Interactions 
Predatory-
Although adult hippopotamus’s do not have any predators besides humans, young hippos have predators that include humans, lions, crocodiles, hyenas, and leopards.
Hippopotamus often eat agricultural crops, which puts a strain on local economies. For this reason, locals kill them in order to protect their crops. Hippos are among the most dangerous African animals because they are very aggressive, have little fear of humans, they can outrun a man, and are unpredictable.
Hippopotamus is also a valued food source for many Africans. The meat is prized, along with the fat and the hide. The canine teeth are used for ivory, which there is an increased demand on because of the bans on elephant ivory.
Mutualism-
The Oxpecker bird eats parasites and insects off of the back of the hippopotamus. This protects the hippo from disease while giving the bird a meal.
Communalism-
When hippos walk from the water to their grazing grounds they create well-worn paths from the grasses back to a water source that help other animals to find water. When they eat the tops of grasses, they create “hippo lawns.” Gazelles and other animals benefit from the new green shoots that grow
The most important contribution hippos give is their waste. When hippos defecate in the water, their tail spreads the manure around. Small fish, snails, and other water animals eat the nutrient-rich dung to survive. In turn, these small animals are eaten by larger animals and fish, and usually end up being eaten by humans. Without hippos in Africa, there would not be as much of a food supply for humans.
Parasitic-
When warthogs re not available, the tsetse fly, Glossina morsitans, uses the hippopotamus as their main host. This fly will then bite a human and pass on the African Sleeping Sickness.
The hippos is also the main source of blood meals for Glossina brevipalpis and Glossina fuscipleuris. Twenty - thirty-six percent of their food can be taken from the hippo (Clausen 1).