The megamouth is a large shark. Fully grown adults are at least 5.5 m in length and 800 kg in weight. They have a very large, broad head, small eyes and five pairs of gill slits. The back is grey to grey/black and the underside is white. The upper surface of the pectoral and pelvic fins has a distinctive, light margin.
The distribution and range of this animal is poorly known. The few specimens found thus far suggest it is found around the world in tropical and temperate waters. Most specimens have been encountered around Japan. The understanding of their habitat requirements is sketchy, but they are thought to spend most of their time in mid water at a depth of at least 100 m.
What is known is that the megamouth is far from common and if the threats to marine life continue it will be enigmatic beasts such as this that disappear first.
• The megamouth shark is the only representative in its family, although some people think it may actually be closely related to the basking shark.
• The megamouth shark, along with the basking shark and whale shark is the only shark species that has forsaken the normal, predatory tendencies of this group for a life of sedate filter feeding. Sprouting from the gills, these sharks have finger like projections, commonly known as gill rakers. These sieve the water for small, marine organisms in a similar way to the baleen plates of the filter feeding whales. In the basking shark, these rakers drop off in the winter, which means they cannot feed. Just where the sharks go at this time of year is another of zoology’s mysteries.
• Only educated guesses have been made of how the megamouth shark reproduces. The ovaries are very similar to other shark species that ovulate large numbers of eggs as food for young developing in the uterus. The females also bear scars, indicative of the nuzzling and biting behavior of copulating males.
• Several megamouth sharks have shown the scars of meetings with the cookie-cutter shark. The megamouth shark may be a favored target of this small, semiparasitic animal. It has a flabby body, which is probably easy to excise lumps from. It swims slowly and it lives in the same places as the cookie-cutter.
Photos credited to www.sharkmans-world.com
