Note:
Giant Manta Rays are commonly referred to as the Atlantic manta ray.
However some specialists recognize two other species of manta, known
as the "lesser" devil rays, Manta hamiltoni (Pacific manta
ray) and Manta alfredi (Prince Alfred's manta ray).
Geographic range: M. birostris
can be found between 35 degrees north and south latitude in coastal
regions of Atlantic, Pacific and Indian oceans. In Mexico it can be
found along both coasts.
Physical characteristics: The most
prominent feature of giant mantas are their large, wing like, pectoral
fins and front lobes extending on both sides of the large mouth opening.
There are no dorsal or caudal fins. Mouth is large, rectangular and
in terminal position. Teeth, which are small, can be found only in
the lower jaw. Gills are present on the underbody. Tail is whip like
and has no barb.
When newborn, mantas weigh about 10 kg, but can reach up to 1200 -
1400 kg when adults. The largest individuals span over 6m between
the tips of the pectoral fins. There is no sexual dimorphism, but
females tend to be a little larger than males. The entire skeleton
is cartilage, just like in sharks. Skin is rough. Overall upper body
color is dark brown to grayish black, underbody is whitish.
Food habits: Planctivorous surface
filter feeder. The large, gaping mouths and cephalic lobes are used
to herd plankton crustaceans and small schooling fish. The teeth of
Manta birostris are nonfunctional during feeding.
Mantas feed often at the water surface in slow and long sweeping circles.
Reproduction: Sexual maturity is
reached at 5 years of age. Mating occurs seasonally around rocky reef
areas from 10-20 meters in depth. 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 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. The pups are between 1.1 and 1.4 meters big when they
are born.
Behavior: Solitary, non territorial.
A tendency to visit certain areas was observed. These are called "cleaning
stations" with wrasse fish swimming about them picking off parasites
and dead skin. Atlantic manta rays have no special anti-predator defense
system other than their tough skin, but due to their size they do
not have many natural predators. Large sharks have been known to attack
Atlantic manta rays.
Habitat: Surface ocean waters to max. depths of 120 meters
(photic zone), prefer in -shore, warmer waters where food sources
are more abundant, but occasionally can be found further from shore.
Biomes: reef, temperate coastal,
tropical coastal |
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