Leapin’ Lizards!

by Marylou Ferry

Afton Canyon

“I love to teach in the field.” says Professor Marion Preest, professor of biology in the W.M. Keck Science Department. “I really enjoy introducing students to our natural treasures.”

In late April, students hiked along the Mojave River at the only location where it flows above ground, near Afton Canyon. The area is designated as an Area of Critical Environmental Concern to protect plant and wildlife habitat, and to preserve scenic values of the riparian area.

Getting students into the field cements concepts talked about in class. “It’s one thing for me to say that lizards can sprint extremely rapidly or that some lizards will change color to adjust the amount of heat they absorb,” said Preest. “It is quite another experience for students to actually observe those behaviors in the creature’s natural habitat.”

Catching a lizard by using a fishing-pole-style rod with a small noose fashioned from dental floss dangling at the end requires speed and skill. Once the lizards were caught, students were able to engage in key observations.

“Using an infrared camera allowed me to demonstrate how effective sweating is as body temperature regulation,” said Preest. “After examining some reptiles, I pointed the camera at a student’s face. The parts of her face that were sweating the most were noticeably cooler than others.”

The high temperature (107 °) gave the students a sense of some of the challenges desert animals face and an appreciation of the effectiveness of the specializations they’ve evolved. In the classroom, students learn about the evolution, ecology, morphology, and physiology of amphibian species and reptile species. In the field, students observe how these creatures adapted to those stresses to successfully survive (some reptiles for 100 million years and some amphibians even longer).

The creatures’ ability to adapt to stresses such as heat and aridity were pointed out by Preest, including seeking sun or shade, climbing shrubs to take advantage of cooling winds, color change, and changes in orientation to adjust the amount of surface area exposed to the sun.

“Noticing lizards in rocky crevices and under bushes was harder than I anticipated, but we all got better at it as the day went on,” said Alicia Hendrix ’12. “Handling zebra tails and desert iguanas was exciting, and noosing them and taking body heat readings gave me a more solid idea of what being a field herpetologist would actually entail. I feel guilty for saying it, since they weren’t reptile species or amphibian species, but the highlight was definitely the bighorn sheep we spotted on the cliff top near the end of the day!”


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