Feeding ecology and diet

Pacas eat fruits of understory trees and shrubs and fallen fruits of taller trees. They have also been recorded as eating leaves, buds, flowers, and fungi. Studies in Costa Rica iden-

A paca (Agouti paca) eating fallen fruit. (Photo by Nick Gordon/Na-turepl.com. Reproduced by permission.)
The paca (Agouti paca) is a very good swimmer. (Photo by Frans Lant-ing/Minden Pictures. Reproduced by permission.)

tified 33 plant species consumed by pacas. Pacas play a major role in seed predation and in seed dispersal. Home ranges may have an activity core that centers on a cluster of fruiting trees. This center shifts as fruit availability changes. Pacas rarely use their forepaws to manipulate fruits. Accordingly, they are unable to exploit some types of fruits that the smaller agoutis manage to penetrate through the ability to keep gnawing at a chosen spot while dexterously manipulating the fruit in their forepaws. However, pacas do have powerfully muscled jaws and strong teeth; they are even able to break open the species of the very woody hard-shelled fruits of Shelia palms. In addition, pacas browse on seedlings and nibble flowers. The remains of ants and caterpillars have been found in their feces and stomach contents. It is not known if these were ingested intentionally or accidentally.

The loss of pacas in Los Tuxtlas, Mexico is believed to be one of the key reasons for a two-thirds drop in plant diversity in this rainforest remnant. Unlike agoutis, pacas can store fat to see them through seasonal slumps in fruit availability. Consequently, they have less of a need to cache seeds against hard times. Ever alert for predators, pacas like to eat seeds in the darkest possible place (such as a burrow or a hollow log). Pacas disperse seeds by active transportation in their stomachs and then voiding them in their feces, and (more rarely) by forgotten caches and accidental dropping of fruits held in cheek pouches. However, they are less efficient dispersers than agoutis. Competition with agoutis is avoided by different cycles of activity and slightly different food preferences. Pacas supplement their diet with mineral-rich soil from salt licks. Like rabbits, pacas practice caecotrophy, the ingestion

Pacas (Agouti paca) will sometimes take to the water when threatened. (Photo by © Partridge/OSF/Animals Animals. Reproduced by permission.)

of specially produced fecal pellets from which they absorb protein and carbohydrates synthesized by microorganisms living in the caecum, with a second passage through the digestive system. These moist soft pellets are different from the hard dry pellets that are fully excreted, and are a way by which the animal gets an additional bonus of nutrients from their food. Caecotrophy occurs in the burrow when the paca is asleep in its characteristic posture of mouth close to the base of its tail.

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