The petsuchos is a large endothermic reptile native to waters around the poles of Thanatos.
Petsuchos look just like a Terran albino crocodile, but they are much larger, are ectothermic and have flippers instead of limbs. At 230 feet long, the only animal bigger than it is the tusked leviathan. To adapt to the frigid temperatures, petsuchos have thick blubber. Their teeth are about 50-75 centimeters long.
Petsuchos live for about 150 years.
Petsuchos are known to be extremely intelligent, though not sapient. Their intelligence could be compared to that of a Terran ape or crow.