Wednesday 15 December 2010

Surinam Toad

Image: Arthur Chapman via flickr
That's not a leaf, that's a Surinam Toad! These creatures are strangely geometric and look a bit like the product of some not-particularly-impressive origami. They are remarkably flat, with a rectangular body and a triangular head. They are usually about 10 centimetres (4 inches) long, but they can also double this. Actually there are 7 species of Surinam toad, but they all seem to be quite similar to each other. Also they're frogs, not toads.

The name isn't totally inaccurate though; they are found in Surinam and pretty much the entirety of northern South America. They live at the bottom of the more dingy and murky swamps, where their dingy and murky colouration camouflage them. They must also rise to the surface for air.

Their back legs are large, powerful and webbed, perhaps this enables them to use brute force to get through the detritus of their habitat. The Surinam toad's eyes are tiny, putting me in mind of our very own Giant Salamander and suggesting that sight isn't of great importance to them. In fact, not only do they live in dinge and murk, they are also largely nocturnal. Instead we can look to their front legs and see that their fingers end in little star-shaped tips. It is these that are used to sense prey, from worms to insects to small fish.

It's pretty weird already, but it is in reproduction that the Surinam toad really kindles the torch of "What-on-Earth?"

Firstly, this frog has no tongue and can't croak. Instead, males put 2 and 2 together and make clicking sounds using the hyoid bone, the very bone its tongue would have been connected to. Once the female finds him, he gets on her back and holds on. She then kicks her feet and the couple slowly rise in the water and do a somersault. During this acrobatic manoeuvre she lays about half a dozen eggs, he fertilise them, catches them in his back legs and spreads them on her soft, spongy back. They do this repeatedly until she has around 60 to 100 eggs slowly sinking into her skin, which will grow around them until the eggs eventually disappear from view altogether.

Inside their mother's back, the young grow through the whole amphibian metamorphosis, from tadpoles to young adults. After 12 to 20 weeks tiny froglets emerge from their mother, less than an inch long but ready to make their own way in the world and otherwise identical to the adults.

Is that beautiful or disgusting? I don't know, but it's definitely remarkable.


Anonymous said...

I'm a slimy creatures kind of guy, and I've always found the Surinam Toad to be utterly revolting.

Seeing it's young burst out of its back makes you think of something out of Aliens.

Joseph JG said...

I know what you mean, Erik! Babies crawling out of your skin just doesn't look good!