Saturday, March 30, 2013

Easter Platypus?

With Easter tomorrow, there are images of bunnies and eggs pretty much everywhere you look right now. And while many of these images are adorable beyond words...they make zero sense scientifically.

As a fan of adorableness and a fan of science, this has me torn. So I thought, for Easter, why not do a blog post with adorable pictures AND actual science? Best of both worlds!

Now, I'm sure everyone has some familiarity with why rabbits and eggs are used as Easter symbols. Springtime, fertility, yadda yadda yadda...I'm not going to rehash the quirks of Christian holidays and symbolism here. Instead, let's talk about the biology of these fuzzy, floppy-eared lagomorphs, and the dinosaur eggs we love to artificially dye and shove in pictures with them!

Now, rabbits do actually have eggs. Just like we do. But their eggs, like ours, aren't exactly large and don't have shells that we can dye fancy colors. They're kept internally, waiting for the male equivalent to come along.

What we usually think of as an egg is actually an unfertilized chicken egg, laid by a hen in a controlled environment. Or maybe you're more of a naturalist, and the first thing that comes to mind is a nest full of blue robin eggs. Regardless, I'm guessing when you hear the word "egg", you think of a bird egg. And that's fine! Bird eggs are eggs, after all. However, sometimes it can be fun to remember that eggs come in many shapes and sizes.

Fish and amphibians lay eggs that are squishy, like jelly, to allow water to seep in and out. Reptiles have a shell on their eggs. It's usually soft, but it serves its purpose--it allows for nutrients and water to be held inside the egg without getting out, and keeps the egg from needing to be laid in water. Dinosaurs have hard shell eggs, which allows for greater protection (especially when you consider the sheer size of some of the dinosaurs that would've been sitting on their nest!). Birds, which are dinosaurs themselves, have this type of egg as well. And it is this type of egg we associate with Easter.

Rabbits, on the other hand, are lagomorphs--a special type of mammal that generally is herbivorous and has four ever-growing incisors. They're well nestled in the family tree of placental mammals, making their eggs completely internal, as mentioned before. Definitely not what we think of when with think of the Easter Bunny and its basket of eggs. However, there are mammals that do actually lay eggs! Namely, the platypus and the echidna.

So what about the eggs of those odd mammals? Well, unfortunately for Easter egg hunt enthusiasts, platypus and echidna eggs most closely resemble soft-shelled reptile eggs rather than hard-shelled dinosaur eggs we generally stick with our rabbits for Easter pictures. Not exactly things we could dye and hide safely.

So what does this all mean?

It means that our Easter symbolism is a little wonky. The eggs we use with our rabbits are actually from an entirely different group of animals. If you wanted to get more accurate, you could use actual rabbit eggs, but they would be impossible to find on an Easter egg hunt, since they'd be microscopic. If you didn't care that it was specifically a rabbit ringing in the holiday, and just wanted a fluffy creature with large enough eggs to see, you could use an echidna or a platypus as the symbol instead. However, their eggs aren't hard-shelled and wouldn't dye as easy. Not to mention those animals live in Australia, where the seasons are opposite ours and therefore this "Spring" ritual would be entirely in the wrong time of year.

Moral of the story: Easter symbolism doesn't make a lot of scientific sense, and there's no easy way to make it more logical. But shh! I won't tell if you enjoy your adorable bunny pictures and have a Happy Easter anyway!

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