Rainforest Rodents Risk Their Lives in the Mornings: Ocelots Chow Down

It turns out that the early cat gets the rodent. Scientists have discovered that hungry rodents that wake up early are much more likely to be eaten than rodents that are getting plenty of food and shut-eye in the rainforest.  That's a bit of incentive to sleep in.

In order to learn a bit more about animal behavior, the researchers equipped agoutis, common rainforest rodents, with radio collars. They also equipped ocelots, their feline predators, with similar collars. This allowed the scientists to track the animals 24/7 with an automated telemetry system.

"Agoutis eat tree seeds. Ocelots eat agoutis," said Patrick Jansen, one of the researchers, in a news release. "Where food is hard to find, agoutis spend more time foraging and are more likely to be eaten by an ocelot."

The researchers found that during the day, thousands of agoutis were active. However, very few ocelots were out and about. Around sunset, though, agoutis sought the shelter of their burrows and ocelots became increasingly active. Around sunrise, the number of ocelots dropped again. The researchers also kept track of the agoutis that died, noting when they stopped moving and using video cameras at the scene to allow them to determine if a predator returned to eat the remains.

In the end, the scientists found that 17 of 19 dead agoutis were killed by ocelots. In addition, most of these kills happened just before sunrise and just before sunset--a time when relatively few agoutis were active.  What was more interesting was the fact that agoutis in areas with less food left their burrows earlier and entered their burrows later, which made them perfect prey for ocelots.

"We knew that hungry animals tend to take more risks, but this is the first study to so thoroughly document the behavior of both predator and prey," said Jansen in a news release.

Currently, the researchers plan to see what the differences in predation risk mean for seed dispersal by agouti. This could further tell scientists about how this rainforest ecosystem functions and could allow them to better understand how changing conditions might impact it in the future.

The findings are published in the journal Animal Behavior.