The warm sunny days of early spring make me feel like a lizard. I just want to lie on a rock, bask in the sun and thaw out my bones. The (mostly) warm sunny weather that we have enjoyed the last couple of weeks brought out the lizards in the Grand Valley. Many of us are familiar with the iconic collared lizard, which graces Colorado National Monument t-shirts. It is probably one of the most spectacular lizards in North America, and a friend of mine dubbed it “the Vegas showgirl of lizards.” With their bright yellow heads, speckled blue bodies and striking black neck bands, collared lizards are pretty razzle-dazzle. Even their behavior is showy- they often perch on prominent sunny rocks as if posing for the paparazzi and have been known to run on their hind legs.
While the collared lizard attracts a lot of attention, the other lizards in our area often go unnoticed, or barely acknowledged as a small dark shape scurrying under a rock as we hike past. At least nine species of lizards live in the Grand Valley, and are most often seen in the red rocks of the Colorado National Monument or McInnis Canyons National Conservation Area. And while none are quite as eye-catching as the Collared Lizard, they are worth a second look. The most interesting, to my mind, is the plateau striped whiptail (Aspidoscelis velox). If the collared lizard is the Vegas showgirl of lizards, the plateau striped whiptail is the Amazon.
In Greek mythology, the Amazons were a race of women warriors who isolated themselves from men, except for an annual visit to a neighboring tribe for the purposes of reproduction. Any male babies that resulted were killed, abandoned or given to a neighboring tribe- only females were allowed to remain in Amazon territory. Plateau striped whiptails take this “no boys allowed” policy to an even greater extreme- there are no male plateau striped whiptails at all. The entire species is female and they don’t even need males to reproduce. These lizards reproduce asexually, via parthenogenesis, a process in which an egg cell starts dividing and produces an embryo without being fertilized by a sperm. Because there is no contribution of genetic material from a male, the offspring is genetically identical to the mother and therefore a clone. Parthenogenesis is actually very common among the different species of whiptail lizards- the Colorado checkered whiptail, which occurs in southeast Colorado is also parthenogenic. Scientists believe that these parthenogenic whiptail species arose when two typical sexual species hybridized.
As bizarre as it may seem, parthenogenesis is not as rare as you might think. It is actually very common in plants. All ants, bees and wasps use parthenogenesis to produce male offspring. It has also been known to occur occasionally in sharks, turkeys and chickens, though usually the embryos that result are usually not viable.
Some of you may remember the excitement (and some anxiety) in 1996 when scientist cloned a sheep. The animal, which they named Dolly, even made the cover of Time magazine with the headline “Will There Ever Be Another You?” Many people think clones were creepy and they are a major theme in science fiction novels and movies like “The Stepford Wives,” “Blade Runner” and “Gattaca.” But for those of us here in the Grand Valley, we needn’t turn to novels or films to find clones- a casual hike up a local canyon might grant us an encounter with a clone in the flesh. In the case of the Plateau Striped Whiptail, or “Amazon” lizard, reality is stranger than fiction or, in this case, Greek mythology.
This article was originally published, in an edited form, on Wednesday April 24 in the Grand Junction Daily Sentinel. You can read it in the Sentinel here.