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The Origin of Brown Basilisks

The introduction of the Brown Basilisk in the United States, particularly in South Florida, is believed to have occurred around the 1970s. Primarily associated with the pet trade, these exotic creatures were imported for their unique looks and abilities. However, due to various circumstances, including unintended escape and intentional release, they found their way into the wild.

The tropical climate of South Florida closely mirrors the Brown Basilisks' native habitat in Central and South America. This, coupled with an abundance of food and lack of natural predators, has allowed them to establish a stable and increasing population in the region.

Although the Brown Basilisks have demonstrated remarkable adaptability, their presence raises ecological concerns due to the potential competition with native species for resources and habitat. Therefore, their population and impact are closely monitored by conservationists and wildlife authorities.

Male brown basilisk on a cypress knee in South Florida

Eagle Trail, Grassy Waters Preserve, West Palm Beach, Florida by Jessica Baker

Physical Characteristics

Brown Basilisks (Basiliscus basiliscus), or the common basilisks, are a sight to behold, featuring several unique physical traits that set them apart.

Size and Weight:

Adult brown basilisks typically range from 24 to 30 inches in length, including their long, whip-like tail, which makes up over half of their total length. The males are generally larger and heavier than the females, with the males weighing up to 500 grams, while females usually weigh around 200 to 300 grams.


True to their name, Brown Basilisks exhibit a range of brownish hues. Their bodies are generally brown to olive with black and white crossbands, although this coloration can vary somewhat. The belly is lighter, usually a pale yellow or cream color. Their coloration helps them to blend into the vegetation and stay hidden from potential predators.


One of the most distinctive features of the Brown Basilisks is the presence of crests. Males possess a tall dorsal crest that extends from the back of their head to nearly the end of their tail. They also have a crest on their head and another one under their throat. Females also have crests, but they are significantly smaller and less conspicuous than those of males.

Eyes and 'Third Eye':

Brown Basilisks have large eyes with a keen vision, which is crucial for spotting predators and prey. Uniquely, they also have a light-sensitive patch, often referred to as a 'third eye' or a parietal eye, on the top of their head. This 'eye' doesn't provide clear vision but can detect changes in light and dark, alerting them to overhead threats.

Legs and Toes:

Brown Basilisks have strong, muscular legs, particularly their hind limbs. Their toes are long and fringed with scales, which trap air and create surface tension that prevents them from sinking into the water while they run.

The Brown Basilisks' Journey to South Florida

How did they get to South Florida?

The presence of Brown Basilisks in South Florida is not a natural occurrence but rather a result of human intervention, specifically through the pet trade. Whether by accident or design, some of these pet Basilisks found their way into the wild. Accidental escapes could occur during transportation or from the homes of pet owners. In other cases, pet owners intentionally released the lizards into the wild, often because they became too large or difficult to manage.

Why South Florida is an Ideal Habitat

Once introduced to the wild, Brown Basilisks discovered an environment in South Florida that was strikingly similar to their native habitats - a warm climate, plenty of water, abundant vegetation, and a wide range of food sources. These factors, combined with a lack of natural predators, allowed the lizards to establish and expand their populations rapidly.

While the pet trade has since implemented stricter regulations, the established populations of Brown Basilisks continue to persist in South Florida. Their presence underlines the significant impacts that the pet trade can have on local ecosystems and the importance of responsible pet ownership and trade practices.

The Life of Brown Basilisks in South Florida

Diet and Predation

Being omnivorous, they consume a varied diet including insects, small mammals, fruits, and flowers. Their predators include birds of prey, snakes, and large mammals.

Reproduction and Life Span

With a fast-paced life, Brown Basilisks reach maturity at one year, reproduce multiple times a year, and have a life span of about 7-8 years in the wild.

Adaptations to the Environment

Brown Basilisks have adjusted well to South Florida's environment. They're known for their ability to run on water to escape predators, using their long toes and unique fringes.

Impact of Brown Basilisks on the South Florida Ecosystem

As non-native species, Brown Basilisks have the potential to significantly affect South Florida's ecosystem. Their impact can be examined in several ways, including competition with native species, predation, and potential changes to local biodiversity.

Competition with Native Species

Brown Basilisks, being omnivorous, consume a wide range of food, including insects, smaller lizards, fruits, and flowers. This varied diet can lead to competition with native species for resources, particularly for food and nesting sites. The high adaptability and reproduction rate of Brown Basilisks can potentially put pressure on local species.


In their role as predators, Brown Basilisks might contribute to controlling the population of certain species, such as insects and smaller lizards. However, they could also pose a threat to native species that are not used to such predators.

Changes in Biodiversity

While the introduction of a new species can sometimes increase local biodiversity, it can also pose a risk if the non-native species becomes invasive, disrupting existing ecological relationships and processes.

It's important to note that while Brown Basilisks have established themselves in South Florida, they're not currently considered an invasive species due to their limited range and the lack of evidence for significant impacts on local wildlife and habitats. However, monitoring their populations and potential impacts is an ongoing task for local wildlife agencies.

Also noteworthy is the role of Brown Basilisks in educating the public about the impacts of the pet trade on local ecosystems, leading to better regulations and practices. Their presence can serve as a reminder of the importance of responsible pet ownership and the potential consequences of introducing non-native species into new environments.

Other Basilisk Species in the US

The Brown Basilisk is not the only member of its genus found in the United States. Another basilisk species, the Green Basilisk (Basiliscus plumifrons), also known as the "plumed basilisk" or "double crested basilisk," is present, albeit less common than the Brown Basilisk.

Like the Brown Basilisk, the Green Basilisk was also introduced through the pet trade and found its way into Florida's wilds. However, its distribution is much more limited compared to its brown counterpart. One potential reason could be its need for a more specific habitat compared to the more adaptable Brown Basilisk.

Although both Brown and Green Basilisks are non-native, they are now considered naturalized species in South Florida. However, potential ecological impacts, including competition with native species and predation, are ongoing areas of research.

While these are the only basilisk species known to have established populations in the United States, it's important to note that the pet trade continues to import a variety of exotic reptiles, highlighting the need for continued monitoring and regulation to maintain ecological balance.

Where to next?

Unveiling the Secrets of the Florida Bonneted Bat
An Introduction to the Ocklawaha River – A Journey Through Time and Conservation
The Perdido Key Beach Mouse: A Tiny Guardian of Florida’s Dunes
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