All Bark and No Bite? Not for Leopard Iguanas
- Sofia Valente
- Mar 22, 2023
- 3 min read
By: Sofia Valente
Leopard iguanas (Diplolaemus leopardinus) are just one of many species that rely on their surrounding environment to obtain heat. This is primarily due to the fact that they cannot produce their own heat like humans or other mammals do. Leopard iguanas are extremely vulnerable to climate change since their performance in the wild is reliant on their body temperature, which is influenced by the environment. Bite force is more influenced by their jaw muscles than temperature since the muscles that generate this force are intolerant against temperature changes. However, previous studies have indicated that body temperature does affect bite force in other lizard species. Vicenzi and her group of researchers wanted to study how the bite force and the total time Leopard iguanas can sustain a bite force greater than zero can be affected by increasing the temperature of their environment.
These researchers traveled to the Andes Mountains in Argentina where these Leopard iguanas are commonly found and they conducted both laboratory and fieldwork experiments. Vicenzi and her team captured 21 Leopard iguanas and recorded their body temperatures shortly after capture while also measuring the environmental temperature of the capture site. Once these measurements were recorded, all 21 iguanas were brought to a bioterium where their bite force and bite duration were measured using a pulse transducer that generates a voltage based on the applied force from the bite which was equipped with steel plates wrapped in leather to protect the iguanas’ teeth. Following this, they were then separated into 2 acclimation groups: iguanas that would live in a 20℃ environment and iguanas that would live in a 30℃ environment. The iguanas would live in these conditions for 2 weeks and once this time period had passed, all of them had their bite force, bite duration and body temperature measured again.
After recording all of the necessary data for bite force and bite duration for both acclimation groups, Vicenzi and her team of researchers found that the duration of the bites for the Leopard iguanas was not affected by changes in temperature of their environment. However, on a more exciting note, these researchers discovered that Leopard iguanas can actually bite harder in warmer environments! By having a stronger and more powerful bite, they have higher chances of catching better quality prey items but they would also have greater energy costs needed to survive. In addition, their “flight-or-fight” response would also change with a greater bite force since previous knowledge has indicated that these iguanas are more likely to flee in hotter temperatures and are more likely to attack in colder temperatures.
What we know thus far is that these wild Leopard iguanas from the Andes Mountains were successfully able to acclimate to a temporary environment with increased temperatures for 2 weeks. By the end of their experimental journey, Vicenzi and her group found that the bite duration was not affected by this increase in temperature but the bite force was affected in these creatures. These researchers suspect that thermal sensitive traits within Leopard iguanas are the plausible cause behind this physiological change in bite force. Although this alteration may seem beneficial, this may be the catalyst to their downfall since this change goes against their evolutionary adaptations thus, promoting reconstruction of their survival strategy. However, this realization could be the spark for other scientists to invest their time researching this phenomenon in other heat-seeking species or for environmental organizations to begin conservation projects and protect similar species that are susceptible to climate change. Only time will tell how long Leopard iguanas can withstand the impacts of climate change; otherwise, their situation will be too hot to handle! For now though, I guess it goes without saying that the idiom should be changed to “all bite and no bark” for these Leopard iguanas!
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