The study, published in the latest issue of Proceedings of the National Academy of Sciences, describes how several agoutis can transport large seeds for tropical trees in tag team-like fashion over long distances. Essentially one agouti steals the seed from another, moves it, and the whole thing starts all over again with another agouti.
(By the way, have you ever seen a close up of the face of these animals? It's a smile only a mother agouti could love. See the pic at the top of this page.)
But these rodents are survivors, and they help to explain why black palm trees have been around for over 10,000 years, even though the mighty now-extinct mastodon and similar beasts were thought to have been the tree's primary seed spreaders.
"The question is how this tree managed to survive for 10,000 years if its seed dispersers are extinct," Roland Kays, a zoologist with North Carolina State University and the North Carolina Museum of Natural Sciences, said in a press release. "There's always been this mystery of how does this tree survive, and now we have a possible answer for it."
The study found that the rainforest-dwelling agoutis hoard the palm tree's seeds like squirrels. Such huge seeds provide a lot of bang for the food buck, so the rodents often visit each other's caches and steal the coveted seeds. Each theft moves the seed around, which benefits the tree. The movement happens far enough away from the mother tree to create favorable conditions for germination.
"We knew that these rodents would bury the seeds but we had no idea that there would be this constant digging up of the seed, moving it and burying it, over and over again," explained Kays, a member of the Smithsonian Tropical Research Institute team. "As rodents steal the same seed many, many times, it adds up to a long-distance movement of the seed that one animal by itself could have never done."
Amazingly, one seed was buried 36 times before an agouti dug it up and ate it. About 14 percent of the seeds tracked in the study survived until the following year.