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| image via Wikimedia Commons |
The earth’s water portion is far larger than the land in terms of geography. Just as land is home to many plants and animals, so are the seas and other bodies of water. Among these fascinating varieties of living creatures live the fascinating gentle giant of the sea.
Ranging from four to fourteen meters long, whale sharks (Rhincodon typus) are the largest members of the cartilaginous fishes (Class Chondrichthynes), making them the world’s largest sharks and fish. Yes, the whale shark is a fish, not a whale as what its name implies. Its closest relatives are the rays and other species of sharks.
The whale shark has and enormous mouth that can reach a width of 1.4 meters, but its not designed to bite off people unlike those of the Great White sharks. Its mouth is at the very front of its head unlike other sharks, which have their have their mouths on the underside of the head. Its wide flat head has a rounded snout, small eyes, five large gill slits, two dorsal fins, and two pectoral fins. Its tail has a top fin that is much larger than the lower fin. Like in most sharks, female whale sharks are larger than the males.
Yellowish markings on very thick dark gray skin best distinguish the whale sharks from other sharks. According to some biologists this skin feature serves as a camouflage for the whale shark when it preys on shoals of fish. The camouflage spots on its skin, especially concentrated on its head, resemble a shoal of fish, thus attracting approaching fishes instead of scaring them away.
Whale sharks sieve enormous amounts of plankton, which they eat through their gills as they swim. Thus, they are called filter feeders. As they swim with their mouths open, masses of water filled with plankton and small fishes enter their mouths and pass through spongy tissues between their large gill arches. After closing their mouths, whale sharks use gill rakes that filter the food from the water. Anything that does not pass through the gills is eaten. Gill rakes are bristly structures in their mouths that trap small organisms, which they then swallow. Despite their enormous size, whale sharks’ diet comprise only of plankton, krill, small fish, squid, and other small invertebrates. This is why they are fondly regarded as the “gentle giants of the sea.”
Whale sharks are solitary creatures. They have been known to inhabit warm waters near the equator both along the coast and in the open seas, from Sabah, Malaysia to the Galapagos Islands. Interestingly, congregations of whale sharks have also been observed to frequent Australia’s Ningaloo Reef, and in Donsol in the Bicol peninsula of the Philippines. However, these regular visits by whale sharks to Donsol waters are no longer a surprise to local villagers, who have been aware of these massive but harmless fish species which they call “butanding.”
Whale sharks are known to spend most of their time near the water surface. This is also one of the reasons why they easily fall prey to unscrupulous fish catchers who hunt and butcher them. Some might say that whale sharks are butchered anyway to provide humans with tons of meat and other raw materials for various commercial products. However, people should consider the decreasing population of whale sharks. In fact, the whale shark is already in the list of endangered species. In the Philippines, it is now illegal to hunt and harvest these “butandings.” Some non-government organizations, like the Haribon Foundation are active with their “save our endangered species” programs to protect the whale sharks as well as other endangered creatures.