3. Hippopotamus
Don’t believe the hippos that you see in the animated movies, or in the live-action ones where they talk, unless they’re the hippotatomus from the “Cloudy with a Chance of Meatballs” sequel. Hippopotamus are not like that at all. Despite being herbivores, they are very territorial creatures and can also run as fast as 30 miles per hour to come after anything who goes into their territory. Every year, hippos are the cause of 3,000 human deaths too. How’s that for aggressive?