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10 Invasive Lizards of Hawaii

All of the lizards found in Hawaii today are introduced species brought over by humans, intentionally or accidentally. Some of the most common lizards in Hawaii include the common house gecko, the Cuban anole, and Jackson’s chameleon. While these lizards may seem harmless, they have had a significant impact on the local ecosystem and pose a threat to native species.

Tokay Gecko

tokay gecko
Gerard Chartier, CC BY 4.0 via Wikimedia Commons

These geckos are one of the largest species alive today, with males ranging from about 13-16 inches and females about 8-12 inches. They are easily recognisable by their bright blue-grey skin with red spots and their distinctive call, which sounds like “to-kay, to-kay!”

Tokay geckos are native to Southeast and East Asia but have also been introduced to many other parts of the world, including Hawaii. In Hawaii, they are widespread and can be found in various habitats, including rainforests and urban environments, especially near buildings.

Tokay geckos are nocturnal, meaning they are most active at night. During the day, they hide in crevices and other dark places to avoid predators. They are also arboreal, meaning they spend most of their time in trees and other high areas.

Regarding diet, tokay geckos are carnivorous and will eat a variety of insects and other small animals. They are known to be particularly fond of crickets but will also eat spiders, cockroaches, and other small lizards.

Tokay geckos are oviparous, meaning they lay eggs rather than give birth to live young. The incubation period is normally 60 days, and the hatchlings are entirely independent of the moment they emerge from the eggs.

Mourning Gecko

mourning gecko
Tim, CC BY 4.0, via Wikimedia Commons

The mourning gecko is a small lizard that has made its way to the Hawaiian Islands. It is believed to have arrived even before the first Hawaiians due to its widespread occurrence in over 20 regions bordering the Indian and Pacific oceans.

They measure only 2.25 inches from snout to vent. It has a slender body with a pointed snout and large eyes. Its skin is smooth and has a pale brown or greyish-brown colouration. The gecko has a distinctive dark stripe from its eyes to its shoulders.

One surprising thing about the mourning gecko is that it is an all-female species. It reproduces through parthenogenesis, meaning the females can produce offspring without mating with a male. This has allowed the species to spread rapidly throughout the Hawaiian Islands.

It prefers to live in urban and suburban areas, where it can find plenty of food and shelter. It is often found in homes, where it can feed on insects and other small invertebrates.

Common House Gecko

This tiny lizard is native to Southeast Asia but has been introduced to Hawaii and other areas worldwide. The gecko is usually only a few inches long. They are typically grey or light brown, with white undersides. They have large, round eyes and sticky toes that allow them to climb walls and ceilings.

Common house geckos are found all over Hawaii, from urban areas to forests. They spend their days hiding in crevices and under leaves. They are most active at night when they come out to hunt for insects.

While common house geckos are beneficial in their native habitat, they are considered an invasive species in Hawaii. They have displaced native gecko species and are believed to be responsible for the decline of some bird populations.

Gold Dust Day Gecko

gold dust day gecko
Jjboffy, CC BY 4.0, via Wikimedia Commons

The gold dust day gecko is a brightly coloured lizard native to Madagascar but has been introduced to Hawaii. It is one of the most common geckos found in Hawaiian households, where it is often seen climbing walls and ceilings in search of insects to eat.

It is a small gecko, measuring between 8 and 12 cm in length. It has a bright green or yellowish-green body, with some rare bluish specimens. Its body is also dotted with red markings on its neck and back, a trait typical of the day geckos. It has large eyes with vertical pupils and sticky toe pads that allow it to climb smooth surfaces like glass and metal.

In Hawaii, it is well established in localised areas on Oahu, Hawaii, and Maui, where it is found on large trees and palms in suburban neighbourhoods. All Hawaiian populations stem from eight lizards released by a student on the University of Hawaii campus in 1974.
The Hawaii Department of Agriculture prohibits importing and possessing the gold dust day gecko without a permit.

Madagascar Giant Day Gecko

Madagascar giant day gecko
Charles J. Sharp, CC BY-SA 4.0, via Wikimedia Commons

Madagascar giant day geckos can grow up to 30cm long. They are brightly coloured, with green bodies and red stripes on their faces and legs. As their name suggests, these geckos are native to Madagascar. However, they have also been introduced to Hawaii and other Pacific islands. In the wild, they live in rainforests and other wooded areas.

Madagascar giant day geckos are primarily insectivores but will consume nectar and fruit. These geckos are diurnal, meaning they are active during the day. They spend most of their time in trees and other high places.

Jackson’s Chameleon

Jackson's chameleon
Movingsaletoday edited by Muhammad, Public domain, via Wikimedia Commons

This species of chameleon is native to Kenya and Tanzania, but it was introduced to Hawaii in the 1970s. Since then, it has become one of the most common chameleons in the state.

They are bright emerald green, fading to a yellowish colour on their undersides. Males are 10-12″ long, with a long, prehensile tail that accounts for half of their length and three horns protruding from their forehead.

In the last 30+ years, Jackson’s Chameleons have multiplied and formed a large breeding population in Oahu, Maui, Kauai, and Hawaii. In particular, they can be found in the Koolau range, Oahu. They thrive in various habitats, including forests, gardens, and suburban areas.

They can prey on native Hawaiian species, including snails and insects. As a result, they can harm the environment.

Veiled Chameleon

veiled chameleon
Σ64, CC BY 4.0, via Wikimedia Commons

Veiled chameleons are not native to Hawaii and were introduced illegally through the pet trade. They are popular pets due to their unique appearance and colour-changing ability. However, they pose a threat to the native Hawaiian ecosystem.

They have a high reproductive capacity and can prey on native birds and insects. They are also adaptable and can tolerate living in various environments, from dry sea level areas to very wet montane areas up to 12,000 feet elevation.

Males can grow up to 24 inches long, while females are around 12 inches long. In the wild, they eat insects but can also eat fruit and vegetables in captivity. They are native to the Arabian Peninsula and are adapted to live in hot and dry environments

Green Anole

green anole
Lauren McLaurin, CC BY 4.0, via Wikimedia Commons

These lizards are not native to Hawaii but were introduced accidentally in the 1950s due to a rapid increase in demand in the pet trade. Since then, they have become successfully established on many islands in the Pacific, including Hawaii.

The green anole is easily recognisable by its bright green colour, which can change to brown or grey depending on the environment. They have a long, pointed heads with ridges between the eyes and nostrils and smaller ones on the top. The toes have adhesive pads to facilitate climbing and exhibit sexual dimorphism, with males being fifteen per cent larger than females.

Green Anoles are arboreal, meaning they spend most of their time in trees, bushes, and other vegetation. They feed on insects such as crickets, grasshoppers, and moths.

Brown Anole

brown anole
Don Loarie, CC BY 4.0, via Wikimedia Commons

The brown anole is a species of lizard that is not native to Hawaii but has become established on all the islands. They are originally from Cuba and Hispaniola, and it is believed that they were introduced to Hawaii accidentally via imports of plants with soil containing brown anole eggs.

Brown anoles are 5 to 8.5 inches long and have a light brown colour with darker brown to black markings on their back. They have several tans to light colour lines on their sides, and like other anoles, they can change colour from darker brown to black. Their dewlap ranges from yellow to orange-red.

Brown Anoles are often found in open habitats such as urban areas, plantations, and gardens. They thrive in tropical environments and occasionally pose risks to native wildlife.

They can breed extremely quickly, and their populations in certain areas can explode within a few short years. Females lay a single egg at a time and can lay up to 20 eggs per year. Brown anoles are insectivores that feed on insects, including ants, beetles, and grasshoppers. They will also eat small lizards and spiders.

Knight Anole

knight anole
Richard Stovall, CC BY 4.0, via Wikimedia Commons

The knight anole should be in Cuba and the Bahamas but it was introduced in the 1950s. In Hawaii, the knight anole is considered an invasive species and can be found on several islands, including Oahu, Maui, and Hawaii.

The knight anole is a large lizard, with males growing up to 13 inches in length. They have a distinctive green colouration, with a white or pink dewlap (a flap of skin under their chin) to communicate with other lizards. They also have a long tail that they can use to balance themselves on branches.

Knight anoles are arboreal lizards, which means they spend most of their time in trees. They are found in forests, gardens, and parks. They are active during the day and are often seen basking in the sun on branches or rocks.

The knight anole is a carnivorous lizard and feeds on various insects, including crickets, grasshoppers, and beetles. They are also known to eat small lizards and birds.