A Dentist's Worst Nightmare

You are staring a common hippopotamus in the mouth. Their groups, called schools, are female dominated. This is surprising, since they spend so much of their day wallowing, fighting, and eating - activities found more frequently in human males.

This open-mouth posture is not a yawn, but a sign of aggression and a willingness to fight. These beasts are responsible for more human deaths in Africa than any other animal (save virus-bearing insects) - because they tend to stampede, and can run at a quick clip.

Their name means 'river horse.' If 'land' horses looked this ugly, I think human agricultural and military history would be quite different - certainly the images of the American cowboy or the knight on horseback wouldn't be the same.

Photo courtesy: animals.timduru.org.