Story highlights Scientists flew UAV 100 feet above whales to determine their weight

Two skinny whales died during short scientific mission

Pictures also found pregnant female

Scientists photographed 82 whales during 13-day expedition

(CNN) Killer whale families swimming, playing and, in the sad case of two orcas, dying.

That's what researchers from the federal government's NOAA Fisheries and the Vancouver Aquarium were able document using an unmanned aerial vehicle (sometimes called a drone) flying over the Johnstone Strait off British Columbia earlier this year.

The researchers said it was the first time a UAV, in this case a custom-built hexacopter dubbed Mobly that carried high resolution cameras, to record the behaviors and health of killer whales.

The mission followed British Columbia northern resident killer whales which are considered threatened under the Canadian government's Species at Risk Act, according to a NOAA Fisheries release. The UAV flew at 100 feet above the whales so as not to disturb them and got pictures of 82 whales during the 13-day mission in August.

The researchers were trying to determine the health of the orcas by seeing if they were getting enough food, a task they accomplished by noting whether the creatures were skinny or fat.

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