Chimp Enrichment: A Blanket Statement

If you have visited the chimps in the African Forest, chances are you’ve seen them toting around blankets or resting with them in the hammocks.  “Why in the world would a chimpanzee have a blanket?”, you may be wondering.  Well, because they like them, that’s why!  Our chimps here at he Houston Zoo grew up having blankets to sleep with and to play with, and this affinity has carried over into adulthood.  Blankets are comfy, they smell nice (the keepers launder them regularly), they keep you warm in winter and sometimes, they have treats hidden inside them.  Who doesn’t enjoy a blankie?

Annie (on the ground) and Sally (in the hammock) enjoy their blankets. Photo by Ron Santos.

The chimps don’t have an attachment to any particular blanket, they just want them to be clean and dry.   The keepers make sure there are enough blankets for everyone that wants one, then pick them up for washing when the chimps lose interest.  Sometimes, just to make it interesting, the keepers hide food in a folded blanket, or spread food out on it for a picnic.  A dash of perfume or essential oils makes it even more intriguing.

Blankets are just one of the many types of enrichment we use to keep the chimps engaged and to encourage the expression of  natual behaviors.  “What kind of ‘natural’ behavior can a blanket encourage?”, you are asking yourself.  Chimpanzees, as well as other apes, are nest-builders.  Meaning that whenever and wherever they rest, they will build a “nest” for themselves out of whatever materials are at hand.  In the wild this may be leaves, branches, grasses or even entire small tree limbs.  Often these nests are high in trees to avoid predators.  They rarely use the same nest twice and, except for infants, each chimp makes his or her own nest.  Can you think of a better material for making a nest than a blanket?  Me neither.

Naps and blankets go together like peas and carrots. Or bits of broccoli in this case. Willie napping photo by Ron Santos.

“So what other types of enrichment do the chimps get?”, you are now asking.  You certainly are full of questions today!  Well, since this is one of my favorite subjects, I’ll tell you.

One of the most remarkable discoveries in the field of animal behavior was the observation in 1960 that wild chimpanzees make and use tools.  Previously, it was thought that only human beings were capable of this.  There are many ways in which chimps use tools, but one of the most well-known is using grass stems or sticks to “fish” for termites.  (Click this link for more info on termite fishing.)  Our chimps are not used to eating termites, but they do love a sweet snack, so we load our termite mound replica with semi-liquid food that might be sweet one day, or savory the next.  We try to keep it interesting and different each day.  The only way the chimps can reach their treat is to fish for it using whatever they can find, usually bamboo sticks.  This built-in innovative enrichment device never fails to captivate chimpanzees and guests alike.

Chimps using the termite mound replica. Clockwise from the top: Mac, Lulu, Willie, Riley and Annie. Guests can see what the chimps are fishing for inside the mound. Photo by Ron Santos.

Being intelligent and curious, chimps love to investigate and manipulate objects.  They especially love cardboard and paper that can be torn up and rearranged to their liking.  Cardboard boxes can hide food or treats and then be used for nesting when the food is gone.  Big ones like refrigerator boxes make great forts. (I bet you’ve done this, too, haven’t you?) This type of enrichment is usually reserved for the off-exhibit holding area as it can create quite a mess.

Not all enrichment has to encourage “wild” behaviors; Sometimes it is just something the animal finds interesting and fun. For great apes especially, one such behavior is painting.  Keepers generally hold the canvas with paint on it and hand the animal a paintbrush. Participation in this activity is completely voluntary, but we find the chimps rarely turn down the opportunity to smear the paint around on the canvas… and then eat some of it.  Don’t worry, it’s all non-toxic.  And apparently delicious, though I have not tried it myself.

Charlie working on his masterpiece. And having a paint snack. Bonus!                                               Yet another great photo by Ron Santos.  Thanks, Ron, for all the wonderful pics!
For chimps, though, the ultimate enrichment is other chimps.  By nature chimpanzees are gregarious and have incredibly complex social lives.  Daily, they must negotiate their relationships with each other: cementing friendships and alliances, squabbling over food or toys, resolving conflicts and angling for a higher position on the social ladder.  Our group of five males and five females are incredibly interesting to watch and learn about.  They may just be a great source of enrichment for you!
A gratuitous Willie photo. Taken by, you guessed it, Ron Santos.

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