(Photo: Richard Conniff)
My latest for Takepart:
Not long ago in South Africa’s Soutpansberg, I watched a line of otherwise fastidious visiting high school students standing at a workbench happily sifting with their fingertips through specimens of excrement. Leopard excrement, to be precise. They were picking out hair, teeth, bones, horns, and claws, the undigested remnants of victims of predatory attacks—to be used in identifying the shifting dietary habits of local leopards.
The yuck factor aside, animal excrement, dung, scat, spoor, feces, poop, crap, or just plain shit is a topic of enormous importance for biologists and for biodiversity. It is of course also a source of many bad jokes, as anyone who has performed an owl pellet dissection in high school biology may recall.
But never mind that. Let’s start with the biodiversity, or rather, with the story of the honey locust tree. It produces long, leathery seedpods, which look completely unappetizing. But the woolly mammoth and a few other ancient megafauna used to gobble them up, inadvertently dispersing the seeds in their droppings. Then the megafauna went extinct, and the honey locust would inevitably have followed them–except that humans rediscovered the tree and widely dispersed its seeds (by hand) in cities and suburbs around the country.
Other fruiting plants have been less fortunate, and many are now on the path to extinction. New Zealand and Hawaii in particular are full of what botanists call “widow plants,” because extinctions have taken away the species they depended on to consume their fruit and defecate their seeds.
This form of partnership is common to a huge variety of plant species, which over the course of their evolution have come to depend on a bat, a bird, a fish, a gorilla, or even a crocodile to perform this vital service of dispersal by defecation. Beyond the coevolutionary richness of the connection Read the rest of this entry »