If you have seen a manta anywhere in the world you can contribute directly to the global research and conservation of manta rays by submitting your images and sighting encounters through our sightings upload form. Alternatively you can email us your images directly to IDtheManta@mantatrust.org but please don’t forget to let us know where and when you saw your manta!
Ideally we are looking for images which best show the spots on the underside (ventral surface) of the manta rays. These spots are unique to each and every manta ray, just like a fingerprint they can be used to identify every single individual. Other images which show the top (dorsal surface) of the manta rays, or the tail (ventral) area, can also be used to identify the specific species you encountered and/or the sex of the individual. The more information you provide, the more feedback we can give you on your encounter, so please take a few minutes to send us your sightings.
By cataloguing photo IDs of manta rays, we can develop a better understanding of how large populations are and how the individuals within populations are utilising certain sites in particular areas and where they travel…
With tens of thousands of images entering into the manta database each year, the next step is to match the new images to the existing database and see if we have encountered the pictured mantas before. To do this the Manta Trust, University of Bristol and the not-for-profit company, IDtheAnimal Ltd have come together to produce a piece of software called IDtheManta. Our objective is to create a fully-automated visual biometric photo-ID technology for manta rays which will interface with a global photo-ID database accessible to manta scientists and the general public around the world.
This resource will serve as a massive data source for scientists, enabling research organisations around the world to monitor the migratory patterns of the oceanic manta rays as they roam across the open oceans, and to monitor the smaller scale movement patterns of the more resident reef manta ray populations.
IDtheManta will also help to raise awareness and drive the conservation of manta rays and their habitats globally by providing in-depth feedback to every individual who uploads a sighting encounter to the mainframe database via the Manta Trust website. The mission of the Manta Trust is to use research and awareness campaigning to drive the global conservation of manta rays and their habitat.
How does IDtheManta Work?
Using complex mathematical algorithms, the system automatically locates manta rays within digital images. The computer uses artificial intelligence to learn the features of manta rays so that it becomes better and better at recognising individuals with every new image which is added to the database. Once a positive ID is made, the automated animal recognition technology (ART) generates a biometric-ID from the spot patterns on the manta’s underside. The biometric-ID is then matched against other manta rays in the global database. Where there is a match, the time, date and location are added to the manta’s history file. If there is no match, then a new manta ray history file is created along with its movement data.
If you’d like to know, or do, more check out our Volunteer page and email us to find out how you can teach our database to learn our animals!
Every manta ray has its own pattern of spots on its belly, or ventral surface, take a look at our Seeing Spots section for more information. These spot patterns can be used to identify individual manta rays much in the same way fingerprints can be used to identify humans.
A photograph of the ventral surface is the most important, as it reveals the individual’s identity, and also shows the sex of the animal, which can be used to calculate proportions of males and females in the population. The best photo ID captures the entire underside of the manta, but sometimes manta encounters can be short, so it’s important to photograph the most indicative portion of the animal in a pinch. These areas are different in the two species:
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 oceanic mantas belly. We use this small area below the gill slits and above the tail as the primary ID area for this species.
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. We use the area in between the two rows of gill slits as the primary ID area for this species.
As mentioned above a good ID photo will tell us much more about the manta than just showing us the spot pattern.
Male or Female? How to Sex Manta Rays
Female manta rays tend to be larger and often more ‘friendly’ than their smaller male counterparts. If a large manta is hanging around the cleaning station without much concern for the divers nearby, it’s a good chance that you’re looking at a female, but the only way to be sure is by checking its sexual organs. Just like humans, male and female manta rays have different sexual organs. Female mantas have two pelvic fins that conform to the contour of their body.
Male manta rays also have two pelvic fins, but in addition they have two claspers. Claspers start out as small fins that grow beyond the pelvic fins and become hard and calcified as the male reaches sexual maturity. Looking from either above or below the manta, if you spot two fins extending beyond the main body, you’re looking at a male.
Juvenile mantas can be tricky. Young females look the same as mature females, with nothing but two pelvic fins, but juvenile males are often mistaken for females.
Claspers on young males are small and undeveloped, and when viewed from above they’re not distinctive. Juvenile males can really only be identified from below, where their small claspers can be seen growing underneath the pelvic fins.
Don’t Forget the Top!
Hopefully your manta encounters will last more than a few short minutes. If you have the opportunity to spend more time with a manta, taking photos of the animal’s top, or dorsal side, and profile shots of the manta can also be extremely useful.
The dorsal (topside) patterning of mantas also has key differences between the two species of manta. In the reef mantas (Manta alfredi) all chevron morphed mantas (black topside and white underside) have white patches on their backs.
On reef mantas, these ‘shoulder’ patches form a ‘Y’ pattern just on top of the manta’s head, fading into the black colouration on their backs. In their oceanic counterparts (Manta birostris) dorsal patternings form a ‘T’ pattern and there is a distinctive black/white divide, as opposed to a gradient.
In entirely black mantas this is not as clear but there is still a lot of data to be gained from a good topside picture.
During mating, males bite down on a female’s left pectoral fin in order to manoeuvre; have a look at our Sexual Selection section for more information. This rubs off the skin on the female’s fin and leaves a scar which can show when a female has reached sexual maturity, and how often it has been mating.
By keeping track of pregnant females, we can tell when and how often certain individuals are pregnant, estimate how many babies are being born each year, and track any trends in pregnancies for the population as a whole. If you think you see a pregnant female, make sure you get the profile shot to prove it!