If a magical being pops into existence in front of you and demands that you choose a non-human animal into which you will be reincarnated, one of the first things you should consider is: how many babies does the species have, and how big are they? If you want a good shot at surviving past infancy in your second life, you will want to select a species that has just a few, big babies. Elephants are a good option, with their single giant offspring; ditto whales. Large sharks are a solid possibility, often birthing just two large babies at a time (but you’ll want to be careful that you don’t pick a species—such as the sand tiger shark—in which many embryos are formed in the uterus, and then all but two are eaten by their siblings before birth).

You will most certainly not want to choose to be a species whose offspring look like this:

Cope’s gray treefrog pair with eggs

Those many, tiny eggs suggest that each one has a very low chance of survival. Let’s take a closer look.

Add some light…

If you think these eggs look like hot cross buns or dumplings, you’re essentially right: lots of animals would consider them a tasty snack. The eggs are surrounded by a protective gelatinous mass, but armor made of jelly will only get you so far.

Seriously, mom, abandoning us with some jelly is the best you can do?

Being a Cope’s gray treefrog egg is a perilous proposition. Good news, though: you only have to survive as an egg for five days! Then you get to hatch out and be… a tiny swimming dumpling.

If you hide in cover and eat as much as you can, there is just a slim chance that you might survive long enough to get too big for most of your fellow denizens of the pond to eat.

Success! I made it!

But don’t relax just yet. That pond, full of reeds and muck and darting worms, is as dangerous to you the frog as an African savannah is to a gazelle.

Here there be lions.

Garter snakes will eat you. Bigger frogs will eat you. Even some beetles will eat you. And instead of hiding quietly like a sensible amphibian, you will sit out in a prominent place and announce your presence for all you are worth, in the hopes of attracting a female.

By the time we see frogs in the lab, they are already survivors, having made it through egg-hood and tadpole-ness to the finish line of adulting. Their past experiences are largely a mystery to us—with a few exceptions. You know that brilliant, lovely skin of theirs?

That skin shows scars.

This frog had a close call at some point—maybe with something clawed?

This might be an old bite wound.

This frog appears to have lost and regrown large patches of skin. Ouch!

Not all the injuries we see have healed.

This frog lost most of his left hand. Frogs are very good at regrowing things, though: in a few months he may have a full hand again.

This frog is less fortunate, having loss the use of her right arm but not the limb itself, and so having no chance of regrowing a functional one.

Yet every frog we see has come to us because they managed the ultimate treefrog achievement: not only surviving to adulthood but finding a mate. Some of them hop a little more easily than others, but all are success stories. When, after a few days of observation, we release them back into the pond, we are rooting for their continued success in this dangerous world.

This crooked-backed, much-scarred female has seen some stuff.