Spotlight on Herpetology: How We Collect Snakes and Amphibians Has Not Changed for Centuries, but Once Back at the Lab, Today's Taxonomy Is like CSI
Lathrop, Amy, ROM Magazine
Almost swallowed by darkness, I systematically scan the dense vegetation for signs of life, starting at a tree trunk and moving up the large limbs to the branches high in the canopy. The single beam from my 6-cell Maglite carves through the forest one tree at a time. I have my snake hook at the ready, and my backpack is filled with water, collecting bags, an aquarium net, and containers for collecting tadpoles. I can't forget to train my beam down on the forest floor, where leaf litter, logs, and rocks make good hiding places for my friends.
Fieldwork and museums go hand in hand. The ROM's natural history collections are all about documenting the world's diversity. Very rarely these days do we receive shipments of specimens. To enhance our collections and knowledge of this diverse life, we must go out and meet it face to face.
For herpetologists, fieldwork begins at night. Amphibians and most reptiles are nocturnal, so when the sun goes down we set out in search of these furtive forest dwellers. We also keep an eye out for those lizards and snakes that sleep at night, though they sometimes elude us--the slightest movement of the very pliable tips of branches they sleep on alerts them to danger. Depending on the location, time of year, and weather conditions, our night searches can be action packed--or longgg and quiet, leaving plenty of time to ponder life's important questions.
On really slow nights I often try to think of ways that technology might improve our collecting success--but herpetology is a hands-on discipline. Because reptiles and amphibians are ectothermic (they get their warmth from the environment), we are not able to take advantage of technologies used by mammalogists, such as infrared radiation, which identifies heat-generating objects. With few exceptions, there really are no methods to attract reptiles and amphibians. And although I once caught a very rare gliding gecko in a bat net rigged in the forest canopy, this passive trapping method is not nearly as effective for herpetology as it is for many of the other ologies. Each of our discoveries takes considerable effort. When it comes to collecting, herpetology has not changed since the early 20th century when ROM herpetologist E. B. S. Logier was walking the forests (see "Journal," page 10).
It's the techniques we use to identify specimens that are now very different. Long before Linnaeus came along in the 1700s and introduced the two-word Latin naming system we still use today, taxonomists described species according to their "essences," a metaphysical approach based in Aristotle's writings. Scientists used as few as one or two characteristics to differentiate a species from all others. Sometimes these suppositions were correct, but since the approach does not take into account evolutionary processes, more often than not the conclusions fell short.
Though it was not very scientific, I can appreciate the approach. Sometimes you find a frog or lizard that looks similar to a known species, but when it's in your hand, its head slightly cocked and looking you right in the eyes, something about it strikes you as different. Sometimes putting your finger on this "difference" can be tough. And while scientists have for centuries been using an entire suite of characters to define each unique species, just looking at aspects of an animal's body is sometimes not enough to make a definitive conclusion. That's where the miracle of DNA comes in.
For each animal we sample, we carefully document where in its habitat it was found, and we note the location (with GPS). We photograph each of the specimens, which sometimes number in the hundreds, and take a sample of tissue or blood from each. Some geckos willingly give up their tail for the cause, via an anti-predator defence called caudal autonomy. …