With perhaps baboons as jockeys.
Two species of animals that look kind of funny but are very dangerous.
In the water, hippos are psychotic defenders of their territory.
They can literally cut a full grown crocodile in half with one bite. I saw a nature film once that showed multiple episodes of crocs swimming for their lives in every direction when hippos entered the water.
On land, hippos are lot more vulnerable, especially to carnivores that hunt in packs.
Hippos usually wander inland at night to forage, especially in agricultural areas. If humans have the bad luck to get between a hippo and the water, the hippo will instinctively try to trample the human, which results in dozens of human fatalities every year.
About 10 years ago, biologists determined that the closest living relatives of hippos are...wait for it...whales!
