How Tiny Rodents Take the Place of Mastodons in an Ancient Ecosystem

Scientists believe that thousands of years ago, megafauna like mastadons helped disperse the enormous seeds of many plants. They'd eat the seeds, and then deposit them in their wanderings. But, with those creatures millennia dead, how do these plants still survive? In one case, it due to thievery-loving rodents.

In Panama, the black palm seeds are a target of the Central American agouti, a rodent about the size of a housecat. Far too small to disperse the seeds by eating and digesting them, the agouti is still very happy to hoard and eat them. But can these little creatures disperse the seeds as far and as effectively as an enormous animal like a mammoth?

By installing radio trackers on hundreds of seeds, researchers were able to follow their progress over the course of a year, and found that there's more going on here than just the agoutis stealing and eating the black palm seeds. Instead, the rodents will take them, then bury them. Later, they'll dig them up, move them, and bury them again. Or else another agouti will come by, steal the cache, and repeat the process. So while one animal might not move a seed very far, in concert they can disperse the seeds widely.

Some 35% of the seeds moved more than 100m, 14% survived the full year, and one seed was moved 36 times over 749 meters before finally being devoured. So while people don't generally think of rodents as being good at dispersing seeds in the wilds, this time they were good enough at the job to keep a venerable species from going extinct.

Photo by Geoff Gallice on Flickr