Animals facing changes in food abundance over the year can either defend an area large enough to always have enough food, or fight to expand their territory when times get tough.

By the start of the dry season in Panama there is little new food for agoutis, and they are largely living off the seeds they have hidden in caches earlier in the year.  Then Dipteryx starts fruiting, offering a fresh fruity exterior with a nutritious nutty inside.

This is the time of year where you can see hoards of agoutis hanging out under Dipteryx trees, and some have speculated that they give up on their territoriality in this time of year and all fatten up on Dipteryx like grizzly bears at an Alaskan salmon stream.

Annemarie found this wasn’t exactly the case.  Agoutis were 5 times more common underneath Dipteryx trees than other locations, but radio-collared agoutis didn’t abandon their territories to camp out under these trees.  Some animals would boogie out of their normal range for a quick breakfast at a nearby tree, but returned to spend most of their day back home.  The degree to which they changed home range depended on how many Dipteryx there were nearby, and also the local density of Astrocaryum trees, their primary cache fruit.  One agouti seemed to do just fine without any Dipteryx in his home range at all , presumably living off the numerous seeds he cached earlier in the year.

Congratulations to Annemarie on a very successful thesis!