Its Raining Lizards
Correction: The challenge species is a black spiny-tailed iguanas (Ctenosaura similis) not a green iguana (Iguana iguana).
Over the last few years, Florida has seen a boom in green iguana (Iguana iguana) falling from trees.
But how did this species even arrive in Florida? Most likely as stow-aways on cargo ships, however, their ever-growing population is in part attributed to the pet trade. Over a million green iguanas have been imported into Florida since 1995. A non-insignificant number of those were likely released into the wild.
An even larger factor is that they face no natural predators in Florida and have access to an abundance of resources. Their size also allows them to push out native species. Additionally, Florida’s hot and humid climate is similar to its native range including the rain forests of northern Mexico, Central America, the Caribbean Islands, and Southern Brazil. However, inevitably, when the temperature drops into the low 50s this ectotherm struggles to maintain its internal body temperature leaving them paralyzed. If this happens while they’re in a tree, they lose their grip and fall off.
Green Iguana - Cayambe, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
Why do we refer to green iguanas as invasive vs nonnative?
Well, they’re both but invasive species typically harm the environment. Green iguanas are primarily herbivorous but have been recorded eating the Florida tree snail which is a part of Florida’s Imperiled Species Management Plan. They will also eat just about any plant, fruit, or flower which poses a problem for anyone with a garden or farm. Additionally, they dig burrows without permits leading to the erosion and collapse of sidewalks, foundations, seawalls, and more.
In April of 2021, Florida passed a rule that green iguanas could not be obtained by anyone living in Florida unless they had a special permit for research. Anyone already owning a green iguana had to get them tagged with a passive integrated transponder aka a PIT tag. These do not need a power source to work and can track the lizards. PIT tags also keep track of who the animal belongs to.
The great thing about the cold fronts paralyzing the iguanas is that this makes it easy for anyone trying to humanely remove them from the landscape, to capture them.
Can you #FindThatLizard?
Let me know in the comments with #FoundThatLizard.
Thank you to Ivel for submitting this photo!
If you would like more info for dealing with green iguanas in Florida, please use this reference.
