Soaring high above the waves as easily as a bird, mobula rays appear perfectly designed for this astonishing aerobatic display.
Closely related to sharks but with long, flat bodies and wing-like pectoral fins, they are ideally suited to swooping through the water yet seem equally at home in the air, so much so that they have earned the name “flying rays”.
Mobula rays can reach heights of more than two metres (6ft 6ins), remaining airborne for several seconds, but their landings are much less graceful, creating a loud bang as they belly-flop back into the sea.
Sometimes they seem to lose control and do flips and twists
This behaviour – filmed in the Gulf of California, Mexico, as part of a new BBC / Discovery coproduction television series – can last for 24 hours and happens as many hundreds of rays shoal together to form huge aggregations.
“Sitting in a boat in the midst of these aggregations is akin to sitting in a pot of popcorn as the kernels explode into the air. Everywhere you look mobulas are leaping out of the water and landing with a loud smack, sometimes just a couple of meters from you,” says Joshua Stewart, from the Gulf of California Marine Program at Scripps Institution of Oceanography, who studies rays in Mexico and across the world.
“The mobulas launch themselves straight up out of the water at top speed, and most often they land flat on their belly. However, sometimes they seem to lose control and do flips and twists before reconnecting with the water.”
As far as we can tell, all mobulid rays jump
Mobula rays’ elusive nature and skittish behaviour in front of divers has made them difficult to observe in the wild, except when they breach the water. Mr Stewart explains that even large aggregations, like the one in the Gulf of California, can sometimes be hard to find, as they can occur in different locations and at slightly different times of the year.
In order to shed some light on these animals Mr Stewart applies some of his findings from his research into the larger manta rays he completed with the Manta Trust. For example, he knows that manta rays have to start their leaps fairly deeply, in order to build up enough speed to leave the water.
“As far as we can tell, all mobulid rays jump, as do their myliobatid (eagle rays) cousins. Many theories have been suggested [as to why they jump], from feeding, courting, communicating, and ridding themselves of parasites,” he says.