Which animals besides primates use tools?

The answer

Tool use is far more widespread in nature than once believed. Sea otters float on their backs and use rocks as anvils to crack open shellfish, often keeping a favorite stone in a pouch of loose skin under their arm. Bottlenose dolphins in Shark Bay, Australia, wear marine sponges on their snouts to protect them while foraging on the seafloor, a behavior passed culturally from mother to daughter. Alligators and crocodiles have been observed balancing sticks on their snouts near egret nesting colonies, luring stick-gathering birds within striking range. Egyptian vultures throw rocks to break open ostrich eggs. Archerfish shoot precisely aimed jets of water to knock insects off overhanging vegetation. Even some insects use tools: the assassin bug stacks dead ant carcasses on its back as camouflage and bait.