Hippos are not carnivores, they are herbivore animals. Most likely, the eating of corpse is the result of some violation of health or deficiency of basic nutrition, because the digestive system in these animals is not suitable for processing meat.
Interestingly, hippos do not chew grass, like, for example, cows or other ruminants, they tear the greens with their teeth, or pull it with their lips. Fleshy, muscular lips, the size of which reaches half a meter, is great for this fit. It is difficult to imagine what vegetation should be like to injure such lips.
In the pasture hippos always go out in the same place and return back to dawn. It happens that the animal wanders too far in search of food.
Then, upon returning, the hippopotamus can wander into another’s pond to gain strength, and then continues on its way to its basin.