Study shows that devil rays dive deep

Deep diving mobulas on Wetpixel

Dr Simon Thorrold, an ocean ecologist at the Woods Hole Oceanographic Institute and a team have published a paper in the journal Nature Communications showing the results from tagging 15 Chilean devil rays (Mobula tarapacana) with special satellite tags.

The tags not only record the animal’s position, but also depth, light and temperature. Position information showed that the rays were travelling up to 3,800km(2,360 miles) from the Azores where they were tagged, but perhaps more interestingly, the team also discovered that the rays are diving to depths of up to 1,848m (6,063 ft) during dives lasting 60-90 minutes. In addition, the animals were descending at rates of up 22km/h (13mph), much faster than whales or dolphins.

Mobula rays have a mesh of arteries called a rete miracle cranica in the front of their skulls. Up until now, its purpose has been unknown, but it has been hypothesised that it serves to keep the brain warm during these extreme deep dives.

(Image from Shutterstock)