are diagrams.