Domestic Cat
Even though cats tend to keep to themselves, they certainly have a mysterious side. It always seems like they’re up to no good, and they know more than we think they do. They’re responsible for more than 2.4 billion bird deaths every single year. If we were to switch birds with humans, then cats would be responsible for eliminating the human race twice over, every single year. Let’s keep these animals on our good side. Humans can also catch diseases from a cat bite, so if you are bitten by a domestic cat, take good care of cleaning the wound (via Best Life Online).