Friday, October 7, 2011

Parasite Rex

Inside the Bizarre World of Nature's Most Dangerous Creatures

It's a disturbing fact that the body of any creature, including our own, is potential habitat. We are a house and the mice want in. Or as the prologue puts it: "a vein is a river."

The life cycle of a parasite can be ingenious, complex, and gruesome, and the book provides some startling examples. Among the 16 pages of b&w photos you'll find one of a crustacean that has devoured the tongue of a fish and taken its place. But what makes this book remarkable is that it goes beyond such sensational examples and addresses broader issues.

Parasites, it seems, have been practising their trade since the dawn of life, and any ecosystem without them is likely to be unhealthy. Parasites may even have been responsible for the development of sex and language.

Then there are social parasites, like the cuckoo. Ultimately we ourselves may be seen as parasites -- with the planet our host.

Behaviour Modification

One of the truly shocking aspects of parasitism is the ability of some organisms to alter the behaviour of their host. Toxoplasma causes rats to be less wary of cats, the parasite’s final host.

Ants that have ingested lancet flukes leave their sisters and spend the night at the top of a blade of grass, the better to be consumed by a grazing mammal.

Sacculina, a parasitic barnacle, penetrates a crab’s leg joint, sends out "roots" through the crab’s entire body, and emerges as a sac on its ventral surface. The crab loses its ability to reproduce, becoming "genetically speaking, a zombie: one of the undead serving a master."

...parasites such as Sacculina...control their hosts, becoming in effect their new brain, and turning them into new creatures. It is as if the host itself is simply a puppet, and the parasite is the hand inside.

Makes one think of Heinlein’s Puppet Masters, and the movie Alien, doesn’t it? The author mentions them too.

Carl Zimmer

I enjoyed Parasite Rex so much that I immediately went out and bought two more of Zimmer’s books. Check out his website, which contains numerous articles he has written, as well as Chapter 1 from this book.

You can also find a link to his blog on Discover’s website, and there a link to a a photo gallery of scientific tattoos, the basis for a cool book coming out this fall called Science Ink.

Zimmer has had a tapeworm named after him.

A Few More Quotes

It’s time to put the parasite alongside the lion.

Castration is a strategy that any number of parasites have hit on independently...

Parasites have been a dominant force, perhaps the dominant force, in the evolution of life.

There are more human intestinal worms than humans.