Herps in the News: City Lizards

Hi everyone! I found a really interesting article discussing how a species of anole (Anolis cristatellus) is able to withstand hotter temperatures in urban environments. Anolis cristatellus is a species of lizard that lives in Puerto Rico. Many of them can be found in forest environments, but some have made their way into the city where temperatures are warmer because of the concrete building structures, pavement, etc. In the article biologist Kristin Winchell notes, “We have found that they are able to maintain their function at temperatures of about 0.82 degrees C (or 1.47 F) higher on average across all populations.” By this Winchell is stating that these anoles living in urban environments have the ability to continue doing normal functions such as catching prey even at very high temperatures around 104 degrees F. 

As we have learned in our Herpetology course, cold-blooded animals rely on behavioral thermoregulation to maintain stable body temperatures. This can cause the animal to be environmentally constrained. Interestingly, anolis cristatellus is less environmentally constrained due to its ability to withstand very high temperatures. This allows the species to be able to function for longer periods during the day as well as even being able to rest it’s body on hot surfaces. 

Anolis cristatellus

          This article discusses how a group of scientists studied the differences between forest anoles and city anoles located in Puerto Rico. The evidence concluded that there is one specific gene that was different among the two groups of lizards and this gene is linked to thermal tolerance. This evidence suggests natural selection is occurring in that lizards living in urban environments have a gene that allows them to be able to survive such hot temperatures. 

Link to article:

Hot time in the city: Urban Lizards evolve heat tolerance 

https://www.sciencedaily.com/releases/2020/03/200310094231.htm