SCIENCE WHALE'S SCHEME : SOCIAL COOPERATION

Want to get on a killer whale's good side ? Kelp might help : A hundred feet or more above the Salish Sea - high enough to avoid spooking any marine mammals below - a drone camera recorded orcas periodically pairing up to perform a sort of swimming, rolling hug.

That was nothing new for the Southern Residents, a group of orcas in the Pacific Northwest that lives south of other groups.

But when researchers inspected the drone videos, which were recorded last year, they noticed that a little piece of kelp was often  sandwiched between the creature's bodies.

The research, published in the journal. Current Biology, is among the most compelling evidence yet that marine mammals make and use tools.

Michael Weiss, an author of the study who is the research director for the Center for Whale Research in Washington State, said the Southern Residents had long used their intelligence and social skills to adapt to a challenging environment.

The group of 73 orcas, often called killer whales, was listed as endangered in 2005.

The Publishing continues to Part [2]. The World Students Society thanks Jacey Fortin.