1. We know that there are 11 species in the ray family, counting both manta rays and mobula rays (now among the world’s most threatened fish). Manta rays were only split into two species in 2009, and there's probably a third species residing in the Atlantic.
2. Manta and mobula rays share a fairly similar body structure. Two of their more notable features are the cephalic fins on either side of their head, which are used to funnel plankton-rich water into their mouths while feeding.
These cephalic fins gave them their common name of 'devil rays', though you wouldn't know it from the way they behave.
A reef manta ray shows off its cephalic fins
© Fabrice Jaine
3. The fossil records suggest that 'devil rays' have been around in their modern form for at least 20–25 million years. True manta rays first appeared in the fossil record approximately 4.8 million years ago.
They originally evolved from stingrays, and a 'sting' is still present at the base of the tail in some mobula species.
4. Genetic work by Tom Kashiwagi (Project Manta) and co-authors estimates that the two contemporary manta ray species split approximately 300,000 years ago.
It appears that ancestral reef manta rays may have preferred to remain close to the coasts of these ancient seas, while giant manta rays became more oceanic.
A streamlined reef manta ray © Fabrice Jaine
5. Giant manta rays are found in the Eastern Pacific and embark on significant ocean crossings, whereas reef manta rays stop at Hawaii and French Polynesia.
Giant manta rays reach up to around 7m in width compared to reef mantas, which grow to around 5m in width and can travel 70km in a single day.
6. Manta rays have distinct spots and blotches on their stomachs, which help researchers when trying to count their numbers.
Each manta ray is individually identifiable
© Fabrice Jaine
7. Manta (and mobula) rays have the largest brains of all 32,000 species (approximately) of fish known to date. They display intelligent behaviour, such as coordinated and cooperative feeding.
8. Giant manta rays, in particular, are truly deep-divers. To keep these large brains warm these rays have an amazing counter-current heat exchange system going on within their veins and arteries, which allows them to become effectively warm-blooded, or at least keep their temperature more stable than most fish.
Group feeding in reef manta rays
© Fabrice Jaine
9. Manta rays are very vulnerable to overfishing. They produce only one large baby on average every one to three years. They also grow slowly and have a long lifespan, some wild manta rays have been seen over 30-year-periods.
10. The global catch of manta and mobula rays has dramatically increased over the last decade due to demand for their gill rakers from China, where they are sold as medicinal products.