Conservation through Research, Awareness and Education

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Spot the Difference: Patterning & Morphs

This exceptionally spotty male reef manta ray's ventral surface is completely covered in spots and dark shading.

Spots play a crucial role in helping us ‘spot the difference’ between the mantas we see. In both species of manta there are unique patterns of spots on the ventral (underside) surface which we use like fingerprints allowing us to identify every individual manta we see. In the majority of cases mantas have a black dorsal (topside) surface and a white ventral surface, however, in both species there are also a few individuals who are coloured black almost all over…

 

Colour Morphs

Chevron morphed reef manta ray's dorsal patterns vary greatly, from the almost black to some which are ghostly white.

So, before we talk about the spots on a manta lets first have a look at the two colour morphs present in each species. The first morph is the ‘Chevron Morph’, this is characterised by a black dorsal surface which has a white band running across the top of the mantas head. In this morph the ventral surface is white in colour with a varying degree of black spots and shaded patterning spread across the whole area; some mantas have virtually no spots, while other are covered in them.

This chevron morphed oceanic manta ray's dorsal pattern is typical for this species.

The second colour form is the ‘Black Morph’. Mantas exhibiting this colour form are completely black dorsally and almost completely black ventrally, with patches of white often left only around the gill areas. These black mantas look as though a chevron manta has been dipped in black paint upside down; sometimes leaving just the smallest areas un-dipped on their bellies. If you look closely at these black mantas you can actually see the underlying darker black spots which would have been more visible if the individual was a chevron morph.

Black mantas are unbelievably striking, and the black oceanic mantas even more so. Like marine stealth bombers they cruise through the oceans with a sense of grace and calm that never ceases to captivate. The black morph appears to be recessive to the chevron, making up on average just 25-30% of the population where the gene is present. Interestingly, in some populations, like the Maldives Reef Mantas, this ‘black’ gene appears to be completely absent from the population, with every one of the estimated 5,000 reef mantas in the population being a chevron morph.

Black morph oceanic manta rays.

A black morphed reef manta ray.

At the remote islands of Socorro and San Benedicto, 260 miles S-W off the Southern tip of Baja California, a higher percentage of these giant black mantas can be found than anywhere else in the world. This is a very basic overview of these two colour morphs, with a sliding scale of variations to the theme occurring throughout their range and within populations.

 

 

Ventral Spot Patterns

As mentioned above, each manta has a unique pattern of spots on its ventral surface, which remain unchanged throughout their lives. It’s believed that random genetic mutations of the stem cells at the early stages of the pups development result in these widely varying patterns of pigmentation. This means that even if a manta were to give birth to genetically identical twin pups, the ventral patterning of the two would be different.

The unique nature of these spots enables manta scientists to identify every individual manta just by photographing their ventral surfaces. This simple non-invasive technique enables the development of photo-ID databases of all the mantas within the study populations, allowing estimations of population sizes, documentation of movements (seasonally and spatially) and detailed information on the overall demographics and reproductive cycles of the population.

A chevron morphed oceanic manta ray with typical black mouth colouration and the cluster of spots around the abdominal region close to the tail.

As well as using these spots to identify each individual within a population, the distribution of these characteristic ventral spots also varies subtly between the two species of manta rays. A basic knowledge of these subtle differences can therefore enable most people to identify between the two species during underwater encounters in the wild:

A typically patterned chevron morphed reef manta ray with spots and shading distributed across the ventral surface, including between the gill slits.

Oceanic Manta Ray – Manta birostris

On an oceanic manta the ventral surface is almost absent of spots except for a small central cluster which is usually present near the tail on the manta’s belly.  Manta researchers use these markings as the primary ID area for this species.  Oceanic manta rays usually also have dark colouration around and inside their mouth’s and around their gill slits.

Reef Manta Ray – Manta alfredi

On reef mantas, unique spot patterning can be found all over the ventral surface. Some individuals are almost completely covered in spots and in others there is almost a complete absence of spots. Manta researchers use the markings between the gill slits as the primary ID area for this species.

 

 

Help Us Spot The Difference!

  • Taking ID Images: If you happen to be on holiday anywhere where mantas are seen you can take a picture and submit it to our online  IDtheManta database. See our How to Help section for tips on how to take the best photo-ID image.
  • Spotting the Difference: For more information on how to identify between the two species of manta rays, or how to tell the difference between the manta sexes, click here.
  • IDtheManta: In partnership with the University of Bristol & IDtheAnimal (a not-for-profit company) we have developed software exclusively for the identification of manta rays. Click here to see how it works!

© 2017 Manta Trust