Thursday, January 24, 2008

Anhinga in Costa Rica - Faking Is Not All Bad


On a trip to Costa Rica last year, we had a most memorable experience in the Tortuguero National Park, watching an Anhinga fishing.


Let me quote you the description of this scene in my book The Cockroach Catcher:

“One of the most exciting birds to watch is the Anhinga. In Costa Rica, they are fairly easy to spot as they dry themselves on a branch or tree stump over the water after their fishing endeavour. The reason it has to dry itself is because it has no oil gland. Some commentators say that the bird is primitive and has not really evolved. Is that so? Without oiling its feathers like most other birds do, it can swim underwater without trapping air and causing a turbulence to slow itself down and to disturb the fish it tries to hunt. Why fix something when it is working well? Unlike the eagle, it does not need to be circulating on top of thermals. To be able to catch fish is more important than anything else.

Its ability to swallow fairly good size fish has been observed and with fish stock not always available, it has the uncanny ability of swallowing a fairly high number of fishes. However, they seem to prefer to kill the fish first. A struggling fish in the stomach may not indeed be the most pleasant thing even for the Anhinga.

There seems little the poor fish can do when faced with such advanced credential in the evolutionary war. That the Anhinga has survived without much evolving is a clear endorsement of its hunting skills. I wonder if its stripy wings mimic shoals of fish under water thus giving the real fish a false sense of comradeship.

In Tortuguero National Park of Costa Rica, we were fortunate enough to observe a catch by the Anhinga. A seven inch fish was the latest victim. The said Anhinga found a little piece of river bank and started to flick the fish. The neck of the Anhinga is strong. I suppose it has to be with all the work-outs under water. The fish seemed exhausted. You could see from the way it looked. Another flick and all was quiet. Cameras clicked and videos zoomed to get a good view.

The fish looked truly dead. In normal circumstances, one flick was enough. It had two. Or was it three?

The bird was now relaxed. Why rush when you can wait till the previous fish is fully down? Spread your wings a bit – there is a huge audience of tourists. It was a beautiful sight – a female Anhinga spreading out its wings. It was indeed a sculpture of exceptional beauty. More cameras clicked and more video whined.

Suddenly. Very suddenly. The little fish came to life. Made a couple of strong wriggly movements, slid into the water and swam off. By the time the Anhinga realised, it was a split second too late. The fish disappeared into the mangrove roots.

We all spontaneously clapped. Support the “under-dog”. Or should it be “under-fish”?

The oldest defence: faking. Not just faking, but faking death.”

Richard Dawkins wrote in his famous book Selfish Gene:

We are survival machines, robot machines, blindly programmed to preserve the selfish molecules known as genes.”

As an illustration, he observed:

“The parent bird limps away from the nest, holding out one wing as though it were broken. The predator, sensing easy prey, is lured away from the nest containing the chicks. Finally the parent bird gives up its pretence and leaps into the air just in time to escape the fox’s jaws.”

In my child psychiatric practice, I came across a number of children who seemed to have made good use of faking. (In The Cockroach Catcher, there are stories of a limping boy, a boy with non-stoppable hiccup, and a 12-year girl who suddenly thought she was only 3 ½.) I have now come to realise that the human brain is often well equipped to protect its owner and wonder about the role of our intervention.

2 comments:

am am zhan said...

This is so interesting. I wish there were shots of the 7 inch fish faking death. Thanks for sharing. am am

Am Ang Zhang said...

Well, it was indeed difficult and partly I do not want to put up a less than perfect pic. the story was unbelievably real. In nature as in human existence we have to make use of all defence mechanisms. I tried to extrapolate what I observed in nature to our daily struggle.