	During long-term studies to record behavior, it is frequently recorded that some, individual otters do not use tools at all. Instead, these otters target soft-bodied prey like fish, or urchins which can be ripped apart with the forelimbs. Among tool using otters, up to 21% of the day can be spent engaging in tool use. In a study conducted from Alaska to Southern California, sixteen otter populations demonstrated that individual diet specializations are much more likely to be present in environments of rocky habitat over soft sediment substrates. Daughter Californian otters display the same tool techniques as their mothers, expressing explicit preference for certain methods when eating bivalves or eating crabs.