Height: 8 feet
Weight: 2.6 tonnes
- Adult (both sexes): Varies from rusty brown, to a dull green and gray. The top half of the body is black to very dark brown with a white underbelly. The horns and facial plates are also black, but have color flushing patches.
- Juveniles: Similar to the adults, but lacking horns and well defined facial plates; their color patches are inactive unless under heavy stress
Diet: Horsetails, ferns, fallen fruits, aquatic plants, small to medium animals, carrion.
Preferred Habitat: Swamps, Jungle, rivers; and wetlands. Estemmenosuchus typically only moves far away from water at night, ranging over most of the island during the darker hours.
Social Structure: Small groups of females led by a dominant male, other males are solitary or form bachelor groups.
Estemmenosuchus is a large, hippo-sized mammal-like reptile with very compact, powerful build and a semi-sprawling gait. It can be recognized for its massive bony branched protuberances (or facial plates) which grow upwards and outwards from its head - somewhat similar to the antlers of a moose - as well as additional protrusions which grow from its cheeks. These are larger in males than in females, while they are absent in juveniles.
Male Estemmenosuchus also have a stocky horn on the middle of their snout, two thirds of the way down the skull, up to 8 inches in length. The head itself is massive and the mouth is wide, containing large, sharp incisors and long canine teeth which interlock when the jaws are closed. These canines are self-sharpening.
Estemmenosuchus’ lifestyle is similar to that of a modern hippo. It spends a majority of time submerged in water during the day, and will become active during the early morning and evenings to graze on vegetation or to scavenge carrion on dry land. It can move about in the water by either swimming or walking on the bottom, able to remain submerged for roughly 10 minutes if not moving frequently. It can also sleep with its body under the water and its snout resting just above the surface.
Males are particularly territorial, and will defend their land as well as any females within it from other males. Males fight similarly to hippos in which they spar with both jaws wide open, inflicting deep wounds with their canine teeth. Females are more docile than males unless protecting young. Females lay eggs on dry land, in mounds similar to the nests of crocodiles. Females remain close by in the water, ready to defend their nests should they become threatened. Because of their herding behavior, females frequently nest very close to eachother, or share a nest to increase protective efficiency.
While not quite as large as Muerte’s mammalian mega-herbivores, Estemmenosuchus makes up for this with sheer veracity in combat. A charging, snarling Estemmenosuchus is enough to give all but the largest predators second thoughts about attacking this animal. Because of its size, power, aggressiveness; and nocturnal habits, adult Estemmenosuchus have little to fear from predators, although their calves sometimes fall prey to predators such as Smilodon, Thylacoleo; and Titanoboa.
Estemmenosuchus calls consist of crocodile-like bellows and loud, hoarse roars.