Hippopotamus Scientific name : Hippopotamus amphibious Type : Mammals Diet : Herbivore Average lifespan in wild : Up to 40 years Size : About 5 metersWeight : 1300 – 1500kgIUCN : Vulnerable Fun Fact One of the largest mammals on EarthThe name of hippopotamus means ‘river horse’ in Greek.Their unique skin needs to be wet for a large portion of the day. If a hippo is out of the water for too long, they can become dehydrated.