Do all mammals give birth?

If you search ‘mammals’ on the internet, you would find a long list of characteristics that make us (yes, we are mammals) unique, including characteristics such as being warm blooded, having backbones, four limbs, producing milk to feed young, etc. Some would even say that all mammals give birth, but is that really true?

I used to think that was until I met the echidna and the platypus at a zoo. These mammals lay eggs! Apparently, we are not the only ones who are surprised. Over a 100 years ago, scientists couldn’t believe their eyes either, and had to be convinced only after years of study.

So why do echidnas and platypus lay eggs? Experts think that they do this to survive in the environments they are placed in. For the platypus, living in both land and in water means that having eggs allow the parents (more like mother) to continue to eat while the children develop in the eggs. As for the echidnas, well… we haven’t yet figured out why they lay eggs.

Are they still mammals, then? Yes! Other than this unique way of reproducing, they have the all the other characteristics of mammals, including feeding their young with milk.

So, the next time your science teacher tells you that all mammals give birth, introduce them to the echidna and the platypus.