Thursday, December 2, 2010

Younger White Sharks, Weak Jawed or Weak Willed?

The Nano Patents and Innovation Blog (yup, it exists) has an interesting look at sub adult white shark predation and the current thought about "one bite predation" in this group.

It's been long known that most white shark attacks on humans are "one bite affairs" that rarely lead to death, unless the target is unfortunate enough to have an artery severed.

Today's post in the NPI suggests that sub adult white sharks lack the actual jaw strength to complete a successful predation hence the one bite attacks.

Interesting stuff.

I have seen enough "repeated attacks" on the target prey species of sub adult white sharks to offer another analysis.

Weak Jawed or Weak Willed?

It would seem to me with millions of years of evolution behind them, white sharks go though a guided predatory evolution as they transition between sub adult and adult phases. It's a learning curve that is reward based. If the bite is successful, i.e something in the bite process fires off the evolutionary neurons in the sharks brain that says "aha, food" the attack continues. We see this with tuna and white sharks world wide. Even deeply frozen tuna that is as hard as granite.

If, on the other hand, the attack hits a surf board, or beer can, or floating seagull, those same neurons come into play and the attack becomes a "one bite affair".

Dr. Peter Klimley at California's U.C Davis spent years at the Farallone islands in the 80's testing this same hypothesis. Reward based predation.

While my analysis is based on years of face to face observations with white sharks using baits and decoys, I would lean towards an evolutionary process that guides the "one bite" sub adult conversation. Jaw strength might have something to do with it, but is it the driver?

As anyone who has been fortunate enough to watch sub adult white sharks savage an 80lb frozen tuna carcass will tell you, once the evolutionary tumblers in a white sharks brain have fallen into place, these magnificent predators are not to be deterred and weak jaw or not, they are in it to finish it.

Cheers,

Patric Douglas CEO
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Shark Trust Magazine 2010

The Shark Trust is happy to announce that the 39th issue of Shark Focus will shortly be making its way to our members.

The Shark Trust magazine is issued three times a year and contains all of the latest news in shark conservation and research. You can also find out what the Shark Trust has been up to over the past couple of months and keep informed about our latest campaigns.

Shark Focus is the perfect read for shark enthusiasts of all ages; this November issue is brimming with a range of interesting articles written by experts in the field and accompanied by some stunning photography.

In this edition, the
Scubasigns Foundation and the Maldives Whale Shark Research Programme provide us with an insight into the remarkable relationship that fishermen in Indonesia share with an aggregation of Whale Sharks. We investigate why some species of shark enter into a natural state of paralysis, known as tonic immobility, learn why the Hammerhead Shark has such a bizarre shaped head and discover more about sexual segregation in Chimaera.

The fifth series of Shark HardTalk features interviews with George Burgess (from the International Shark Attack File), eco-tourism operators Chris Fallows, Mark Addison and Craig Ferreira and Shark Trust member, Danny Aslan, as Chairman Richard Peirce debates the pros and cons of the baiting, chumming and feeding of sharks.

Shark Focus 39 is guaranteed to be an exciting read!

To become a Shark Trust member and receive your free copy of Shark Focus please, click here