Central American brown basilisks (Basiliscus vittatus) are among the members of a lizard community that converged on a lower temperature tolerance after a cold snap in Miami.

Some lizard species in the USAs tropical city of Miami, Florida, which previously could not withstand extremely cold weather, now seem to have shockingly developed tolerance against it, new research has found.

January 21, 2020, marked one of the coldest nights in south Florida. The temperatures dropped so low, that the lizards that were napping on the trees ended up getting stunned, lost their balance, and fell off on the streets.

Researchers utilised this opportunity to collect the scaled survivors of this cold night, as it provided them with a unique chance to understand how lizards are affected by extreme climate events. Post collection and examination of the lizards, however, the researchers were stunned tooand not by the cold this time around.

The researchers found that all the lizards they collected off the Miami streets could survive temperatures as cold as 42 degrees Fahrenheit (5.5C). This was a lot lower than their previous tolerance levels which biologist James Stroud and his team, from previous research, knew to be between 46 to 52 degrees Fahrenheit (7.7 to 11.1C).

"Prior to this, and for a different study, we had measured the lowest temperatures that six lizard species in south Florida could tolerate. We realised after the 2020 cold event that these data were now extremely valuablewe had the opportunity to re-measure the same lizard populations to observe if their physiological limits had changed; in other words, could these species now tolerate lower temperatures?" Stroud added.

Before the event of the cold night, the temperature tolerance of the lizards varied. For example, large lizards like brown basilisk showed low tolerance to low temperatures, whereas other species like the Puerto Rican crested anole were comparatively more tolerant. But after the event, it was seen that all the lizard species were capable of tolerating the same levels of low temperature.

This was a surprising and unexpected outcome, as the species differ in body size, physiology, and ecology, and yet have the same level of cold tolerance. Therefore, these research findings acted as proof that tropical, cold-blooded animals whose primary characteristic is their inability to withstand rapid changes in climatic conditions, can sometimes withstand extreme climatic conditions that go beyond their established physiological limitations.

The shift towards tolerating such low temperatures is very significant. However, the researchers were unsure if the reason behind this was indeed natural selectiona process that results in the adaptation of an organism to its environment by means of selectively reproducing changes in its genetic constitution. The rapid evolution of this tolerance among the lizards has raised several questions.

Jonathan Losos, director of the Living Earth Collaborative at Washington University, described these tropical lizards ability to withstand near-freezing temperatures as very surprising, while also adding that our future goal should be to understand how this tolerance was achieved.

One perspective is that the lizards that could not tolerate the cold weather simply died, while the ones which had the tolerance survived. This can be attributed to the natural selection of species. On the other hand, it could also be an example of physiological adaptation, known as acclimation, in which case the physiology of lizards may have changed when exposed to lower temperatures, which effectively developed their tolerance.

"It is widely thought that tropical and subtropical species are going to be especially vulnerable to changes in temperatureparticularly extreme spikes of heat or coldas tropical areas do not typically have strong seasons," Stroud said. Temperate creatures, on the other hand, are well adapted to both summer and winter extremes.

But now, these new findings are bound to play an important role in helping us better understand the effects of climate change on tropical and subtropical species. While there is no question that climate change is a huge threat to ecosystems and species all around the world, Stroud has insisted that studies like this help us to build a new perspective. The results give a glimmer of hope that maybe, just maybe, such tropical and subtropical species are capable of tolerating extreme climatic conditions after all.

The study was published in the journal Biology Letters earlier this week and can be accessed here.

**

For weather, science, and COVID-19 updates on the go, download The Weather Channel App (on Android and iOS store). It's free!

Visit link:
Lizards in US Exhibit Rapid Adaptation to Colder Temperatures; Provide New Insights On Climate Change Resilience | The Weather Channel - Articles from...