The Web of Life (84-2) Survival by Theft

 Survival by Theft

Seed dispersalĀ is essential to many plants and trees for population survival. Fruit is a common incentive to facilitate animals spreading seeds.

The Neotropics (tropical Central and South America) are rich in woody species that bear large-seed fruit. 10,000 ya, megafauna, such as mastodons and gomphotheres, effectively scattered seeds by defecating far from the source of their meals. The extinction of these megafauna by human hunting carried the risk that these tree species would also go extinct. Yet several survived.

AgoutiĀ are a rodent endemic to the Neotropics, related to guinea pigs, but more rat-like. Macaws and agouti are the only species known that can open Brazil nuts without using tools; a feat that takes strength and exceptionally sharp teeth.

Like squirrels, agouti hoard food in numerous small, buried stores. Like rats, agouti are wily thieves, readily raiding caches that others bury. By repeated theft and recaching, a seed may be moved many times; sometimes 30 or more.

Not all cached seeds are eaten. 14% survive to germinate the next year.

Germination is no guarantee of a good life. It is in a plant’s interest of legacy that its seeds are not dispersed to a location where seedlings will face competition from their own kind (conspecifics).

An agouti tends to move its seeds away from conspecific trees, as it figures a more remote location helps avoid pilfering by other agoutis. Such strategic thinking benefits an astute agouti and the seeds it caches.