tool use behaviors are observed in mammalian species where adults and their progeny have close ties. mother otters have one pup at a time and sea otter pups are dependent on their mothers for an average of 6 to 7 months. extremely young pups cannot swim or dive due to their natal fur coating, so they must be anchored to the mothers at all times. otter pups therefore receive undivided attention from their mothers for prolonged periods of time. this may have allowed young otters many opportunities to mirror the behavior of their experienced mothers and manipulate the objects that the mother otters were holding.