Whether you have been diving with manta rays in the past, or if you’re looking forward to your first dive with these incredible creatures, you are certain to long for that next manta ray encounter with excited anticipation. Graceful and mysterious, manta rays captivate the imagination whenever they are seen. Just what makes mantas so special? Let’s take a look into their lives.
Manta Rays: The Basics
Often seen feeding in small groups, and sometimes in pairs or alone, manta rays are often seen in places like Thailand, Indonesia, Myanmar, and Fiji. They are also seen in the Philippines, Australia and Southern California, the Solomon Islands, and in many other areas – their population is distributed around the globe, usually between 35 degrees north and 35 degrees south latitudes. While they are capable of crossing vast expanses of open water, they are often encountered along coral reefs and in rocky areas where plankton is abundant. Although they do make deep dives to about 500 meters, mantas are usually encountered in much shallower water.
Part of the Myliobatidae family and the subfamily Mobulinae, Manta Birostris are capable of growing to massive sizes; the largest specimen ever found had a wingspan of 25 feet and weighed 2,900 pounds. Extremely intelligent, with the largest brain to body ratio of any related sharks, rays, or skates, they are sometimes called Devil Rays or Devilfish; and while different manta populations exhibit a variety of physical features, there is only one species. All manta rays share the same basic mitochondrial DNA structure.
While manta rays are usually solid black to solid white on their ventral sides, their dorsal surfaces are varied in both color and pattern; researchers diving with the same mantas are able to identify individuals with ease. Some are nearly black, while others are brownish red; many have white or light colored patches or patterns, as well.
Cephalic lobes, which are extensions of their pectoral fins protrude forward from mantas’ heads, creating a funnel that brings plankton and other tiny creatures into their broad, cavernous mouths. It is the terminal position of the manta ray’s mouth that allows for easy identification; mobula rays, which are similar to mantas in appearance, have their mouths positioned below their heads instead of in front. Although mantas have as many as 300 rows of tiny pinhead sized teeth on their lower jaws, they are filter feeders, consuming as much as twenty to thirty kilograms of plankton each day.
Manta rays court like many other marine species do, with males pursuing females before mating. This often happens near the full moon, and a train of males will normally follow a female before a single male manages to mate successfully. After approximately 12 months, females give live birth to their young; usually two pups at a time, in shallow water. Baby manta rays stay in the shallows for several years before moving away toward deeper offshore waters. When they are first born, the pups weigh approximately 25 pounds apiece. Female mantas normally give birth every two years, taking a year off between pups to allow their bodies to recover. Manta rays can live for an estimated 20-25 years.
Diving With Manta Rays
Despite their sometimes enormous size, mantas do not bite, nor do they attack humans or other creatures. This was only discovered after a series of movies in the 1930’s and 1940’s had depicted mantas as frightening sea creatures capable of great destruction. Today, their gentle nature as well as their massive size and friendly personalities have made them a favorite with divers everywhere.
In many areas, manta rays seem to look forward to interacting with human visitors, and so long as they are not frightened, they may even approach divers. In areas where divers are allowed to pursue them, they often choose to keep their distance, and a manta ray that has been harassed will not usually return to the area where a negative encounter took place.
In order to enjoy diving with mantas, it is best to enter the water as quietly as possible, make your way to a position where you can relax and hold still, and simply watch the giant rays as they go about their daily routines. Often, they will approach divers, sometimes playing in our bubbles, and sometimes even brushing up against us. No matter how close the mantas come to you though, never reach out and touch them, since their skin has a gel-like protective coating that can be removed by touch, opening the manta to bacterial infection. In addition, never grab a manta ray or try to hitch a ride.
Many manta rays seek direct eye contact, which is something few other marine animals seem to like. In addition, they do not mind being photographed, although they are sometimes startled by flashes. A startled manta will roll onto its back, make a deep dive, or swim away; only slowing once it has created distance between divers or predators and itself.
While only very large warm-water sharks, such as tiger sharks and bull sharks are known to prey on manta rays, they are often harvested for their meat, and for their brachial gill plates, which are used in traditional Chinese medicine. In Indonesia and the Philippines, fishermen take hundreds of manta rays each month, capturing them, along with dolphins and endangered turtles, in massive drift nets up to a kilometer long. In some places, people hunt them for their skins, which they then make into items like wallets and handbags.
Even though they are found in all tropical oceans, manta rays are at risk; not only due to being overfished, but because of their low birth rates and global pollution. Luckily, even countries where manta ray fishing is allowed, they have begun to recognize that healthy manta populations play an important role in driving eco-tourism and attracting divers. Important ecological reserves and protected marine areas offer shelter to mantas and other at-risk marine life, and overall, conservation efforts are improving. The species is listed as vulnerable on the International Union for Conservation of Nature’s conservation status list; with effort, these beautiful animals can be pulled back from the brink.