Mobula Ray: The Jumping Bean Of The Sea

On May 26, 2014 by Tim Newman

Meet The Mobula Ray

Mobula ray (Mobula mobular), also known as flying ray, devil fish and my favourite – giant devilray, are huge epipelagic batoids. Basically underwater bats. They aren’t well understood and are relatively unstudied. It’s difficult to get an idea of the mobula ray’s size from the pictures, but to give you an idea, their wing span can reach over 5 metres and they can weigh as much as a tonne. The mobula ray are pretty similar to manta ray but slightly smaller and much more prone to leaping from the water; they’ve been recorded getting up to two metres of air on a good day.

Why Are They Endangered?

Mobula ray are considered endangered and are often caught up in fishing nets accidentally. These plankton eating bats of the sea have a long gestation period and only produce one pup at a time, this makes them all the more susceptible. Although from the clip at the bottom you’ll find it difficult to believe they’re endangered.

Another factor weighing the mobula ray down is that Chinese medicine uses their branchial filaments or ‘gill rakers’ (below). This gives an incentive to the fishermen of Southeast Asia and East Africa to search these ray out. It goes without saying, but there is no scientific evidence that these parts help with any ailments at all.

“Mobula breaching” by Nick Bonzey from Corvallis, OR – Bat Rays catching some air. Licensed under CC BY-SA 2.0 via Wikimedia Commons.

Interestingly and rather sinisterly, there doesn’t seem to be any mention of gill rakers from rays in any old traditional Chinese medicine books. It appears that some marketing wizard has found a way to sell on bits of fish which are regularly caught by mistake and not valued for their meat. Because the rays use these grills to filter water for food, the marketing spin is that in powdered form the gill rakers can help filter your blood… I mean… people, please… just listen to how stupid that sounds.

What’s With The Jumping?

So why do they jump? Nobody knows for sure. It’s possible that it helps shift parasites out of the mucus layer on their skin, maybe it’s a form of communication or showing off to the ladies. Or, as I like to believe – it’s just for fun. Rays are pretty intelligent when compared to other species within their fishy cohort. Divers have described them interacting in relatively thoughtful ways. So maybe they are just enjoying themselves?

The following video of mobula ray has had millions of views so you may be familiar with it, but it’s well worth a second watch. It’s shot off the coast of Baja, California and shows a humongous troop of mobula rays just hanging out. No one knows exactly what they’re doing in such a huge group, but they look like they’re having a good time.