Snake Island:
In case you hadn’t noticed, we get some 120 to 130 visitors to the web site here each month.  Most seem to be passing through, but there seem to be a couple dozen who are sufficiently interested to return regularly.  I don’t know for sure, since of course the statistics package does not give anybody’s address, but it is sort of a feeling I have had for some time.  And it turns out that most of the loyal folks out there are in Brazil. 

So welcome, all you Brazilians.  I have sometimes wondered what I could write about that might be of more interest to you.  So here goes on the Ilha de Queimada Grande.  For the rest of you, that’s an island in the Atlantic measuring about 4,000 feet by 1,000 to 2,000 feet at about 24o 29’ south by 46o 40’ 30” west some 60 miles south of Sao Paulo and 20 miles from shoreline of Brazil. 

And there are snakes.

Here’s a link:

The snakes are a kind of pit viper called a golden lancehead.  The species accounts for most snakebite deaths in Brazil, and these particular snakes are particularly deadly.  They lounge around on the branches of the trees and wait for migratory birds to land.  That means the snake’s venom has to incapacitate the bird before it can fly off for more than a few feet.  Flesh melts.

Not to go on with the creepy stuff, the shocker is that the density of the population is one to five snakes per square yard.  So far as I can make out, the more recent the estimate the lower the estimate.  Maybe they’re dying out. 

They should be dying out.  If you have a cap of, say, 1,000 on your population because of the infertility that comes from low kinship and there are 5 snakes per square yard, then each snake must confine itself to a tiny range.  Effectively it must keep its gene pool confined to 200 square yards and the range of any one snake considerably less than a quarter of that, say 50 square yards or 20 feet across.  One snake should not in its lifetime go more than 10 feet from where it emerged from its egg.  That’s enormously restrictive for a snake that generally measures more than a foot long.  It can’t chase a bird very far.

If you are a regular reader, don’t go there.  The world can’t spare you.  Besides, it’s prohibited.

Many years ago I read an article, “Too Much Easy Living,” that I believe was about the island.  The observation made was that a large proportion of the snakes were infertile hermaphrodites.  Indeed the experts predicted that the proportion of hermaphrodites would increase until the snake population collapsed.  I have looked in vain for that article and cannot promise that I remember correctly.  Still, if it is as I recall, more recent events seem to be vindicating the prediction, and it would be a splendid example of what can happen when a gene pool gets too big. 

I would certainly like to communicate with someone who is an expert on the place, but I would never suggest a person go there.

All the best down there in Brazil.

There have been 125 visitors over the past month.

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