Rescuers are trying to save at least 16 pilot whales that stranded themselves in very shallow water in the lower Florida Keys Thursday afternoon, reports 7News, a local news station and website in Florida.

By Friday morning, the rescuers had carried six pilot whales into a lagoon, where they are being monitored, according to 7News.

Pilot whales form close bonds with one another, so it's not uncommon that they'd beach themselves as a group, say, if one individual were ill, the news report adds. In fact, a mother and calf had gotten separated so they couldn't see each other, said rescuers, who then maneuvered the calf so it could see its mother.

Two of the stranded whales have already died, according to the news report, which noted that the last mass stranding of this size occurred in April 2003, when 28 pilot whales stranded themselves in the shallow waters northwest of Big Pine Key.