Devil rays dive deeper, faster than most other ocean-dwelling animals

BBC : Devil rays had been thought to be a tropical fish because they dwell in relatively warm surface waters. So the presence in the animals’ skull of a mesh of large and small arteries, called the rete mirabile , had puzzled researchers for some 30 years. The rete mirabile help keep the brains of cold-water-dwelling fish warm and functioning. Recently, Simon Thorrold of the Woods Hole Oceanographic Institution and colleagues tagged and tracked 15 Chilean devil rays (Mobula tarapacana) in the North Atlantic Ocean over several months. They were surprised to find that the rays could dive at speeds up to 22 km/h to depths of almost 2 km—faster and deeper than most other sea-dwelling creatures, including sharks and whales. In between dives, the rays floated near the surface, presumably to warm themselves back up. The fish could provide an important link between surface ecosystems and those of the deep ocean.