Not a day late or a dollar short.

It was almost two weeks ago a basking shark washed up on an Aquinnah beach. Somehow, I still feel compelled to go to great depths to find out more about this fascinating creature.

But that might be a mistake. One could miss the basking shark if one delves too deep, because at this time of year these gentle giants swim at or near the surface of the water — basking in the summer warmth and food availability at the top. During the winter, basking sharks are thought to spend time further below the surface, up to 2,700 feet down. 

No matter where they are in the water column, they are not to be feared. The basking shark’s primary food-gathering modus operandi is not to chase and attack, but to float and filter. It glides or swims at two knots per hour, and in that hour more than 2,000 tons of water flow through itsmouth. 

Only a really big mouth could accommodate all of that water. Basking sharks can and do really openwide. Dentists would love this shark, since it can open its mouth up to three feetwide. While that would make an extraction relatively easy, its hundreds of teeth are very small and have relatively littlefunction. A basking shark eats by filtering zooplan kton, small fish and invertebrates out of the water using gill rakes located deep within itsmouth. 

It is no wonder that this shark is also called a big mouth shark. Other aliases include sunfish, bone shark, elephant shark and sail fish. The scientific name of the basking shark is Cetorhinus maximus, a name that is also telling. Ceto comes from the Greek word ‘keto,’ meaning marine monster or whale, and ‘rhinus’ meaning ‘nose.’ The marine monster moniker results from the resemblance of this shark after it decays to a six-legged sea serpent or prehistoric plesiosaur (seamonster). Maximus, of course, describes its standing as the ‘greatest’ fish.

While that last title is debatable, what is not is its designation as the second largest fish, behind only the whale shark. This sizeable animal reaches lengths of up to 30 feet and can weigh upwards of 16tons. 

Big not only describes its size, but also its organs. Consider that the liver of this shark accounts for 25 per cent of its total bodyweight. This large mass helps the shark with buoyancy and energystorage. Of course people have found a use for this gargantuanliver.  Historically, the basking shark was hunted for the oil within, which was used for lampfuel. Up to 600 gallons of oil could be harvested from each baskingshark. And I would be remiss (and cannot resist) to mention the size of the male’s sex organs, called claspers, which can be up to three feet long!

What else is left to say?  With that last comment, both the basking shark and this article are ‘fin’-ished.


Suzan Bellincampi is director of the Felix Neck Wildlife Sanctuary in Edgartown.