Primarily herbivorous, gorillas eat the leaves and stems of herbs, shrubs, and vines. In agricultural areas, they may raid farms, eating and trampling crops. They will also eat rotten wood. The fleshy fruits of close to a hundred seasonally fruiting tree species make up a large part of their diet. Gorillas get some protein from invertebrates found on leaves and fruits. In the wild, gorillas spend much of the morning and evening feeding in a small area. However, since lowland gorillas rely heavily on fruit, they sometimes travel up to about a half mile or more in search of fruiting trees.
Although they don’t have to travel far at the San Diego Zoo Safari Park to find a meal, the gorillas do get a wide variety of fruits, vegetables, low-carb biscuits, and browse (plant material). Browse varieties include acacia, ginger, bamboo, grewia, tipuana, eugenia, and ficus, all grown at the Safari Park. The items are all offered on a rotating basis so they don’t get the same food every day. The gorillas are fed five to six times a day, and food is distributed throughout their bedrooms and exhibit to encourage foraging.
Two of their meals are fed inside the night bedroom. Although the keepers do not go in the bedrooms with the gorillas, we do have limited contact through the bars. This allows us the opportunity to develop relationships with each of the gorillas. Hand feeding creates a bond with each gorilla and facilitates health assessments and distribution of medications. Operant conditioning, a training technique using positive reinforcement and rewards, is also used to further enhance the rapport between the gorillas and the keepers. The gorillas enjoy the individual attention!
Each day the gorilla troop at the Safari Park consumes approximately 5 pounds of fruit (such as apples, oranges, pears), 43 pounds of greens (such as kale, romaine lettuce, spinach), 16.5 pounds of veggies (such as jicama, onions, broccoli), and 7 to 10 branches of browse. Snack food is offered in limited quantities on a rotating basis and may include air-popped popcorn, sunflower seeds, tamarind pods, raisins, prunes, applesauce, peanuts, and popsicles made with fruit juice/nectar.
Peggy Sexton is a lead keeper at the San Diego Zoo Safari Park. Read her previous post, Introducing Gorillas to a New Troop.