Project news

Feeding Giants

By Guy Stevens, 15th February 2009

You might think that feeding for a manta ray is a pretty straight forward process; simply find the plankton, unfurl your cephalic fins and open your mouth! But it’s not quite that simple, in fact my research has shed new light on the wide variety of different strategies which manta rays employ to maximise their food intake for effort expended.

Most of my research focuses on the resident manta species which inhabit the reef systems of the Maldives, but every now and then I encounter one of the giant manta species, and sometimes they are feeding. In August I came across the giant manta pictured here feeding in a previously un-documented manor. I’ve seen mantas barrel rolling, feeding in mass groups, scouring the seabed and lining up in chains to feed, but I have never seen a manta feed on its side before!

With black cephalic fins stuck out much further than any resident manta, this individual cruised past me backwards and forwards in this manor for 20 minutes, it was like watching a cross between an X-wing fighter spaceship and a sunfish.

The resident mantas in the area continued to feed in their normal horizontal fashion, with no cross-species interaction at all. So while the two species were feeding on the same food source, they have both evolved different techniques to maximise the amount of planktonic prey they catch. It seems to me that the striking black mouth colouration and angle at which the manta holds its cephalic fins is key to unravelling this fascinating behavioural observation in the giant mantas.

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