Reclassification of Deinosuchus

Recent studies have challenged the traditional classification of Deinosuchus, a large prehistoric reptile that lived in North America between 82 and 75 million years ago. Previously thought to be a giant alligator, new research suggests it may belong to the crocodilian lineage, retaining a saltwater tolerance from its ancestors. This reclassification has sparked debate among paleontologists.

Size estimates of Deinosuchus

Deinosuchus is estimated to have measured between 7.7 and 10 meters in length, with some individuals possibly exceeding this range. Recent studies by an international team led by the University of Tübingen suggest that the species Deinosuchus riograndensis was around 7.7 meters long, though some individuals may have been "about 8 meters or more." Another species, Deinosuchus schwimmeri, found in Mississippi and Alabama, is known for its unusually large teeth, described as "the size of bananas."

Habitat and predatory behavior

Deinosuchus lived alongside dinosaurs in rivers and estuaries across North America. Its immense size and powerful jaws made it a top predator, capable of attacking large animals that came too close to the water. A study published in April 2025 in the journal Communications Biology provided a more precise classification, placing Deinosuchus outside the alligator lineage. Its saltwater tolerance may have allowed it to cross the Western Interior Seaway, a vast inland sea that once divided the continent.

Movement and ecological dominance

Biomechanical simulations from October 2025 indicate that large crocodilians like Deinosuchus could not lift themselves off the ground. Instead, they moved by dragging their bellies, a slower and less agile method compared to smaller relatives. Despite this limitation, Deinosuchus ruled its aquatic environment for millions of years, likely relying on ambush tactics in shallow waters rather than speed to capture prey.