Image courtesy of Whooping Crane Eastern Partnership
In a week in which the animal news was all about some jerk(s) shooting endangered Whooping Cranes in Alabama, Georgia and Indiana, it is great to hear about their reintroduction in Louisiana.
The species went through a genetic bottleneck of decidedly non-biblical proportions in 1938, when only 14 adults were alive on the planet. Travis Glenn, Wolfgang Stephan and Michael Braunt of the University of Maryland and the Smithsonian Institution demonstrated in a 1999 study that only one-third of the species' genetic variation remains in the approximately 150 birds living today.
To get your mind around that, imagine that all of the nearly seven billion humans on the planet - except for 14 random individuals - suddenly died. What would the survivors look like? Who knows - they were just lucky enough to be in the right place at the right time. Do you think those 14 humans would contain amongst them all the genetic variation of our species?
Not even close. We have two sets of 23 chromosomes, which means that an absolute maximum of 46 different versions of every gene could be conserved. And that is only in the extremely unlikely event that every single one of the 14 survivors was carrying two different and unique versions of every gene in the genome.
The bad news for Whooping Cranes is that even when boneheaded people aren't shooting them they have a hard time staying one step ahead of extinction. They have small populations (see above problems with small populations and genetic diversity), they produce small broods of two eggs and rarely raise more than one of them (a curious habit I will be writing about in the future), and do not even start mating until several years after reaching sexual maturity.
So good luck to the Whooping Cranes re-introduced to Louisiana this month after sixty years. I am quite afraid you are going to need it.
And to the people of Louisiana: For Pete's sakes, don't shoot them!
(A note to my readers: Please leave a comment on this or any other post on The Birds and the Bees! I would love to hear what you think about idiots who shoot endangered species, whether or not the government should be spending so much money trying to save them (the cranes, not the idiots), or just what you think about idiots who write blogs about spider sex and related topics...)
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