Beware Of This Invasive Frog That Could Be Lurking In Your Yard

It’s not a novel invasion: The Cuban treefrog (Osteopilus septentrionalis) was first found in the U.S. about a hundred years ago. Since then, this frog has made its way across Florida and other locations across the Southeast. “Cuban treefrogs are a problem because they eat native frogs and compete with them for habitat and food, impacting biodiversity,” says Steve Johnson, PhD, professor of wildlife ecology and conservation at the University of Florida. “Their numbers are rising, but we really don’t know how many there are.”

Native to Cuba, the Cayman Islands, and the Bahamas, Cuban treefrogs also seem to be expanding their range, hitchhiking their way to other states on ornamental plants from nurseries, or on cars, trailers, and boats. “We’re not 100 percent sure where established populations are, but we have reports of them in coastal Georgia and Louisiana. They’re likely also to be found in coastal Alabama and Texas,” says Johnson. “They could be anywhere in the Southeast where it’s mild enough so they can persist.” 

Understanding Cuban Treefrogs

Cuban treefrogs hide in crevices and protected areas around homes, such as behind shutters and siding. In both forested and suburban settings, they eat local native species and appear to be responsible for declines of some native treefrog species, such as the squirrel treefrog, says Johnson. Even the immature stages, or tadpoles, of Cuban treefrogs prey on the tadpoles of native species.

Cuban treefrogs may find their way indoors through roof pipes and can clog sinks, showers, and toilets as they search for moisture. So, yes, you may be surprised to open your commode and find one staring up at you! Their breeding calls aren’t clamorous, but they can be annoying in the wee hours of the morning if they’re hanging out near a bedroom window. They’ll also soil homes with their feces as they climb up on exterior walls and windows to eat insects, says Johnson.

 When handled, these treefrogs secrete a sticky toxin as a defense, which can be irritating to mucous membranes of people or pets who make contact with them. Although the Cuban treefrog’s toxin is not lethal to pets like the secretions of the invasive cane/ bufo toad, they still may your pet diseased or cause excessive salivation, says Johnson.

Identifying Cuban Treefrogs

Learning to distinguish these frogs from native treefrog species is significant.  “Cuban treefrogs can be challenging to identify,” says Lisa Thompson, spokesperson for the Florida Fish and Wildlife Conservation Commission. “Their skin can range from tan or light gray to olive green. Some also have patterns on their backs, while others are a solid color.”

Cuban treefrogs range in size from 2 or 3 inches up to 6 inches. They have obvious bulging eyes and immense toepads. Their most obvious identifying feature is that they have lots of warts of various sizes on their backs. However, they do not have warts on their heads. “If you want to support native biodiversity, learn to identify these frogs accurately and differentiate them from native species,” says Johnson.

Cuban treefrogs are mostly nocturnal. During the day and during arid weather, they may be found hiding out in pipes, basements, tree cavities and other areas that offer moisture and shelter, says Thompson.

What To Do About Cuban Treefrogs In Your Garden

It may not be possible to eradicate these frogs on your property, but you can take certain steps to make your yard less welcoming:

• Never handle these frogs with your bare hands. If you do touch them, wash your hands thoroughly. Also, keep pets away from them, and call your vet ASAP if your pet has mouthed one.
• Cover stand pipes on the roof to prevent the frogs from moving down into your plumbing, says Johnson.
• Remove standing water. Cuban treefrogs tend to lay their eggs in compact artificial water sources, such as buckets, bird baths, ornamental ponds, clogged gutters, rain barrels, flower pots, kiddie pools, and water troughs. Emptying these water sources also will facilitate eliminate mosquito breeding sites.
• Destroy eggs and tadpoles found in these locations. The eggs appear as a film of black, evenly-spaced specks on the water’s surface. They may be floating in groups or in one immense “raft.” Tadpoles are about 1 ¼ inches long with eyes on the sides of their heads and tails that are obscure above and creamy-white below. If you find eggs or tadpoles in an artificial body of water, it is likely the Cuban treefrog. Dump out the water, which mimics the natural process of a breeding pond drying out before a tadpole can metamorphosize into a frog, says Johnson.
• Monitor ornamental ponds for egg masses in spring and summer, especially after bulky rains. Scoop out with an aquarium net and dump on the ground.
• Maintain swimming pools so they’re not a breeding site.
• Check birdhouses because these frogs like to hide out in them.
• Report a siting. Because it’s well-documented that the frogs are found throughout the state, it’s not necessary to make a report if you discover one in Florida, says Johnson. However, if you live outside of Florida, report it here to facilitate scientists track their distribution.
• Consider removal. In order to support and be an advocate for native species, scientists suggest humane removal of these frogs. If you don’t feel comfortable doing so yourself, contact a nuisance wildlife operator.
• Stay vigilant. “This isn’t a once-and-done operation,” says Johnson. “You will need to maintain your yard and periodically check for these frogs.”