How Do We Keep the Gorillas Stimulated?

Environmental and behavioral enrichment provides the gorillas with opportunities to engage in species-appropriate behaviors and provide them with choice or control over their environments. The caregivers provide many enrichment opportunities for the gorillas on a daily basis to keep them active, occupied and to enhance their welfare.

Our enrichment program involves creating and providing materials to promote positive mental or physical stimulation. Examples of behaviors we encourage include foraging, grooming, climbing, walking and running, nesting, and problem solving. Creating engaging activities requires astute observation of the gorillas’ natural behaviors and figuring out ways to either promote or enhance these behaviors. Caregivers use each gorilla’s personal behavioral repertoire to select the best activities for him or her. Ideally, an enrichment activity is neither too easy nor too complicated, as both can result in boredom or disinterest. Discovery, choice, and control are promoted through the presentation of enrichment through various modes:

Food-based Enrichment

Embedded, scattered, hung at various levels, presented at different times of day, varying diet items, etc.

Objects and Devices as Enrichment

Cardboard boxes and novel nesting material. Other items include books and magazines, sets of word & phrase cards, television, movies, painting and drawing materials, and children’s toys. We also re-use many recyclable items for enrichment, such as cottage cheese lids (for communication tools), boxes, containers, and bottles. And we use sturdy plastic tables, chairs, sandboxes and playhouses.

Behavioral Conditioning

Several of our caregivers/researchers conduct operant conditioning training with Ndume and Koko to enable us to easily shift them from areas, regularly weigh the gorillas, and do close-up monitoring of their health. The gorillas can choose whether or not to participate in these sessions, but a nice reward of nutritious treats usually finds them willing participants.

Habitat Design and Enrichment

Since gorillas in nature spend time on and off the ground, we factored this into the design of our habitats, providing complex, usable physical space with various levels, substrates, climbing and resting opportunities (ropes, tires, nets, platforms and shelves), and fixed objects (planters, concrete culverts, monkey bars, etc.). See our Facilities section for other examples of this form of enrichment.

Ndume enjoys a variety of enrichment structures in the large yard.