Friday, July 24, 2009

Whale Shark.

This wonderful giants are the largest of all living fish (it's not a whale). This shark is named so almost entirely based on its size. They can grow up to about 40 ft. and can weigh up to 15 tons (30,000 lbs!) and like elephants, they can live up to 60 - 70 years (reports estimate some might be over 100). Impressive, no?

Around the world, there are different names for them, most based on shapes on its back... in Kenya the story is someone threw shillings on its back, in other places the name literally means 'starts on its back' but my alltime favorite: "Ca Ong"... Vietnamese for "sir fish."

Their life cycle is also interesting. Typically, you hear there are 3 birthing classifications of animals... monotreme (they lay eggs), marsupial (pouch... animals are born premature) and embryonic (matured by mothers nourishment in womb). Whale sharks have something similar to the first and last of these types. They are ovoviviparious... meaning they have eggs, but they remain in the body, are hatched and followed by a live birth. This is different than embryonic because they are nourished through yolk in a closed egg, versus being nourished through tubes connected to the mother. They can give birth to up to 300 pups (yes, shark babies are called pups).

As large as they are, they are known for being gentle. The only injuries they have ever incurred on people are from accidental hits from its tail fin. In fact, they're normally playful with divers.
The other similarity they have to whales is their feeding -- they are a type of filter feeding shark (only 3 species in the world), meaning they eat krill, phytoplankton and occasionally small squid or vertebrates. Apparently when things bigger than that are caught and line the filter, they have been seen to 'cough' as a mechanism to clean the filter. A shark coughing is a funny image. They also swim really slowly... average top speed: 3.1 mph. They have quite a lot of weight to move, so I guess that's fair.

You can find them all over the world in the tropics.... Carribean, India, Africa, Japan, Hawaii, you name it. And they come relatively close to the shore, so if you are a diver, you can see them somewhat often if you are looking specifically for them.

There are a few places you can see them in aquariums... Japan, Taiwan, and the Georgia Aquarium.

Here's a wonderfully relaxing video from Okinawa aquarium in Japan (featuring other fish, too):

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