Florida’s landscapes, renowned for their vibrant ecosystems, are increasingly home to a non-native species that has found the subtropical climate highly favorable: the green iguana. These large lizards, originally from Central and South America, have established significant populations across the state, particularly in southern Florida. Their presence is a result of releases and escapes from the pet trade, where they were once popular due to their attractive appearance. Now, these reptiles are a common sight in urban and natural environments, adapting readily to human-modified areas like suburban developments and canal systems.
Understanding Iguana Size in Florida
Green iguanas in Florida can achieve considerable sizes. Males are larger than females. Adult males can reach over 5 feet in length, including their long tail, and weigh up to 17 pounds. Exceptional males may stretch nearly 7 feet long and weigh up to 20 pounds, with the tail accounting for up to three-quarters of their total length.
Females can also grow to about 5 feet in length but typically do not exceed 7 pounds. Hatchlings are much smaller, measuring 4 to 6 inches long (excluding the tail) and weighing 2 to 4 ounces. They grow rapidly within their first three years, reaching full adult size. Mature male iguanas are also distinguished by prominent jowls and a large throat fan (dewlap), which are more developed than in females.
Influences on Iguana Growth
Several factors contribute to the substantial growth of iguanas in Florida. Florida’s warm, subtropical climate provides an ideal environment, enabling iguanas to remain active and grow year-round. This constant warmth extends their growing season, directly influencing their overall size.
Iguanas also benefit from an abundant and diverse food supply. As primarily herbivorous reptiles, they consume a wide array of plants, including shoots, leaves, blossoms, and fruits, often feeding on ornamental plants. While adult iguanas are mainly vegetarian, younger iguanas may occasionally supplement their diet with insects.
Another significant factor is the limited presence of natural predators for adult iguanas. Unlike their native ranges, adult iguanas in Florida face few threats other than humans, domestic dogs, and occasionally alligators. This reduced predation pressure, combined with their potential lifespan of up to 10 years in the wild, allows them to live longer and continue growing.
Ecological Implications of Large Iguanas
The large size and widespread presence of iguanas have significant ecological and infrastructural consequences in Florida. Their burrowing habits are destructive, as they dig extensive tunnel systems that can undermine the structural integrity of sidewalks, seawalls, foundations, and canal banks. These activities can lead to costly repairs and pose safety hazards, especially in coastal areas where seawall damage can contribute to erosion.
Iguanas also cause substantial damage to residential and commercial landscaping due to their appetite for plants, flowers, and fruits. Their herbivorous diet impacts native vegetation, including host plants for endangered butterfly species, and they compete with native wildlife for food and habitat. They may also consume bird eggs and young, disrupting local ecosystems.
Beyond environmental damage, large iguanas can impact human infrastructure. Their presence near power lines and transformers can lead to power outages. They also leave unsightly and unsanitary droppings on surfaces like docks, boats, and swimming pools, which can spread bacteria like Salmonella.