Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Chondrichthyes
Order: Rajiformes
Suborder: Myliobatoidei
Family: Myliobatidae
Subfamily: Mobulinae
Genus: Manta
Species: Manta birostris
Manta rays are easily reconized in the ocean by their large pectoral "wings." Manta birostris have no dorsal or caudal fins. They have two
cephalic lobes that extend from the front of the head and a broad, rectangular, terminal mouth containing small teeth exclusively in the lower
jaw. The gills are located on the underside of the body. Manta rays also have a short, whip-like tail that, unlike many rays, has no sharp barb.
The skin of manta rays is rough and scaly, like that of most sharks.
Size:
Manta ray pups weigh 11 kg at birth and their growth is rapid, with pups virtually doubling
the body width from birth through the first year of life. Manta rays show little dimorphism between the sexes with wingspan in males ranging from
5.2 - 6.1 meters and females ranging from 5.5 - 6.8 meters. The largest ever recorded was 9.1 meters. The average life span of Manta birostris is 18-20 years.
Distribution:
Circumtropical. Manta rays are found in tropical and warm temperate coastal
regions of the world's oceans, generally between 35 degrees north and south latitude, including the coasts of southern Africa, ranging from
southern California to northern Peru, North Carolina to southern Brazil, and the Gulf of Mexico.
Habitat:
Manta Rays, unlike most other rays, are found near the surface of the ocean and to
depths of 120 meters. Atlantic manta rays stay closer to shore in the warmer waters where food sources are more abundant, but occasionally
can be found further from shore.
Reproduction:
Manta Rays are sexually mature at 5 years of age. The mating season of sexually
mature manta rays occurs from early December to late April. Mating takes place in tropical waters (26-29 degrees Celsius), and around rocky
reef areas from 10-20 meters in depth. Manta rays gather in large numbers during this season, where several males will court a single female.
The males swim closely behind the tail of the female at faster than usual speeds (9-12km/h). This courtship will last for about 20-30 minutes
at which point the female decreases her swimming speed and a male will grasp one side of the female's pectoral fin by biting it. He arranges
his body under that of the females. The male will then insert his clasper in the cloaca of the female and insert his sperm, this usually
lasting around 90-120 seconds. The male will then swim away rapidly and the next male will repeat this same process. However, after the second
male the female usually swims away leaving behind the other courting males. The gestation period of Manta birostris is 13 months, after which
females give birth to 1 or 2 live young. Pups are born wrapped up by their pectoral fins, but soon after become free swimmers and fend for
themselves. Manta ray pups are between 1.1 and 1.4 meters when they are born.
Feeding:
Manta rays are filter feeders and primarily planktivores. They often slowly swim in
vertical loops. Some researchers suggest this is done to keep the rays prey within the area while feeding. Their large, gaping mouths and
cephalic lobes unfurled are used to corral planktonic crustaceans and small schooling fish. Manta rays filter water through their gills and
organisms in the water are trapped by a filtering device, which consists of plates in the back of the mouth that are made of pinkish-brown
tissue that span between the support structures of the gills. The teeth of Manta birostris are nonfunctional during feeding.
Behavior:
Manta rays are solitary, free swimmers who are not territorial. Manta birostris
use their flexible pectoral fins to swim gracefully through the ocean. Atlantic manta rays are most active during the mating season, and
have been recorded leaping out of the water to heights of 7 feet, then smacking against the surface. By doing this, mantas may remove
irritating parasites and dead skin on their large bodies. Also, Manta birostris have been seen at "cleaning stations" with wrasse fish
swimming about them picking off parasites and dead skin. Another symbiotic interaction that mantas have is with remora fish, which attach
to the giant mantas and hitch rides with them while feeding on the mantas parasites and on plankton. Manta rays have no particular anti-predator
specializations other than their tough skin, but due to their size they do not have many natural predators.
Distinguishing Characteristics:
This species has a terminal mouth, the head is broad and the
cephalic (head) fins are long. The dorsal coloration is black or reddish brown, and sometimes the black morph has white shoulder patches.
There are reports of albino specimens.
