Proterosuchus was a mid-sized quadrupedal reptile with a sprawling stance that could reach a length of up to 3.5 meters (11 ft).

The lifestyle of Proterosuchus remains debated; it may have been terrestrial or it may have been a semiaquatic ambush predator similar to modern crocodiles.

They were isodont, or all equal in size and shape, in adult individuals, but in juveniles, the teeth were less strongly curved in the back of the jaw.

[2] The lower jaw bears a small external mandibular fenestra, another characteristic of archosauriforms and their closest relatives.

[9] Allokotosauria Rhynchosauria Boreopricea Kadimakara Prolacerta Teyujagua Tasmaniosaurus Archosaurus Proterosuchus Sarmatosuchus Cuyosuchus Erythrosuchidae Eucrocopoda (includes Archosauria) Proterosuchus is an early member of Archosauriformes, which also contains crocodilians, pterosaurs, and dinosaurs, including birds.

The orientation of its ear canals suggests its neutral head posture had the snout angled upward, which would have raised the nostrils high enough for the animal to breathe while largely submerged.

[26] However, the utility of the orientation of the semicircular canal in determining head posture and habitat preference has been challenged.

[28] However, Proterosuchus lived near the Antarctic Circle, so its mesopic vision may have instead been an adaptation to the highly seasonal day lengths it experienced.

Due to its low-sensitivity hearing, Proterosuchus probably did not rely heavily on vocal communication and may have been relatively solitary.

Based on the size of its olfactory bulbs, Proterosuchus had a strong sense of smell, similar to that of modern crocodiles.

However, its olfactory bulbs were not as large as those of its relative Tasmaniosaurus, suggesting different habits and potentially a more aquatic ecology in Proterosuchus.

[31] Its metabolic rate was lower than most other crocopods, except for the ectothermic phytosaurs and crocodilians, which may have been an adaptation to a crocodile-like predatory strategy.

It probably reached sexual maturity within a year, at roughly two-thirds of its maximum adult body size.

[8] Proterosuchus fossils are found in the Lystrosaurus Assemblage Zone of the Beaufort Group in South Africa.