PSIMAaW_S, 20(2): 307-311, April 1979 307 Food-storing Behavior in Captive Squirrel Monkeys (Saimiri sciureus) BERNADETTEM. MARKIOTTand ERIC A. SALZEN University of Aberdeen ABSTRACT. Observations of food-storing in caged squirrel monkeys are described. Fre- quencies of storage and attempted retrievals increased with the introduction of novel objects. The type of storage site, its location and defense, all indicate hiding of food or favored objects to avoid stealing attempts rather than food or object play behavior. INTRODUCTION Over a period of 18 months we have observed a behavior in squirrel monkeys in our laboratory which we believe to be temporary food storage. This behavior was first suspected when pieces of food were repeatedly found on the top front edges of a cage housing three immature females [wild-caught, "Gothic-arch ''1), similar to those de- scribed by COOPER (1968) from Leticia, Colombia]. This group of monkeys was ob- served for several weeks in the spring of 1973. One monkey was seen breaking pieces of food-cake and storing portions on top of the cage or in an external water bottle holder. In both positions the stored food was out of sight from inside the cage. Having eaten the remaining pieces of food, she returned within 10 sec to 5 min to retrieve and eat the stored piece. The pieces of food regularly found on top of the cage were clearly ones that had been pushed beyond reach, or whose exact position had been forgotten. Similar behavior has been seen in other cages in our colony including those contain- ing immature males and adults of both sexes. It also occurs among adult females of the "Roman-arch" variety comparable with those depicted by COOPER (1968) from Iquitos, Peru. Observation has shown that when a monkey fails to retrieve a stored item successfully it may reach frantically about the surrounding storage area. Contin- ued failure may give rise to frustration displays of floor or trapeze shaking. (Through- out our colony of about 60 wild-caught squirrel monkeys trapeze shaking has devel- oped into a fine art, such that a freely suspended perch is shaken along its length so as to strike the sides of the metal cages with maximum audible effect.) Attempted theft of food from store by other monkeys frequently occurs and causes the owner to rush to the storage site and guard it. If the thief is successful, the dominance relationships of the owner and thief determine whether the loss is accepted or whether a chase takes place. Vocal threat and genital display may be given to a human who steals from the storage sites. We have attempted to determine whether this storing behavior was indeed intended to place food within physical reach but out of sight. 1) MACLEAN (1964) described the two common varieties of squirrel monkey in his laboratory based on the shape of the circumocular patch of white as "Gothic" or "Roman-arch" monkeys.