tool use behavior is presumed to be learned, rather than innate, behavior. otters that use stones to open prey do not use stones every time they need to manipulate their prey. crabs, for example, can be ripped apart by the forelimbs and then eaten. otters will store a stone in the pouch of skin under the arm to eat prey with both forelimbs, such as crabs, and then retrieve the stone at a later instance. this seems to imply, "an anticipation of use that goes beyond the immediate situation". if a stone appears to be particularly good for opening one food item, it will be kept for several others. in an observation of an otter in point lobos state park, it was seen than one otter ate 44 mussels in one feeding episode and only used six stones.