Possible Population Boom for Cuban Treefrogs, an Invasive Threat to Florida: What You Can Do About It

Photo of a Cuban Treefrog. Photo by pondhawk on Flickr

With their big round eyes, often pudgy little bodies, chirping sounds, and tendency to hop everywhere they go, a lot of people might consider frogs cute. However, the Cuban treefrog’s invasive threat to the United States as a whole and to Florida, especially after the recent hurricanes, makes it a lot less cute.

As the name suggests, these frogs hail from Cuba, but they are also native to the Cayman Islands, San Salvador, Acklins Island, and other places in the Bahamas. Yet, according to the United States Geological Survey (USGS) on a table that was updated as recently as November 21, they are also currently invading 36 states and US territories.

The USGS believes that these frogs were “introduced through horticultural shipments and plantings (especially palm trees), hidden in building materials, and hitch hiking on motorized vehicles”. 

The first recorded encounter that the USGS had with Cuban treefrogs in the U.S. was in Maryland in 1927. The first recorded encounter in Florida was in 1931.

Florida has had official scientific observations of the Cuban treefrog through the USGS as recently as April 2024. In total, these frogs have been observed on scientific expeditions in 57 separate locations in Florida, which is at least 41 more than any other state.  

According to the University of Florida (UF), Cuban treefrogs are a non-native “threat to the biodiversity of Florida’s native ecosystems and wildlife” because they “are SO successful at taking over habitat and eating Florida's native species”. 

The USGS says that they have an “insectivorous/carnivorous diet” that can include small vertebrates like other frogs, tadpoles, and lizards. They will go after prey up to twice their size. 

UF refers to the frog species’ appetite as “voracious” because once people have “first noticed a Cuban treefrog in their yard”, they will also begin to notice “the gradual disappearance of the other frogs, toads and even lizards…and unfortunately they eat Florida's native frogs, toads, and lizards, in addition to insects and spiders”.

Furthermore, the Cuban treefrog’s breeding season just ended in October, several weeks after two major hurricanes struck Florida. The USGS notes that the ideal breeding conditions for this species include a warm air temperature around 80 degrees Fahrenheit, high humidity, and rainy weather. 

The USGS also calls them “a storm-adapted species that can immediately increase its fecundity and rapidly disperse during and after hurricanes” and that is “very tolerant of saltwater”. 

The resulting clutches can be “very large”, averaging around 4,000-5,000 eggs. Regrettably, this means that these frogs could be experiencing a population boom in the wake of the hurricanes. 

Regarding the appearance of adult frogs, Cuban treefrogs grow an average of 1-4 inches in length, but some can grow longer than 6 inches, especially females, making them a large kind of treefrog and the largest in the U.S. Their skin can be unpatterned or heavily-patterned and they can be a wide range of colors, including “gray, tan, brown, bronze, olive-green to blue-green”.

Photo showing a color variation for the Cuban treefrog. Photo by pondhawk on Flickr

Adding to that, Cuban treefrogs have blue bones, which can sometimes be seen through their transparent skin, especially for younger frogs. This species also tends to have much bigger, more bulbous toe pads that are the size of their eardrums. 

Photo illustrating the size and shape of the Cuban treefrog’s toe pads in relation to eardrum size. Photo by pondhawk on Flickr

In addition, unlike “U.S. treefrogs, the dorsal skin”, or back skin, on adult Cuban treefrogs, “is fused to the skull; this is a defining character of the species”. As for juveniles, they “are difficult to distinguish from indigenous U.S. treefrogs because they lack ‘warts’ and exhibit very little pattern; however, they lack the light or dark lateral stripe found on some treefrog species”.

The call of the Cuban treefrog is also distinctive and has been described as a similar sound to “a high-pitched snoring rasp”. UF provides an audio clip here.

If you find a frog that fits the description above, then UF says that the best way to confirm whether it is a Cuban treefrog “is to grasp the frog firmly, but gently, and try to move the skin around on the top of the frog's head with your fingertip”. If the skin does not move, then it is a Cuban treefrog. 

Since Cuban treefrogs are so destructive, secrete a “noxious chemical” that is toxic to humans and pets through their skin, have been observed functioning as intermediate hosts for rat lungworm, have been found to carry other diseases, and more, UF recommends euthanizing them on sight and provides humane methods for doing so. 

Once you have identified the suspect as a Cuban treefrog by testing if its dorsal skin is fused to its skull, you can apply benzocaine ointment to its back, preferably with gloves on, or you can use benzocaine spray. Then, “place the frog in a plastic grocery bag or a sealable sandwich bag for 15-20 minutes so that the benzocaine has a chance to render the frog unconscious (be sure to seal the bag or tie it closed)”.

This will anesthetize the frog, so it will not feel discomfort. After that, the bag needs to be placed in the freezer overnight before it can be disposed of in the trash. If you do not have any sort of benzocaine products, then you can skip that step and place the frog directly into a bag and put the bag in the freezer.

UF says that “Freezing is a humane way to kill amphibians because their bodies go into a state of torpor (metabolism slows way down) -- just as they do in cold weather outside. If the cold weather is short in duration, the frogs will come out of their torpor state. However, after an extended time in freezing temperatures, the frogs die”.

No matter what, if you handle a frog, especially a Cuban treefrog, be sure to wash your hands afterward. Even if gloves were used, the frog’s skin secretions may have gotten on you, and these secretions can be an irritant to human skin and eyes.
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Article by Ema Tibbetts