Have thieving rodents saved tropical trees?
July 23, 2012
Big seeds produced by many tropical trees were probably once ingested and then defecated whole by huge mammals called gomphotheres, which dispersed the seeds over large distances. Photo by Christian Ziegler.
Big seeds produced by many tropical trees were probably once ingested and then defecated whole by huge mammals called gomphotheres, which dispersed the seeds over large distances. But hunters probably drove gomphotheres to extinction more than 10,000 years ago. So why aren’t large-seeded plants also extinct?
By attaching radio transmitters to more than 400 seeds, Patrick Jansen, a scientist at STRI and Wageningen University, and colleagues found that common rodents called agoutis buried 85 percent of the seeds in caches.
Agoutis didn’t eat many of the seeds. Instead, they moved them to new sites and buried them. One seed in the study was moved 36 times, traveling a total distance of 749 meters and ending 280 meters from its starting point. It was ultimately dug up and eaten by an agouti 209 days after initial dispersal.
Animals stealing seeds from one another caused frequent seed movement. Ultimately, a third of the seeds ended up more than 100 meters from their origin. By taking over the role of large Pleistocene mammals in dispersing these large seeds, thieving, scatter-hoarding agoutis may have saved these tree species from extinction.
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