4. Hippopotamus
Source: boredpanda.com
It’s humongous, it’s semiaquatic, it’s mostly herbivorous. Of course – it’s a hippo! Hippos are one of the largest mammals of sub-Saharan Africa. Despite of looking friendly, they’re very agressive and there have been reported attacks of hippos attacking boats. In one such attack, 13 people were killed. Their numbers are waning mainly due to loss habitat.