Saturday, July 9, 2011

Manta.

This picture is of a small stone ray, a gift from my friend and colleague Andres when he return from  trip to Puerta Vallarta, Mexico. He gave me two of the little rays. This one I keep at home and the other one graces my desk in my office. I love these two little rays - they make me smile whenever I look at them.

When I decided to go to Mexico, I wondered if there were really rays in the waters there and if so what kind. Turns out not only are there rays in Mexico, they have the monster of rays swimming in the waters off the Yucatán Penisula.  Oh yeah. We're talking the giant manta ray!!

The Manta ray (Manta birostris), is a member of the shark family and is the largest of the rays.  These graceful swimmers are up to 9 m (29.5 ft ) wide, but average about 6.7 m (22 ft) wide.  Holy cow!   That's wider than my living room!! The largest weigh about 1350 kg (3,000 lbs).

Mantas are found world-wide in tropical to warm temperate seas.

Mantas are derived from stingrays which explains their flattened body shape. 

Photo by Jesse Cancelmo 
 

Mantas are generally dark brown to black on top vary enormously in color pattern on the shoulders and, especially, the undersurface of the body. It is not known what functions, if any, these differences hold for Mantas. The shape and extent of the shoulder patches, the precise pattern of spots and blotches on the undersurface, and the lifetime pattern of scars form a pattern of markings as unique as a human fingerprint and are used by researchers to distinguish one individual from another.





Mantas feed on plankton, fish larvae and the like, funneling the food into their mouth while they swim, using two large, flap-like cephalic lobes which extend forward from the eyes.
 
Small prey organisms are caught on flat horizontal plates of russet-coloured spongy tissue spanning spaces between the manta’s gill bars.

Since mantas are plankton feeders, some of their ancestral characteristics have degenerated. For example, all that is left of their oral teeth is a small band of vestigial teeth on the lower jaw, almost hidden by the skin. Their dermal denticles are also greatly reduced in number and size but are still present. They have a much thicker body mucus coating than other rays. Their spiracles have become small and non-functional, as all water is taken in through their mouth instead.  Somewhere along the evolutionary timeline, mantas also lost the stinging barb and their pectoral fins developed into graceful, flapping wings.



Mantas frequent reef-side cleaning stations where small fish such as ramoras swim in the manta’s gills and over its skin to feed, in the process cleaning it of parasites and removing dead skin.  Even fish need to keep clean. :-)






Humans are not part of the manta ray diet.  In fact, mantas are extremely curious around humans, and are fond of swimming with scuba divers.  Though I've seen many a photo of a diver hitching a ride on a manta, it's really not a good idea, not because the manta will harm the person but because of the reverse.  If mantas are touched, their mucus membrane is removed, causing lesions and infections on their skin.  We don't want to do harm to these beautiful creatures.

Mantas are known to surface to investigate boats without engines running.  During mating season, they are known to breach the water into the air, leaping out of the water and flapping their fins in an attempt to glide in order to attract a mate.  Apparently, the big air and massive splash-downs are just the thing needed to capture the attention of a lady ray.  Who needs chocolate and flowers? :-)

Check out this video of these graceful sea creatures.  Ignore the fact the woman diving can hold her breath for a freakishly long period of time.  Asthmatically me will have to float on the surface so I won't be doing any *dancing* with a manta ray :-(


I really, really hope we get to see manta rays on our whale shark trip, even if it's just a glimpse from the surface. This is the stuff that I've only ever seen in pictures and on TV. It's rare for someone like me, your typical city dweller, to experience in real life. It's manta ray in Mexico or bust!!