Manta rays are highly intelligent and threatened are the biggest rays around the globe.

For a long time, scientists believed there was just one species of manta ray. In 2008, researchers discovered that there are two distinct species which include the reef manta-ray that lives along coastlines in the Indo-Pacific, and the giant oceanic manta ray, which is found in all of the oceans around the globe, and spends the majority of its existence away from the shoreline.
The reef manta ray has an impressive wingspan of around 11 feet in width on average and the huge manta ray from the ocean, which is the largest species of ray — can have a wingspan of up to 29 feet.
Habitat and food
Manta rays of both species are filter feeders: they are able to swim with their mouths wide open, drawing in Zooplankton and Krill as they sift through row after row of micro rakes that line their mouths called Gill plates. They use creative techniques when feeding, often doing repeated somersaults to stay in a single spot that is packed with krill, or chain-feeding–following each other in a circle, mouths open, to create a cyclone effect, trapping food in a spiral.
Giant manta rays live alone or in small groups typically congregating to feed. They’re considered predators and hunt beneath the ocean’s surface.
Intelligence
Mantas rays have the largest brain-to-size ratio of all cold-blooded fish. Research has shown that mantas rays may recognize themselves in the mirror which is a sign of their high cognitive capacity, that is also observed in primates, dolphins, and elephants.
Studies have also revealed that manta rays are able to create mentally-mapped maps of their surroundings by smelling and visual cues, indicating highly developed long-term memory.
Reproduction
Manta rays are believed to live for 50 years.