Diving with Mobular Rays

Giant Oceanic Manta Ray

(Manta birostris)

Mantas are the largest of the Ray Family, reaching up to 8m from wing tip to wing tip! If we are lucky the Manta Birostris or Giant Manta, can be seen out on Hin Daeng and Hin Muang.

Rays along with Sharks are an Elasmobranch and have skeletons made up entirely of cartilage. The genus Manta is part of the Eagle Ray family, where it is grouped with Mobula Rays (Devil Rays) in the subfamily Mobulinae.

Manta birostris @ Hin Muang

There are two distinct species of Manta: the smaller Manta Alfredi, has a white or pale coloured mouth and tends to be resident in coastal areas. Manta Birostris, which is larger and has a much darker coloured mouth, these migrate across open oceans visiting reef mounts and pinnacles for cleaning, parasite removal and feeding.

Mantas have large pectoral fins, which give them a blanket-like appearance, hence their name Manta meaning "cloak" in Spanish. These large pectoral fins are able to propel them through the water, gracefully gliding and even making acrobatic movements.

Giant Oceanic Manta Ray @ Hin Daeng

Diver with Giant Oceanic Manta Rays @ Hin Muang

Mantas are filter feeders and sieve their tiny food from the water. Most Rays have a mouth on the underside of their head, while the Manta have theirs at the front. While feeding, they use a pair of fleshy flaps on each side of its head called the Cephalic fin, to channel plankton into their mouths. These fins are rolled into spirals while not in use. Gill Rakers, finger like projections on the gill arches, strain and capture food. Like most Elasmobranch, they must keep swimming to allow oxygenated water to pass through their five pairs of gill slits.

Like Sharks, the Manta fertilises their eggs internally and gives birth to live young, called pups. The manta has one, sometimes two pups per pregnancy and are independent from birth. They will remain in shallow water for a about a year, before heading further offshore and beginning their migration cycle.