There was a frog visiting my kitchen window this morning, which isn’t particularly unusual. But this wasn’t a tiny, green tree frog like I grew up with. Those, by the way, seem fewer and fewer lately. This was a big critter — at least two and half-inches nose to tail — and a beige-y grey color. The first thing to come to my mind was “Cuban treefrog”. Could I be right? Have they made their way this far north? What makes them so undesirable? And what should I do about it?
It's not surprising that you would think of the Cuban treefrog. Much has been written lately about it and other invasive species. We sometimes focus on the plants that are displacing native species, but not as often do we talk about the animals that are doing the same.
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You’ve given a near-textbook description of the Cuban treefrog (Osteopilus septentrionalis). And, yes, they are native to Cuba, as well as the Cayman Islands, and the Bahamas — all areas warmer than North Florida. And, yes, they have migrated as far north as Duval County (range map available at ufwildlife.ifas.ufl.edu/frogs) And, again, yes, any frog larger than two and half inches is NOT a native Floridian.
Their color alone, however, is not enough to identify them. They can be white, gray, green or brown, and, to complicate things even more, can change colors. Their skin is bumpy with irregular warts. Their eyes are large and often described as “bug-eyed,” making them very obvious against the frog’s pale skin.
Cuban treefrogs are considered invasive because of the harm they do to our ecosystems and to humans. They eat at least five different species of native frogs, the occasional lizard and even small snakes. Your garden-guest is likely responsible in part to the scarcity you’ve noticed of “tiny, green tree frogs. The greenies became lunch. They also eat a wide variety of insects, many of them beneficial. Luckily, some native snakes, like our beloved rat snakes, black racers and garter snakes, help keep the Cuban treefrog numbers in check. Many birds also consider them tasty.
The skin of Cuban treefrogs secretes mucus that can burn your eyes and cause allergy-like reactionslike, sneezing or a stuffy/runny nose. Pets can also be affected. Luckily, there are no documented deaths or serious injuries of pets that have tried to eat a Cuban treefrog. However, pets that have tangled with these frogs have suffered excessive salivation and even seizures. It’s best to keep them apart, if you can.
Female Cuban treefrogs get quite big — 6 inches long or more — and have been known to short-circuit utility switches causing costly power outages and repairs. They sometimes take up residence in electric water pump housings and AC compressor units both around our homes and around commercial property. As their numbers increase, we can expect my serious and more expensive problems to arise.
Cuban treefrogs sleep during the day. In the wild, they will hide in tall pines, or in shorter trees and shrubs. In urban areas, they look for safety in tight, enclosed spaces, like the interiors of our homes where food is plentiful and places to reproduce are all around.
It is no wonder, then that their populations have become quite dense, and they have become a real nuisance. An unusually long period of cold temperatures in 2010 killed many Cuban treefrogs in peninsular Florida, but their numbers hopped back up soon after. Since we can’t count on cold weather to control them, it’s essential that we learn to do that ourselves.
There are three things homeowners can do to help curb the negative impact these animals are having. First, report the sighting. It’s important information for the University of Florida’s efforts to track the animals’ expanding territory.
Second, as harsh as it sounds, capture and humanely euthanize these predators. Be sure that you are positive it’s an invasive species and not one of our natives by visiting the UF/IFAS Wildlife website at ufwildlife.ifas.ufl.edu/cuban_treefrog_inFL.shtml. There you will find images of both Cuban treefrogs and native species. You will also find information about catching, identifying and reporting the spread of Cuban treefrogs. For complete details on humanely euthanizing these animals, go to edis.ifas.ufl.edu/uw259.
Third, eliminate the treefrogs eggs and disrupt potential breeding sites. Check your ornamental ponds and even your child’s wading pool for egg masses during the spring and summer, especially after heavy rains. Remove the eggs and any tadpoles you might find. This will also help eliminate breeding sites for mosquitoes.
One last note: Don’t confuse the Cuban treefrog with the Bufo toad (Rhinella marina), also known as a cane or marine toad. The cane toad is highly toxic to animals they bite or to pets who try to eat or play with them. according to the Florida Fish and Wildlife Conservation Commission. They, too, are highly invasive. Detailed information on the Bufo can be found at edis.ifas.ufl.edu/uw432.
Paula Weatherby is a Master Gardener Volunteer with the Duval County Extension Service and the University of Florida/IFAS. For gardening questions, call the Duval County Extension Office at (904) 255-7450 from 9 a.m. to noon and 12:30 to 3:30 p.m. and ask for a Master Gardener Volunteer.
