Killer whales caught on video grooming each other with seaweed after master's student noticed "something kind of weird" going on

Killer whales have been caught on video breaking off pieces of seaweed to rub and groom each other, scientists announced Monday, in what they said is the first evidence of marine mammals making their own tools.

Humans are far from being the only member of the animal kingdom that has mastered using tools. Chimpanzees fashion sticks to fish for termites, crows create hooked twigs to catch grubs and elephants swat flies with branches.

Tool use in the world's difficult-to-study oceans is rarer, however sea otters are known to smash open shellfish with rocks, while octopuses can make mobile homes out of coconut shells.