Unusually cold temperatures are sweeping across Florida, creating a potentially dangerous situation for the state’s non-native green iguana population. Overnight lows are forecast to reach the mid-30s Fahrenheit (single digits Celsius) or even the 20s F (negative single digits C) in some areas.
Iguanas and the Cold
Green iguanas (Iguana iguana) were introduced to the U.S. in the 1960s and have since thrived in Florida’s warmer climate. However, these reptiles are not equipped to handle temperatures below 50 degrees F (10 degrees C). The cold can induce a “cold shock,” and because iguanas often sleep in trees, this shock can cause them to become immobile and fall to the ground.
These lizards, which can grow to over five feet long, originate from the rainforests of Central and South America, where temperatures are much more stable. “These tropical lizards were experiencing conditions that they’ve never experienced in their entire evolutionary history before, tens of millions of years,” explained James Stroud, an evolutionary biologist at the Georgia Institute of Technology.
A Learning Opportunity for Scientists
While cold snaps in Florida are infrequent, they are becoming less common as overall temperatures rise due to climate change. These events provide a unique opportunity for scientists to study how animals respond to unfamiliar climates. Researchers, like Stroud, are interested in understanding the broader implications of these experiences.
A 2020 cold snap in Florida was the focus of research led by Stroud and his colleagues. Their findings, published in research, indicated that lizards that had previously experienced cold temperatures demonstrated increased tolerance to the chill. Stroud is now investigating whether this tolerance represents an evolutionary adaptation or a more temporary physiological response.
Should temperatures continue to fluctuate, it is possible that iguanas will continue to exhibit increased cold tolerance. It is also possible that populations may shift their behavior to seek shelter more effectively during cold snaps. However, the long-term effects of these events on the iguana population remain to be seen.
Frequently Asked Questions
What causes iguanas to fall from trees?
Cold shock can immobilize iguanas, causing them to lose their grip and fall from trees. This happens because they are not adapted to such low temperatures.
Are cold-shocked iguanas in danger?
Unless they fall from a significant height, cold-shocked iguanas are likely to recover once temperatures rise and they can warm up again.
When were iguanas first introduced to Florida?
Iguanas were first brought to Florida in the 1960s.
What role does climate change play in the future of Florida’s iguana population?
