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9 Types of Invasive Monitor Lizards in Florida

Florida, also known as the “Sunshine State,” is famous for its beautiful beaches, theme parks, and unique wildlife. However, in recent decades, the state has faced a growing ecological challenge in the form of invasive species. One group of invaders that has garnered attention is the monitor lizards.

These large reptiles have established a presence in Florida, posing a threat to local ecosystems. This article explores the different species of monitor lizards that have been introduced to Florida and the environmental consequences of their presence.

Collage photo monitor lizards in Florida

9 Monitor Lizards in Florida

Florida’s subtropical climate and diverse ecosystems provide an ideal environment for many non-native species. Monitor lizards have been introduced to Florida either deliberately or inadvertently by human activities. The following is a list of monitor lizard species that have established populations in the state. 

1. White-Throated Monitor

White-throated monitor lizard
White-throated monitor lizard | image by Bernard DUPONT via Flickr | CC BY-SA 2.0

Scientific Name: Varanus albigularis albigularis

Native to Southern Africa, the white-throated monitor is known for its white throat markings. They can grow up to five feet in length and have become established in certain parts of Florida.

Like many other exotic species, they were likely introduced to Florida through the pet trade. They have a sturdy build, sharp claws, and a long, muscular tail.

2. Blue-Tailed Monitor

Blue-tailed monitor lizard
Blue-tailed monitor lizard | image by Hectonichus via Wikimedia Commons | CC BY-SA 4.0

Scientific Name: Varanus doreanus

The blue-tailed monitor is native to northern regions of Australia and parts of Papua New Guinea. These lizards are relatively small compared to some other monitor lizard species, with adults typically reaching lengths of around 2 to 2.5 feet.

They have dark brown or black bodies with cream-colored spots. But their most distinctive feature is their blue tails. 

3. Savannah Monitor

Savannah monitor lizard
Savannah monitor lizard | image by The Upstream Alliance via Flickr | CC BY-SA 2.0

Scientific Name: Varanus exanthematicus

Native to West Africa, these monitors are relatively small, reaching lengths of up to 2.5 to 4 feet. The females lay their eggs in burrows or other suitable locations, and the eggs incubate for several months before hatching. The young monitors are relatively independent from birth.

Savannah Monitors are popular in the exotic pet trade due to their manageable size and relatively calm disposition. This invasive species has been observed in some parts of Florida due to the pet trade. 

4. Peach-Throated Monitor

Peach-throated monitor
Peach-throated monitor | image by Cataloging Nature via Flickr | CC BY 2.0

Scientific Name: Varanus jobiensis

Another African native, the peach-throated monitor’s coloration can vary but often includes shades of brown and black with distinct peach or orange coloration on the throat, which gives them their name. This species of monitor lizard is native to New Guinea and some neighboring islands.

This lizard is medium-sized, measuring between 3 and 4 feet long. These lizards like to eat insects, small mammals, birds, and other reptiles. 

5. Nile Monitor 

Nile monitor 
Nile monitor | image by Bernard DUPONT via Flickr | CC BY-SA 2.0
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Scientific Name: Varanus niloticus

Native to sub-Saharan Africa, the Nile monitor is one of the largest lizard species in the world. These big reptiles can reach lengths of up to 7 feet, though that is rare. They have long, muscular bodies, strong limbs, sharp claws, and a long tail. Their coloration varies, but they typically have dark greenish to brownish-black bodies with yellow or cream-colored bands or spots.

Nile monitors are an invasive species in Florida. Their presence poses significant ecological concerns, as they can compete with native wildlife for resources, disrupt local ecosystems, and potentially prey on native species, including threatened or endangered animals.

6. Argus Monitor 

Argus monitor 
Argus monitor | image by Graham Winterflood via Flickr | CC BY-SA 2.0

Scientific Name: Varanus panoptes

Another non-native monitor species found in Florida is the argus monitor. These large lizards are typically between 5 and 6 feet long. Males are usually larger than the females.

They are typically darker in color with yellow or cream-colored markings on their bodies. Like other monitor species, they have strong limbs and powerful tails. 

7. Roughneck Monitor

Roughneck monitor
Roughneck monitor | image by James Jolokia via Wikimedia Commons | CC BY-SA 4.0

Scientific Name: Varanus rudicollis

The roughneck monitor is native to Southeast Asia, including countries like Indonesia, Malaysia, and Thailand. Roughneck monitors get their name from the raised scales or “roughneck” they have along their throat and neck region.

These monitors were introduced to the Florida ecosystem because of the pet trade. If you want to own a monitor, please do your research and don’t let it escape into the wild. 

8. Crocodile Monitor

Crocodile monitor
Crocodile monitor | image by cuatrok77 via Flickr | CC BY-SA 2.0

Scientific Name: Varanus salvadorii

Native to Indonesia and Papua New Guinea, the crocodile monitor is one of the largest monitor species. Measuring between 8 and 12 feet, this lizard is one of the biggest lizards in the world. Although they are not as common as some other monitors in Florida, their presence is a cause for concern. Their presence can cause a disruption in the ecosystem and needs to be closely monitored. 

9. Asian Water Monitor

Asian water monitor lizard
Asian water monitor lizard | image by Brian Gratwicke via Flickr | CC BY 2.0

Scientific Name: Varanus salvator

Asian water monitors are found across Southeast Asia. They are one of the largest lizard species in the world and can grow up to 6 to 9 feet. As the name suggests, water monitors are semi-aquatic and are often found in or near water bodies such as rivers, swamps, and coastal areas. These semi-aquatic lizards have also found their way to Florida, where they can thrive in a variety of habitats.

Ecological Impact

The introduction and establishment of monitor lizards in Florida have raised concerns among ecologists and wildlife experts. These reptiles are opportunistic predators and scavengers, capable of preying on a wide range of animals, including birds, small mammals, and even fish. This voracious appetite can disrupt local ecosystems by reducing the populations of native species and potentially causing imbalances.

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Furthermore, monitor lizards are known to compete with native reptiles for resources such as nesting sites and food. This competition can put additional pressure on already threatened or endangered species in Florida.

Efforts to Reduce the Impact

Recognizing the ecological threats posed by invasive monitor lizards, state and federal agencies and conservation organizations have initiated various efforts to mitigate their impact. These efforts include:

Monitoring and Research

Ongoing research to understand the behavior, ecology, and distribution of monitor lizards in Florida is essential for effective management.

Public Awareness and Education

Public education campaigns aim to inform residents and visitors about the risks of releasing or keeping non-native species as pets.

Removal and Control

Trained experts are working to remove established populations of invasive monitor lizards to prevent further spread.

Legislation and Regulations 

Establishing stricter regulations on the import, sale, and ownership of exotic pets, including monitor lizards, is being considered to prevent future introductions. The presence of invasive monitor lizards in Florida highlights the complex challenges non-native species pose.

While these reptiles may captivate some with their exotic appearances, their ecological impact can devastate local ecosystems. Efforts to control and manage these invaders are essential to protect Florida’s native wildlife and preserve the state’s unique natural heritage. Vigilance and proactive measures are crucial to ensure that the “Sunshine State” remains a haven for its residents and indigenous flora and fauna.