Lizards of Southwest Florida
Posted by Miqe on September 18, 2007
Lizards thrive in southern Florida’s subtropical environment. Their presence includes about 10 native species, but these are now outnumbered in Southwest Florida by at least 16 kinds of lizards from around the world.
Most lizards are relatively small and the largest (longest) of our native lizards are the glass lizards — lizards that have no legs, thus superficially appearing snake-like. The name glass lizard comes from their ability to leave their tail behind if grabbed by a predator — often leaving the predator with the tail while they escape.
This ability is characteristic of all lizards and one of the characteristics that separates lizards from snakes. Lizards also have external ear openings and most have eyelids that allow the animal to blink; snakes have neither. A lizard also generally has a long tail, while the tail of a snake is short — a difference that at first seems incomprehensible. It all has to do with how you define “tail.” The tail begins at the opening where waste and eggs or young pass out — and in lizards this is often midway on the underside of the animal, whereas in snakes it is very close to the end of the animal.
We have no venomous lizards in Florida and none that would attack a human. We do have some that can and will bite strongly to defend themselves if captured. The exotic Nile monitor, which can reach over 7 feet in length, is a lizard that poses a serious threat of bodily harm to those who would grab one.
Some of the exotic lizards, however, pose serious threats to native lizards, other native animals and native and non-native plants. A few cause other problems — such as iguanas that dig burrows in yards and sometimes short-circuit electrical systems. All (and most other creatures) have the potential of carrying salmonella, a bacterium that can make humans and pets sick, and some may be reservoirs for human illnesses such as West Nile virus transmitted by mosquitoes or ticks.
Jerome Jackson is host of “With the Wild Things” on WGCU/WMKO, 90.1/91.7 FM
A common native anole (pronounced: an o lee) throughout much of southeastern North America. These long-nosed, long-tailed, slender, often lime-green lizards change color with temperature and their mood, often turning a pale gray brown when it’s cold. They are sometimes called “chameleons” — a name that refers properly to a group of African lizards. Anoles are well known for their “dewlaps” or “throat fans” — colored patches of skin on the throat that they extend to defend a territory or attract a mate. The female lays tiny, white, jelly-bean-shaped eggs — but not all at once. She lays one egg about every seven to nine days (a total of about 15 to 18 eggs per summer). Each is buried in loose soil or mulch, or in material collected in depressions on tree surfaces. The female never returns to it, and six to eight weeks later the egg hatches and the tiny green lizard fends for itself, catching larger and larger insects as it grows.
The most common anole found in Florida today is an exotic invasive species from Cuba and the Bahamas that may have arrived as a stowaway with humans or goods traveling from those areas. It first appeared in the Florida Keys in the late 1800s and has expanded northward throughout the state and into Georgia, and across coastal areas of the Gulf states. Feeds on insects, spiders and much smaller lizards. Male and females are often easy to distinguish: males are usually darker and have a prominent crest from the back of the head down the spine; females lack this crest and are generally smaller. Lacks the ability to dramatically change color, although it can vary from a light brown to a very dark brown.
Western knight anole
The largest species of anole, sometimes reaching 18 inches in length. Scattered populations are known across southern Florida, including some in Collier and Monroe counties, and the species’ range and numbers are growing. These lizards are tree-dwellers, often basking high in the canopy. They change color with temperature and temperament — from green to a near chocolate brown. They feed on a greater diversity of small animals, including nestling birds and many other lizards. They’re relatively slow moving, but capturing one can be a problem because they have a very strong bite when threatened. Because of their size and green color, they are sometimes misidentified as iguanas.
Eastern glass lizard
Much like fragile glass, this lizard’s tail easily breaks off when predators attack, enabling them to make a clever escape. This is a characteristic of all of our lizards and their tails do grow back — sort of. It is a living-tissue “prosthesis” that serves many of the functions of the original tail. Florida has four species and three live in Southwest Florida. All tend to be straw yellow to bronze in color with some stripe pattern extending down the body. All are legless, leading to some misidentification as snakes. But these lizards have eyelids and can blink; snakes have no eyelids. They also have external ear openings; snakes do not. They can reach 28 inches in length, most of that being tail, and tend to be of a larger diameter than other glass lizards. These feed extensively on crickets, grasshoppers and other insects.
Can grow to 7 feet and feeds on virtually anything that moves — including such things as burrowing owl chicks and eggs, the eggs and young of gopher tortoises and many other small animals. A native of Africa, this is the most commonly sold monitor lizard in the pet trade. A hatchling can be purchased for as little as $10. Unfortunately, the baby monitor that feeds on crickets quickly graduates to mice and larger food — and develops a nasty disposition. A growing population in Cape Coral and elsewhere in Southwest Florida likely originated from pets released because they became too difficult to handle and feed.
Black spiny-tailed iguana
Since the late 1970s there have been growing populations on Key Biscayne on the east coast and on Gasparilla Island in Southwest Florida. The Key Biscayne population seems to have come from iguanas that escaped from Crandon Park Zoo. The Gasparilla Island population resulted from iguanas from Mexico that were deliberately introduced. The Gasparilla Island population has grown to at least several thousand and its numbers continue to grow — as has the realization that this iguana poses a threat to hibiscus flowers and other landscape plants, and to gopher tortoises and burrowing owls that compete for food and burrows. They’re good swimmers and some have made it from Gasparilla to the adjacent mainland and Cayo Costa. Large populations also occur now on Keewaydin and Little Marco Islands in Collier County.
A native of the American tropics and primarily a vegetarian, this iguana starts out at about 6 inches and can grow to 6 feet. It can breed at two years of age and females can produce as many as 50 eggs at a time, although only a few of their young survive to adulthood. In some recent years more than a million have been brought to the United States in the pet trade. Not surprisingly, some escape. Others are illegally released because an owner is tired of them. Because they are primarily vegetarians, these lizards pose little direct threat to native animals. But some south Florida populations now number in the thousands and this can mean trouble, because they love hibiscus flowers and other ornamentals, and consume many native and exotic fruits.
Found throughout Florida and much of the Southeast. Skink scales are tiny and smooth, giving them a shiny appearance. These have tiny, short legs and are rather secretive, but active by day and often bask in the sun. This skink often burrows into sand or loose soil or beneath debris. This is a ground-dwelling species of pine flatwoods, south Florida hammocks, backyards and piles of debris — rotting logs, tangles of decaying vegetation and other features that provide shelter and an environment rich in insects, spiders and other small invertebrates. Juveniles are conspicuous because of their bright blue tail and shiny black body with five narrow yellow to orange stripes.
The speedster of the Florida lizard community. These are the slender, long-tailed, yellow-striped lizards that race across dry, open sandy soil throughout the region. Unlike skinks and legless lizards, racerunner scales are not shiny. The six stripes for which they are named include three along each side. The stripes can range in color from pale blue to yellow, but are usually yellow. They feed on small insects, spiders, snails and other invertebrates, and are voracious feeders, doing a great deal of good in controlling pest species. Can grow to 9 inches, and are rather sensitive lizards, quickly racing off to take shelter if a human approaches.
Amerafrican house gecko
Among the exotic lizards now breeding in the wild in Florida are several species of geckos, including this one, which is increasingly common in homes throughout Southwest Florida. Geckos are known for unusual characteristics, including broad, “fringed-toed”-appearing feet that allow them to race across smooth ceilings and walls. Many gecko species have voices and males give audible chirping calls as they defend territories and interact. Many gecko females can produce young without mating — all clones of their mother. These geckos are harmless to humans and beneficial because of the numbers of insects they consume. They have wonderful eyes, which can narrow to a cat-like slit in bright light or open to reveal a most unusual octagonal pupil in dim light.