The time of the giant amphibians was supposed to have ended during the Permian period...and yet Koolasuchus managed to evolve millions of years after their hayday. The last of the giant amphibians, this salamander-like creature lived like a crocodile, ambushing fish and even small dinosaurs from rivers and lakes. Koolasuchus is among the largest amphibians to ever live, with the only amphibian alive today even close to that size being the Japanese giant salamander.

Basic info

Meaning of name: Koolasuchus means "Kool's crocodile", named after the paleontologist Lesley Kool.

Time of existence: Koolasuchus lived during the early Cretaceous period, 137 million to 105 million years ago.

Diet: Koolasuchus fed primarily on fish, although they also fed on the small dinosaurs that lived around them.

Threats: Koolasuchus was most likely seen as prey by crocodiles and larger dinosaurs.

Size: Koolasuchus grew to 9.8 feet.

Attributes: Much like a crocodile, Koolasuchus was an expert at ambush hunting, lying in wait in the water for prey to come to it. They also would move into the forest and find a hot spring to sleep in, hibernating until spring. Like other amphibians, they were able to go on both land and in water.

The full body of the strange Koolasuchus

Appearances in the Walking with... series

Walking with Dinosaurs

Episode 5-Spirits of the Ice Forest

Koolasuchus plays a recurring role in the episode. At the beginning of the episode, a Koolasuchus is seen awakening from it's hibernation and notices a dead Leaellynasaura in front of its pond. It submerges briefly before lunging out and dragging the dead dinosaur to the water, where it will eat it. Later, when spring fully hits, a Koolasuchus (possibly the same one from the beginning) is seen emerging from its pond and breathing, before swimming to the shore and walking onto the bank. He is spotted by the Leaellynasaura sentry, but he proves no threat. He climbs up a slope to journey 200 meters to the river. Once he finally reaches the bank, he travels to the river, and finally gets into his summer home. We are told that in most of the rest of the world, Koolasuchus has been outcompeted by crocodiles, but in the South Pole, it gets too cold for them, so the last of the Koolasuchus thrive here. He takes a brief breath and swims underwater with a second Koolasuchus.

Two Koolasuchus swimming underwater

Koolasuchus reappears during the summer segment, where he is seen from underwater stalking a young Leaellynasaura that wandered down to the river. He retreats underwater and attempts to ambush the little dinosaur, but fails, as the young dinosaur successfully evades it, and he retreats back underwater. Koolasuchus makes one final appearance when autumn hits, where upon sensing the change of season, he crawls out of the river, and drags his bulk back into the forest, in search of a place to hibernate during the winter.