Tuesday, November 29, 2011
Book Review: Dark Banquet
The popularity of leeches for treating a wide range of human ailments almost drove one species of leech (Hirudo medicinalis) into extinction in the 18th and 19th centuries. The demand was so great that more leeches were being harvested than the natural reproduction rate could sustain. Fortunately for the leeches, medical practices changed and leeching stopped being viewed as a cure-all for every ailment. Leeches never totally vanished from medicine and are still being used today, but their application is much more specialized.
Interesting though the leeches were, the best part of the book is probably the section on vampire bats. Vampire bats pose all sorts of challenges for researchers. Among other things, they can be remarkably fastidious -- it's hard to keep some species alive in captivity. There's apparently more involved in bat care than just wandering down to the local slaughterhouse and requesting buckets of fresh blood. You also need a flock of donor chickens that the bats can sample occasionally -- maybe there is something to that staple of vampire fiction, the life source or life energies? Characters in vampire novels are always complaining that, yes, it is possible to survive for awhile on bags of blood pilfered from the Red Cross, but it's not enough -- every so often a vampire needs to get its blood from a real live victim.
One thing that surprised me was learning just how tiny the typical vampire bat is. Seeing a drawing of the preferred position of one species while feeding on chickens roosting in a tree makes it pretty clear that the image perpetuated in horror films -- the huge flapping monstrous bats that look like they could suck an ox dry in record time -- is well removed from reality. Vampire bats are tiny. Of course, if you get dozens of the critters all wanting to feed on just one or two animals, the host animal is going to be in trouble pretty quickly. Farmers in Trinidad lose chickens fairly often to vampire bats -- one bat may not take enough blood for the bird to notice, but multiple bats can cause anemia severe enough to kill a hen quickly.
Illustrations in the book are nicely done and do a great job of complementing the text. As science books go, this one was a joy to read and one I'd highly recommend to anyone who has an interest in biology or the natural world.