The importance of providing woodchips for hygienic purposes has been established by Chamove et al (1982), and the provisioning of bedding materials is encouraged for environmental enrichment by Bayne (1989). At the Primate Foundation of Arizona (PFA), we provide bedding materials along with woodchips for these reasons and to encourage natural wild chimpanzee activities, such as foraging, nesting, and tool use.

When forage materials are provided, bedding materials, such as straw or shredded newspaper, along with woodchips increase the amount of time the captive chimpanzee spends in search of forage materials. We furnish chicken scratch as a forage material because it was found to increase foraging time, over such items as popcorn (Grief et al 1992). The pieces are small and disappear into the bedding material, while popcorn remains on top. We found it to be cost effective, easy to store, and our chimpanzees find it highly desirable. The chimpanzees can be seen foraging throughout the day with a single day's allotment of chicken scratch.

Another behavior that can be seen at PF A through the day is nesting. Continuous access to bedding materials allows for nest building whenever the chimpanzee desires to make a nest. For night nests, the chimpanzees are provided with fresh newspapers late in the afternoon. Whether this be the normal time for evening nesting or the novelty of the fresh materials, most chimpanzees can be seen preparing a new nest immediately following the receipt of the newspapers.

We provide some sort of bedding for all of our chimpanzees. The nursery infants are provided with blankets, while most of the chimpanzees receive straw, a few are supplied with shredded paper. Mothers who had been observed sticking straw in their infant's ears are given paper. In addition, an adult male, who has had a history of placing straw in his own ears is provided with shredded newspaper. Straw is preferred by management because it is more economical and cleaner. Paper, for the few above mentioned, is provided by our office paper shredders and newspapers brought in by staff.

The desire and ability for tool use is seen at a very young age in PFA's chimpanzees. We encourage this natural activity by giving the chimpanzees the means by which he/she can make and use tools. Although straw and shredded paper may seem somewhat limiting, multiple uses of both have been observed. There is the standard "fishing." This is observed when monkey chow crumbs are "fished" from the feeder with a piece of straw from the bedding. They also spend a great deal of time filling other enrichment objects, such as plastic jugs, cardboard tubes, and boxes with the bedding material and woodchip mixture. The chimpanzees who have access to the shredded paper, make sponges and then wipe off walls and benches. Those who have straw make brushes, by taking a hand full of straw, then using it to clean their hair by stroking the hair with the straw.
Where possible, the provision of bedding materials, provides chimpanzees enrichment that is beneficial and interesting while still being cost effective.

Bayne, K Environmental Enrichment Alternatives For Laboratory Nonhuman Primates. Animal Care and Use in Biomedical Research. Regulations, Issues and Applications. J. Driscoll, Ed. 91-102, 1989.

Chamove, A.; Anderson, J.; Morgan-Jones, S. and Jones, S. Deep Woodchip Utter: Hygiene, Feeding, and Behavioral Enhancement in Eight Primate Species. International Journal of Animal Problems. 3(4):303-318, 1982.

Grief, L; Fritz, J.; and Maki, S. Alternate Forage Types for Captive Chimpanzees. Laboratory Primate Newsletter. 31(2):11-13,1992.