Since last year, scientists have noticed something disturbing: polar bears are catching and eating white-beaked dolphins that have ventured too far north. While polar bears eating cute aquatic mammals is nothing new, the fact that the two species have crossed path raises some red flags. 

The first observation of this encounter happened in April 2014. Jon Aars of the Norwegian Polar Institute was collecting data in Svalbard, Norway when he stumbled upon a bear with two dolphin carcasses. Aars and his colleagues had never seen this sort of encounter before. 

"We were surprised as dolphins have not been reported in that area before," Aars told NewScientist

The polar bear likely caught these rogue dolphins similar to how it catches seals: Dolphins periodically surface in holes in the ice in order to breathe, which means a patient bear could sit and wait for the right moment to snatch its prey. After getting its fill, the frugal bear stores the rest of its kill in the ice for later. 

Since this first sighting, at least five more bears have added dolphin to their menus. This disturbing trend is likely the result of global warming. Scientists believe the dolphins ventured north earlier than usual due to unseasonably warm weather, and were then blown off-course and stuck in polar bear country. 

As a group of scientists explained in Polar Research"We suggest they were trapped in the ice after strong northerly winds the days before, and possibly killed when forced to surface for air at a small opening in the ice."