The American crocodile is a large carnivorous reptile which can grow to over 15 feet long and up to 2,000lbs. it is an at-risk species throughout its range in North and South America. There is not much information known about their population status except for in the United States, but illegal hunting and habitat loss are two factors that are heavily influencing the populations.
American crocodiles have a global status of “vulnerable”, which means that this species is likely to become endangered unless the circumstances that are threatening the species survival and reproduction are improved. In Florida, the northern most extent of the American crocodile’s range, laws have been put in place to protect the American crocodile and there has been improvement in the reproduction and survivorship which has led them to be state listed as Threatened.
There are 22 species of crocodilians found in the whole world, of these species only 13 of them are crocodiles, and only two crocodilians are found in the United states - the American alligator, and the American crocodile! In the U.S. the American crocodile thrives in the mangrove swamps, bays, and creeks of Florida and tends to spend the winter months further inland than during the summers and breeding season.
The population in Florida, however, is quite a small portion of the crocodiles range. A majority of the population lives in southern Mexico, Central America, the Caribbean, and the northern portions of South America. A recent push has begun in Jamaica to protect the American crocodile, which is an amazing step for their conservation. One of the tools being used to conserve this species is to educate residents with “Croc-Wise” – an educational outreach program targeting communities and schools. This program will help to inform residents about the natural history of the crocodile, their preferred habitat, and to help prevent human-crocodile conflicts from occurring.
This is a huge step, considering a VICE article written in 2016 (https://www.vice.com/en_us/article/8ge4yv/the-rogue-conservationist-trying-to-save-jamaicas-alligators) which discusses how decades of development has destroyed much of the habitat for the crocodiles, overfishing has depleted the food sources of the crocodiles, and a surge in demand for crocodile meat has led to increased poaching (which is still a big issue now in 2019). At the time this article was written the government had not shown much interest in protecting the crocodiles and one individual, Lawrence Henriques, who had taken it upon himself to help the crocodiles out in any way he could.
The National Environment and Planning Agency (NEPA) is managing the American crocodile population in Jamaica. The management includes a crocodile rescue and research operations committee which are a combination of efforts from NEPA the Hope zoo, and several other NGO's and private individuals. Together they relocate nuisance animals, perform research and general assessments of the crocodile population, and formulate policies and strategies to create effective management plans. All conservation efforts will hopefully keep these creatures from going extinct, and create a happy environment for the crocodiles and human beings to be able to coexist peacefully. To learn more about the American crocodile more information can be found at the link provided below:
The Burmese Python (Python bivittatus), is a snake that is found naturally occurring in a large area of tropical South and Southeast Asia. Their average lifespan in the wild is 20-25 years (NationalGeographic.com), grow to be 16ft-23ft in length, and can weigh an upwards of 200lbs. These snakes are very popular in the pet trade and can be purchased quite easily throughout the United States. Here in Florida, however, they have become a nuisance. Between raging storms destroying warehouses and freeing the captive pythons, and careless owners releasing their pets into the wild once they reach an unmanageable size, the Burmese python has an established population in south Florida – mainly in the Everglades.
Well over 2,000 pythons have been removed from the Everglades National Park (ww.nps.gov) since 2002. This is only a tiny portion of the population that is present down here in south Florida. The pythons have inflicted a devastating impact on the ecosystem in the Everglades – feasting on the native birds, mammals, and reptiles found in the ‘glades. This includes the previously endangered Wood Storks, which are currently listed as a “threatened” species (and are imperiled in the state of Florida). Below is an image showing what a Burmese python needs to consume in order to grow to be 13ft.
Two formal python management programs have been established in south Florida. One program is through the South Florida Water Management District, and the second is through Florida Fish and Wildlife Conservation Commission (FWC). These programs were begun in order to enhance python removal in south Florida by specifically targeting areas and effort for the removal of the pythons, which has been one of the most successful way to remove pythons to date.
FWC Python Removal Contractor Program (PRCP)
This program was developed to involve qualified individuals with python management. These individuals must be experienced with the capture and removal of nonnative constrictors through a previous python permit obtained through a FWC python challenge event, work through a national park or preserve, or as a contractor for the South Florida Water Management District python program. They must also not have any previous violations on any FWC issued permits or wildlife-related citations and project a positive image of FWC and the python program at all times. These hunters also assume all liability for health, welfare, and safety of themselves and those assisting them.
The contractors are paid between $8.46/hour - $15/hour depending on the location that they survey. Each python nest is worth $200, and every python removed is $50 for the first 4 feet, and another $25 for every foot after the first 4 feet.
For more information on the FWC python program:
South Florida Water Management District Python Elimination Program
The South Florida water management district python elimination program began in March of 2017. This program is geared towards members of the public who are capable of identifying removing and youth and Ising pythons in Miami Dade, Hendry, Collier, Palm Beach, and Broward County from SFWMD lands in South Florida.Within this program over 2000 pythons have been removed to date. a majority if these snakes have been Under 4 feet, and only 3 have bee over 17 feet. Compensation for SFWMD hunters is comparable to the compensation provided by FWC. This program is limited to 25-35 participants, and is not currently accepting applicants.
This elimination program targets the following species:
Burmese Python (Python bivittatus)
Northern African Python (Python sebae sebae)
Reticulated Python (Python reticulatus)
Southern African Python (Python sebae natalensis)
Amethystine/Scrub Python (Morelia amethistina)
Boa Constrictor (Boa constrictor)
Yellow Anaconda (Eunectes notaeus)
Green Anaconda (Eunectes murinus)
Beni Anaconda (Eunectes beniensis)
DeSchauensee’s Anaconda (Eunectes deschauenseei)
For more information on the SFWMD Python program:
For article written about the hunters and hunting programs above:
Large python capture:
Python hunting program:
The central American river turtle, also known as the Hickatee, is a species that is critically endangered according to the IUCN red list. Their population trend is decreasing in the wild, making them of extreme concern for conservation. Historically this turtle is the only surviving species of a family of turtles which used to be wide spread. However, now this turtle is restricted to parts of Central America, Southern Mexico and Guatemala. It is a large freshwater turtle that is nocturnal highly aquatic and completely herbivorous feeding only on plant matter. Unfortunately due to its large size it has been hunted in its range and over exploited for centuries. This over exploitation has led to the critically endangered status of this turtle and reduced its populations to the point where it is likely that they may become extinct.
Habitat and Reproduction
These turtles tend to live in deep rivers and lakes and a travel using areas that are flooded during the wet season. As the floodwaters recede they will occasionally become trapped in small ponds and lakes until the next wet season occurs and floods allow them to travel back to the deeper rivers. Not much is known about the reproduction of these turtles. Females of the species like to nest at the peak of the wet season and can lay up to a for clutches of eggs. Not much is known about the nesting and reproduction of the species due to the low numbers of populations, how fragmented they are in Central America, and the lack of research done on them. It is known that the nests are often laid below high water points and often flood for weeks, but this flooding of the nest is not shown t cause any kind of negative impacts on the survival of the hatchlings.
Hunting and over exploitation
The biggest threat to these aquatic turtles is over hunting of mature turtles and their eggs. This turtle has been hunted since the time of the Mayans and Hickatee with rice is a traditional meal that is widely eaten, especially in Belize, to this day. It is relatively easy to hunt the hickatee since it is inactive during the day time and when sold at market can bring in much profit. There are laws in place that the hunting of the turtles to be illegal in Central America since 1975, but there is a lack of enforcement which leads to the over exploitation of what populations are left.
Research and conservation
There has been some research done on these turtles, but not much is known about them. They have not had a formal population assessment throughout their range in years, and studies are extremyl difficult to perform due to lack of funding and since they have a highly fragmented population. There is a need for sites and areas to be protected to protect these turtles resources and habitat. Protection to is needed for their food sources and the water quality of the homes that these turtles live in. Management of the areas where the Hickatee is found, as well as restoration of some natural processes in highly developed areas. Species management and recovery plans are heavily needed in order to direct conservation efforts including species reintroduction where they have been exploited and conservation in the form of captive breeding and head starting. Other efforts for education include formal classroom education, training and awareness, and communications in the community where these turtles are being hunted and exploited. Encouragement for compliance and enforcement of laws to protect this animal is also heavily needed. It is also suggested that further research be done on the actual population size distribution and trends within those populations how often these turtles are harvested what they are used for and how they contribute to the livelihood of locals who are harvesting them as well as general population trends throughout their range.
CrocFest is a non-profit organization that raises money twice each year for the research and conservation of various crocodilians. This is a wonderful fundraising event that I am always so excited and proud to participate in. Earlier this December the winter 2018 CrocFest fundraising event was put on at Gatorama - a home to predominantly crocodilian residents, Gatorama provides captive housing for various crocodilians including American alligators, American crocodiles, Saltwater crocodiles, Nile crocodiles, and many more. In addition to the main attraction, this facility houses various tortoises, lizards, and snakes for entertainment and educational purposes. Gatorama generously opened their doors to be the platform and location for winter CrocFest to occur, and donated all admission to the park directly to the CrocFest cause.
Winter CrocFest 2018 raised money and awareness for the Indian Gharial. The Indian Gharial is one of only two species of it's kind, and it is suffering tragic decline. The beneficiary of the funds raised this year go to Jeff Lang. Dr. Lang is a world rebound crocodilian biologist who taught Animal Behavior and Vertebrate Zoology at the University of North Dakota for over 20 years and has headed various research projects focusing mainly on crocodilians and turtles.
In 2008 there was a mass die-off of over 110 Indian Gharials. This tragic event sparked the Gharial Ecology Project (GEP) headed by Jeff and another biologist in India, Romulus Whitaker. Together they obtained some funding to radio track Gharial in the area where the mass die-off occured in order to see how this even influenced reproduction of the species along with other aspects of their ecology. Jeff has been directing this effort as an unpaid volunteer, paying for his airfare and expenses for three trips a year since 2008 and training dedicated staff for the project.
His efforts to date have ruled out some of the potential obvious causes for the Gharial die-off included tainted food sources and pollution of habitat. This suggest an event specific to Gharials - disease, genetic mutation, or potentially response to stress. The research has document movement of size classes from hatchling to adult, males and females, daily and seasonal patterns of movement which are all important towards understanding the life of Gharials and allowing scientists to identify key factors to move the species towards recovery.
The money raised at CrocFest goes directly to Jeff and his research group in order to further fund the research and conservation of this amazing g species.
CrocFest is broken up into two parts:
Silent auction, and live auction. The wonderful event has gracious donors and caterors whom provide beverages, food, and servers for the event. These tasty delights are there to enjoy while attendees mingle amongst th8emselves, look at auction items, and enjoy exhibits.
These auctions, in addition to t-shirt sales and the price of admission, are the main method to raise funds. All auction items are donated by wonderful supporters of crocodilian conservation and research. Items this year ranged from ZooMed and Zilla reptile tanks and accessories, authentic clothing and decorations from India, beer, jewelry, decorative plates, live reptiles and arachnids, custom artwork, food, alcohol, knives, tickets to various Florida attractions and much much more.
The silent auction goes from event start until 5PM, at which point the highest bidder takes their winnings. After the silent auction items have been claimed and donations collected it is time for the main event: the live auction. The rules are simple- if you raise your hand, scratch your head, or get outwardly excited over an auction item you make a bid....its all for conservation, remember? Highest bid takes all, and even the auctioneer can bid things out from the crowd. This is quite a lively event, and battles to outbid one another can escalate quite dramatically (and quickly).
The important part of CrocFest is to remember that ALL proceeds go directly towards research and conservation of wonder crocodilian species in need. This year winter CrocFest raised over $40,000.
Everyone loves a happy beginning
CrocFest will continue to raise money and awareness for crocodilian research, and has already announced its summer 2019 CrocFest event which will take place in June 2019 at Zoo Miami in southern Florida.
The Madagascar day gecko is yet another specie that has been introduced into the wild in the state of Florida. These reptiles belong to the gecko family, the genus (classification of animals) Phelsuma, and the species madagascariensis, These cool green geckos reside on the island of Madagascar, and they usually live in rainforest trees. The Madagascar day gecko is one of the largest species of day geckos, and can grow to be just under 9 inches in length. They are a green-blue color with brown-brick red spots down their backs, and a similarly colored stripe from their nostrils to behind their eye. While these geckos are mostly found in the trees of the rainforest, deforestation has caused them to lose much of their usual habitat, and they have been known to dwell in villages and live inside the huts and banana trees on the eastern coast of Madagascar as a result. These brightly colored creatures eat insects and fruit (but only if it is soft!), and have been known to eat pollen and nectar as well.
Madagascar Day Geckos are very common in the pet trade, and they are easily kept and bred for sale in the United States. Usually housed alone, these lizards can be very territorial and even male-female pairs will occasionally fight. They thrive in 50-60% humidity and 80-90 degrees Fahrenheit, making them perfectly suited for Florida weather. Day geckos were first reported as being seen in Florida in the 1990s. There is one population in one county which has been reported as sustainable and breeding on their own, and have been sightings in three other counties where breeding has not been reported.
The most established population of day geckos is located in the Florida Keys. They are seen on white mangroves, buttonwood trees, buildings, and other man-made structures near mangrove estuaries. They were first reported outside of the Keys, in Broward county in 1999. These animals were confirmed as released or escaped pets, and the population in the Keys is a result of a single introductory event. Due to their popularity in the pet trade, and the suitability of Florida weather, a pet breeder released many adult individuals with the intention of having them breed and he harvests the hatchlings to be sold as pets.
This is another great example of how easy it is for nonnative animals to become established in areas where they do not belong. The geckos do not appear to have an adverse impacts on native Florida wildlife, however species such as the Argentine tegu and Burmese python were released and are wreaking havoc on native animals in Florida.
There are over 40 different species of day gecko, but the Madagascar day gecko is one of the most well known species. Below are photo of other day gecko species:
Photos Provided by: https://www.arkive.org/ and https://www.flickr.com/photos/cas_docents/
For more information on Day Geckos in Florida:
Florida Museum Report
Rehoming a pet can often times be difficult to do, especially for no-so-furry-friends, but Florida is trying to make it a bit easier. The Cooperative Invasive Species Management Areas (CISMAs) along with Florida Fish and Wildlife Conservation Commission (FWC) have come together to hold an even called Exotic Pet Amnesty Day. During this event people are able to drop off their pet and it will be found a new home with a pre-approved adopter.
This day gives people an alternative to releasing their exotic pet into the wild. When exotic pets are released into natural environments they can cause disruptions which are damaging to the ecosystem. Some examples of the havoc released pets can cause are the Burmese python and the Argentine black and white tegu in the Florida Everglades. These two species have populations in the wilds of Florida which originated from released or escaped pets. They both eat many native animals, and this impact can be seen in the decline of mammals throughout areas where pythons are present in Florida. The tegu, a known egg-eater, threatens the protected American Crocodile, ground nesting birds, and turtle species including sea turtles.
The early set up allows for pet owners to drop off and register their animals for adoption. Two Golden thread turtles that were dropped off to be adopted are pictured below. The Amnesty day accepts all types of animals, from sulcata tortoises to parrots to all kinds of snakes. Every animal that is surrendered gets a visual examination by a volunteer veterinarian. The vet will give the animal a quick examination to assess what condition it is in and if it can be adopted out. The below pictured Veiled chameleon receives a vet examination. The veiled chameleon can be found in populations scattered throughout south and central Florida, all of which are suspected to be human released individuals.
After the vet gives the animals a clear bill of health they are set along tables with information about their previous home – their species, name, age, sex, any of their quirks for the new owners to be aware of, toys and food preferences, and any notes from the vet. When the surrender period is over, the adopters are allowed to walk the line of tanks and cages to see what animals are available to be adopted. After the viewing, each adopter is randomly assigned a number, and those numbers are randomly drawn to give the order adopters may chose the animal(s) they wish to bring home. Once every adopter has had their chance, the hope is that every animal surrendered has been taken to a new home. Any animal not selected at the event is taken to a holding facility, and a notice is sent to approved adopters to find them a home with people who may not have attended the amnesty day event.
It is a happy new beginning for every animal and adopter who attends. The most recent pet amnesty day was held in West Palm Beach, Florida on the 19th of August 2018. I was able to volunteer at this event, and saw dozens of animals surrendered. Red-eared slider turtles, yellow belly slider turtles, golden thread turtles, Russian tortoises, hamsters, cockatoos and cocktails, just over a half dozen ball pythons, and even prairie dogs! It was amazing to see just how many candidates were brought in to be put up for adoption. Every animal that was given up was taken home by the end of the adoption event.
Since 2006 this Pet Amnesty Day program has been very successful at rehoming animals that are no longer desired, difficult to care for, or are unable to be cared for. Below are annual summaries of each Amnesty event in Florida - I hope the totals continue to rise as the years go on.
Learn More about Pet Amnesty Day...
Monk Parakeet, Quaker Parrot
The Monk parakeet, which is also commonly called the Quaker parrot, is a bird which grows to be approximately 11 inches in length from tail tip to top of head, and has bright green coloration with a grey breast and green-yellow belly. This bird originated from temperate and subtropical areas of Argentina and other surrounding countries in South America. This is a very common bird, which has expanded its native range as eucalyptus forestry industry also expanded. The forestry industry provided artificial forest habitat for the parrots to nest with little competition from other species for resources.
In the pet trade, these parakeets are known to make wonderful companions due to their ability to develop a wide vocabulary of words and phrases. These critters are anything but quiet, and are quick to learn mimicry and perform tricks when they are motivated by treats and praise. They are also available in a variety of color mutations including blue and “cinnamon”.
Although they are such wonderful pets, the Monk parakeet is actually banned for sale in many states. This bird has established feral populations in Spain, Portugal, Azores, Madeira, Balearic Islands, Gibraltar, France, Corsica, Malta, Cyprus, Sardinia, Italy, Greece, Channel Islands, Great Britain, Ireland, Belgium, British Columbia, Canada, Brazil, Mexico, Israel, Bermuda, Bahamas, Cayman Islands, Easter Island, Puerto Rico, South Korea, Japan, and the United States. Thousands of parakeets were imported to the USA in the 1960s-1980s (Lund, Nicholas. "The Monk Parakeet: A Jailbird Who Made Good". Audubon. Audubon. Retrieved 9 December 2016.), and many escaped or were intentionally released which cause several established populations to occur across seven states. The most prolific population exists in Florida, with estimates of 150,000 to 500,000 individuals (Gorman, James (8 September 2004). "Birds do it, bees do it ..." San Diego Union Tribune. New York Times News Service. Retrieved 9 December 2016.) Due to being seen as a pest, the parakeet has been banned for sale in California, Georgia, Kansas, Kentucky, Hawaii, New Jersey, Pennsylvania, Tennessee, Wyoming, and Western Australia.
This invasive bird has been growing exponentially, with no show of slowing down until 2016. They have very few natural predators, diseases or other factors that would limit their population growth. Although they are thought to be agricultural pests, the real concern with Monk parakeets revolves around their massive nesting aggregations. The Monk parakeet builds its nest from sticks, and often are seen to breed in colonies where they will collectively build one large nest with multiple entrances for the various pairs of birds utilizing the space. Some of these collective nests have been seen to reach the size of small cars! These birds live to be 15-20 years old in the wild and as captive pets (Fasbach, Laura (23 July 2001). "A squawk in the park". Edgewater Online. Archived from the original on 28 September 2007. Retrieved 12 January 2008.). They often nest on man-mad structures including electrical poles and cellphone towers, causing them to have a heavy impact on electrical companies in several states. The most common method of control is through the removal of nests and trapping of the birds. There is also reproductive control possible through contraception, which is a long-term, non-lethal population management strategy.
Hello all! Last year you may remember a blog post I made on the impacts of Argentine black and white tegus where they are introduced in Florida. Since last year there has been some further development on what tegu species are residing in Florida, what the tegus are eating, and how easy it is to accidentally lose a beloved (and expensive!) pet.
As a quick recap of my previous post: the Argentine black and white tegu is a large lizard native to South America – specifically Brazil, Paraguay, Uruguay, and Argentina. These lizards can reach up to four feet in length, spend most of their time on land, but can swim and remain submerged for long periods. These critters are intelligent, and when kept as house pets can be very attached to their owners and quite docile – making them wonderful pets. However, as the tegu grows very large it can become more work than their owners care to give, many owners and individuals who sell animals in the pet trade become irresponsible and release their Tegu into the wild. Occasionally, beloved pets are lost when not kept in a secure outdoor enclosure, not watched appropriately, or accidentally get loose and run away.
Currently there are three species of tegus in Florida – the Argentine black and white tegus (Salvator merianae), Gold tegus (Tupinambis teguixin), and Red tegus (Salvator rufescens).
The Argentine black and white tegu is the most apparent of all tegus in Florida. They have established populations in south Florida and central Florida, which occurred from two separate incidents of introduction. In the past year it has been seen that these tegus eat many vertebrate species including lizards, turtles, birds, rodents, and snakes in addition to native and nonnative plant species and insects. They pose a huge threat to ground nesting birds, American Alligators, and American Crocodiles, as they love to consume eggs. The Argentine tegus also have a “morph” or a genetic combination that is seen in the pet trade called a “Blue Tegu” which have also been seen in south Florida. These Blue Tegus are thought to be escaped pets, which range from $300-$400 in retail price at pet stores, while regular black and white tegus retail for under $200. Althought they are of special color morph, these blue tegus are still Argentine black and white tegus which means they can survive and damage the natural ecosystems in Florida.
The Gold tegu is very similar to the Argentine tegus. They are from South America, and have been trapped in Florida since 2008. They can grow up to three feet in length, and usually live in the tropical forests of northern and central South America, and Panama. In their native range they are known to feed on insects, invertebrates, small mammals, reptiles, birds, fish, and fruit. This means they are likely eating similar item sin Florida, although nothing is currently known about their dietary habits. What is known about the Florida population is that they are reproductively active. Hatchling, juveniles, and adults have been captured over the past decade. It is theorized that the Gold tegus have been introduced via the pet trade industry. To read more about the Gold tegu in Florida this paper by J. Edwards et al. is a great place to start! These animals retail for approximately $50, but they are also not as commonly kept as pets due to their naturally aggressive temperament.
The red tegu has been seen recently in the popular video on social media posted above! Quite a wonderful companion. This is one of the largest of the Tupinambis species and usually grows to be four feet in length or longer. They are powerful tunnelers and love to dig where they are native. They use these burrows for refuge during the day and night, as well as shelter for their eggs. They are known to eat birds, rodents, eggs, and other reptiles - making them another prime candidate for impacting the environment in Florida! There have been a total of eleven sightings since 2007 that span through seven counties in Florida. The Red tegu goes for a retail price of $200-$300, and for this reason it is also thought that the animals seen were escaped pets.
All three species of tegus go through brumation (reptile hibernation), where they reduce activity and resign to burrows for the cooler months of the year. This is one of the many reasons why tegus are such a formidable invasive animal in Florida! They have potential of surviving much further north than even the Burmese python. As you can see, these animals do cost quite a pretty penny. The red tegu, Argentine Tegu, and Blue tegus all retail for $200 or more, and it is common to see household pets brought in from neighborhoods, parks, and other urban areas. They are great diggers and will escapes outside enclosures, porches, fences, and even harness/leash if they put their mind to it! The most commonly encountered tegu are still wild Argentine tegus, but it is interesting to see what other morphs and species are also present in the Florida ecosystem! I hope you all have enjoyed the update.
About the Author: Jenna is a graduate student at the University of Florida. Currently she is studying Wildlife Ecology and Conservation while working in south Florida to manage invasive animals. Jenna primarily works with the Argentine Black and White Tegu and other invasive lizards.
The Common Agama, Rainbow Lizard
The Common Agama is native to Africa and can comfortably occupy urban, suburban, rural and undeveloped habitats. In Africa they occur in desert, dune, savanna, forest, rainforest, and mountainous areas. This lizard is yet another non-native species that can be found in southern Florida. They occur in Dade, Charlotte, Broward, and Seminole counties; likely posing threat to native insect and small vertebrates. There are several subspecies of agamas, and Florid has a mixture of West African subspecies and East African subspecies. The West African subspecies have bright orange-red heads that fades to a blue-indigo body, and end with a lighter blue-white tail tipped with black. They can reach up to 12 inches in length and are a diurnal species which can be seen moving around during the daytime.
The diet of these lizards consists of mostly grasshoppers, ants, beetles (James and Porter 1979), flowers, grasses, and discarded human food (e.g., candy, bread, cake, carrot pieces (Romer 1953, Chapman and Chapman 1964, Harris 1964, Cloudsley-Thompson 1981). Adults have also been known to eat their own young. They display behaviors similar to that of Bearded Dragons – the adults will perform head nods, head bobs or push-ups, and basking. The head nods and head bobs are commonly used as challenge displays between males, or to entice females who are wearing their reproductive colors. Basking is common in the morning between 10 AM and noon, with the dominant males holding the best basking position, followed by the sub-males, and then females.
Female agamas will lay two clutches of eggs each breeding season, usually between the months of June through September. The sex of the eggs is determined by the temperature of the soil, with males being produced in warmer temperatures than females. In Florida the lizards are established and have been breeding for at least ten years in Charlotte and Dade county, and for less than ten years in Broward, Seminole, and Martin counties; there is also a population in Monroe county which has not yet been reported as breeding.
Links and papers:
Chapman, B. M,. and R. F. Chapman. 1964. Observations on the biology of the lizard Agama agama in Ghana. Proceedings of the Zoological Society of London 143:121-132.
Clodusley-Thompson, J. L. 1981. Bionomics of the rainbow lizard Agama agama (L.) in eastern Nigeria during the dry season. Journal of Arid Environments 4:235-245.
Harris, V. A. 1964. The life of the rainbow lizard. Hutchinson Tropical Monographs. 174pp.
James, F. C, and W. P. Porter. 1979. Behavior-microclimate relationships in the African rainbow lizard, Agama agama. Copeia 1979:585-593.
Romer, J. D. 1953. Reptiles and amphibians collected in the Port Harcourt area of Nigeria. Copeia 1953:121-123.
Iguanas have become one of the most common invasive reptile seen in southern Florida. You can find them in trees, crossing streets, eating the flowers in your garden... Two of the more well known species of iguanas in Florida are pictured below - the Black Spinytail Iguana (Photo by Jeff Whitlock, 2013) and the Green Iguana (Photo by Save the Prairie Society, August 3, 2017).
Black Spinytail Iguana (Ctenosaura similis)
This species is native to southern Mexico, and was first noticed in Florida in 1978. Currently it has established its self breeding populations in Dade, Lee, and Charlotte counties in Florida. Adult males of this species can reach four feet in length, and females remain smaller. These lizzards are primarily terrestrial species, and are extremely wary of humans. When they feel threatened these iguana will retreat to their burrows for safety, however they are able to climb quite well if they are unable to safely reach their burrow (Bartlett and Bartlett 1999).
The habitats that this iguana is able to exploit are very broad. They can be found living on coastal uplands, in exotic plant communities, low density suburban developments, agricultural fields, and areas surrounding core urban areas and small towns. Over the years this species has spread across south Florida. First thought to be established in Lee county (1980), then Collier county (1998), and finally Broward county (2002); this species was introduced due to released or escaped animals intended for the pet trade.
The distribution of Black Spinytail Iguanas in Florida, 10 February 2018.
Green Iguana (Iguana iguana)
The Green Iguana is a large lizard that is also nonnative to Florida. This species, like the Black Spinytail Iguana, was introduced through the pet trade as well. The Green iguana lives terrestrially, and can be seen on the ground and in shrubs and trees all over suburban developments, urban areas, small towns, and agricultural areas. They are excellent swimmers, can tolerate fresh and salt waters, and can remain under water for up to four hours at a time. Male Green iguanas can grow over five feet in length and weigh just under 20 lbs, while females usually do not exceed 7 lbs at full maturity.
Originating in Central America to the tropics of South America and some eastern Carribbean islands, the Green iguana was first reported in Florida in the 1960s in Hialeah, Coral Gables, and Key Biscayne. Now the popualtions spread along the Atlantic coast in Broward, Martin, Miami-Dade, Monroe, and Palm Beach Counties; along with the Gulf Coast in Collier and Lee counties.
Distribution of the Green Iguana in Florida (EDDMAPS, 10 February 2018)
Status in Their Native Ranges
Although the Green Iguana has not been formally assessed in its native range, both it and the Black Spinytail Iguana are listed as being of least concern where they originate from. This means that they are exhibiting characteristics of a healthy population that is reproductively active and not exposed to any threats which may cause them to become threatened, endangered, or extinct.
Diet and Impacts
The diet of the iguanas includes a wide variety of vegetation. They are known to eat shoots, leaves, blossoms, and fruits of plants including nickerbean, hibiscuses, garden greens, jasmine, orchids, roses, Washington fan palms, squashes, and melons. They also occasionally feed on bird eggs, carrion, insects, and tree snails.
Due to their diet, iguanas pose a threat of damage to residential and commercial landscape vegetation and are considered a nuisance animal by property owners. They are most attracted to trees with fruit and flowers, with the exception of citrus. The dig burrows, which can erode and collapse sidewalks, foundations, sea walls, berms, and canal banks. They pose a threat to native and endangered species of tree snails, as well as have the potential to spread diseases and infectious bacterium Salmonella to other reptiles and to humans through water contact or surfaces contaminated with feces.
Iguanas can be legally removed year round with land owner permission. They are not protected by any laws except for the anti-cruelty laws. Florida Fish and Wildlife Conservation Commission (FWC) encourages the removal of Green iguanas on private land by landowners, and captured iguanas can be kept as personal pets or humanely euthanized. The iguanas cannot, however, be relocated and released at other locations.
In order to deter iguanas from your own property you can alter the habitat around our home ot humanely harass the animals until they leave. Some effective methods are: removing plants that act as attractants; filling in holes to discourage burrowing; putting wind chimes or other items in the yard to make intermittent noises; hanging CDs or other reflective material outside; and spraying the animals with water.
Iguanas in the Florida Keys
Dealing with Iguanas
Iguana Assistance for Homeowners
About the blog
Ferrets and Friends, LLC has four writers bringing you information on a variety of topics from pets to wildlife, education to conservation, and from new developments in our business to information about our industry. Learn something new each week!