Weird animals: 17 of the most bizarre animals on Earth

Echidnas
Weird animals - the echidna penis. Image by Dr Jane Fenelon
The echidna has a four-headed penis, making it one of the world’s weirdest animals. © Dr Jane Fenelon
Which animal has the weirdest penis in the animal kingdom? Well, the echidna’s penis has four heads and looks like a foot. It’s also huge – measuring in at one third the length of the animal. Also known as the spiny anteater, the echidna is one of only two egg-laying mammal species alive today, the other being the platypus.