Airdate: Sep 20, 2007
Scientist: Christopher Birkinshaw
Seed Dispersal - Lemurs
Which animals plants use to disperse their seeds affects what the fruits of the plant look and smell like
ambience: Ring-tailed lemurs, Madagascar
In the forests of Madagascar, the seeds of many trees and plants have evolved to be tailor-made for lemurs. What's a lemur? Stayed tuned. I'm Jim Metzner, and this is the Pulse of the Planet.
They look a little bit like a cross between a raccoon and a monkey. The tree-dwelling primates known as lemurs are the primary seed dispersers in the forests in Madagascar.
"Lemurs are good seed dispersers because they can swallow really big seeds - up to maybe four centimeters long. Which is really amazing when you think of an animal a fraction the size of a human, you know, that’s pretty impressive."
Christopher Birkinshaw is with the Missouri Botanic Garden.
"Plants are quite cunning in making lemurs swallow seeds of this size. Because, of course, lemurs, if they could - they would spit these seeds out. But, in fact, if they want the fleshy reward, which is surrounding the seed, they’re forced to swallow the seed, because often the flesh is very difficult to separate from the seed. You can’t just nibble off the flesh and then spit out the seed."
So lemurs digest the fleshy fruit, but the seed passes through them undigested and is thus dispersed through the forest.
"In Madagascar we can clearly see the stamp of lemurs on the characteristics of the fruits and seeds of plants. The color of fruits tend to be dull colors, like green, or brown, or dull orange, and that’s because lemurs don't have good color vision.
"What lemurs do have, on the other hand, is very good sense of smell. And so rather than trying to attract lemurs by having colorful fruits, the trees had evolved dull-colored fruits, which were scented."
We'll hear more on Madagascar in future programs. Pulse of the Planet is made possible by the National Science Foundation.