Marcie Donnelly, Sr. Scientist, Clinical Services
Dept. of SALAR, Merck & Co., Inc


One of our Non-Human Primate’s (NHP) favorite enrichment devices is a hanging rope toy. The toy is made up of natural jute rope—12 to 14 inches in length and 3 inches in girth. The rope is secured by non-toxic glue into a PVC cap on each end, with a hook allowing you to place a clip for hanging either inside or outside of an animal’s cage. We use them primarily on the outside of our cages, where eventually the animals pull the rope completely apart. It’s been a great destructive enrichment for the monkeys. They spend approximately 1 week working on pulling the rope apart, at which time we throw it out. We have also used this enrichment device inside of our gang housing play cage, where the animals have been observed using it as a swing.

This device can be used for both Rhesus and Cynomologous monkeys; the cynos seem to enjoy this device more than most of the rhesus. Because cynos really seem to enjoy playing with various toys and being busy, this is a perfect device for them. They often spend hours pulling the rope slowly apart to form a nest in their cage, which we will leave in place for 2 to 3 days. We are lucky to have an understanding care staff that allows them to enjoy the “nests” they create with pieces of rope for a few days before removing them. So far, we have not had any clogged drains.

The benefit of the device is the amount of time the animals spend utilizing it. Since the animals spend hours focusing their attention on pulling the rope strands, this “destructive” enrichment component has been very effective for hair pullers and others with behavioral issues. Added benefits are no extra calories, as they would get from food treats, and, when finished, the device is simply tossed in the garbage. The impact on staff time is minimal: washing the ropes through a hot water only cycle, placing clips on the hooks, and hanging on the cages. The only negative aspect of the device is the price, approximately $22.00 per rope. But, when the animals work the rope for approximately 5 to 7 days, this makes it a better value, and when used with other non-destructive enrichment, the cost is not as high as you might think. We usually give these ropes out once every 1-2 months, so cost versus benefit is worth it for us.