Forestry & Wildlife
Some invasive, species such as wild pigs and cogongrass, are well established across Alabama. However, did you know that there is a new invader hopping across the horizon? The Cuban treefrog (Osteopilus septentrionalis) is beginning to show up with greater frequency in the state, particularly along the Gulf Coast. These frogs aren’t native to the United States, but they have spread in great numbers across most of Florida and continue to expand beyond to other states in the south.
The native range of the Cuban treefrog includes Cuba, the Bahamas, and Cayman Islands. Although many reptile and amphibian invader are results of pet trade releases, this doesn’t seem to be the case with the Cuban treefrog. Instead it likely arrived to Florida ports through shipping crates. While they were first recorded in the 1920s, it took until the mid-1970s before they were found throughout southern Florida. With populations now established in Tallahassee and likely Pensacola, it is time that Alabama residents learned more about this frog threat and how they can help.
What problems could a treefrog cause anyway? When it comes to the Cuban treefrog, they can cause several problems. Cuban treefrogs reach maximum sizes far greater than any of Alabama’s native treefrogs. Because frogs are essentially a mouth and stomach with legs, this spells trouble for frogs and other small animals that have called Alabama home for millennia. It is well documented that Cuban treefrogs consume other frog species, particularly squirrel treefrogs, which is an Alabama native. In Florida, Cuban treefrogs have effectively replaced native treefrogs through competition and direct predation in the backyard and many other areas. Beyond this, the tadpoles have been shown to outcompete native tadpoles.
From a quality-of-life perspective, they cause issues, too. They frequently show up around outdoor lights, and their feces on walls and windows can be an annoyance. This species is also much more apt to seek shelter inside homes than native treefrogs. For those afraid of frogs, the chance of having an upsetting experience increases dramatically given their large size and natural inclination to live close to people. In the backyard, they may take over birdhouses, making the structure unsuitable for desired species like bluebirds. Although not as toxic as some invasive toads, they do have toxic skin secretions that have been known to cause pets to have seizures after biting them. Lastly, although uncommon, these frogs have also been documented congregating in electrical transformers and causing power outages.
Cuban versus Native Treefrogs
Alabama is home 15 species in the treefrog family and seven species in the genus Hyla, which people commonly refer to as treefrogs. Those seven can be distinguished from all other native frogs by their enlarged toe pads, which allow them to climb so well. So, how would someone know if the treefrog they found is a native one or the invasive Cuban treefrog? The following are a few tips to help make that distinction:
- Size. Any treefrog over 3-inches long is likely a Cuban treefrog.
- Toe pads. Cuban treefrogs have significantly larger toepads than native treefrogs.
- Eyes. Cuban treefrog eyes bulge more or appear more buggy.
- Head. For Cuban treefrogs, the skin is fused firmly to the skull for frogs over 1-inch long. Native treefrogs don’t possess this characteristic.
- Color/pattern. The color of Cuban treefrogs varies but is often off-white to light brown, sometimes with darker, wavy stripes.
Cuban treefrogs are still uncommon enough in Alabama that the state doesn’t have the same treefrog issues that Florida does. For this reason, it is important to remove any Cuban treefrogs seen in the wild. Although they may show up anywhere in the state, residents in Baldwin and Mobile counties should be on the lookout the most. To help keep Cuban treefrogs out of Alabama, take the following steps:
- If traveling back from somewhere that Cuban treefrogs are well established, check vehicles and boats before leaving and on return. Treefrogs are excellent hitchhikers.
- Do not release any Cuban treefrogs back into the wild.
- If capturing a Cuban treefrog, either use a plastic bag or wash hands immediately after handling to avoid effects from the noxious skin secretions.
- The most humane technique to euthanize a Cuban treefrog is to spread a 1-inch strip of benzocaine ointment on the frog’s back and wait until movement has ceased. Benzocaine ointment is available for oral pain relief at most pharmacies and grocery stores. After movement has ceased, transfer in a sealed bag to the freezer and leave it there for 24 hours. If this technique is not available, place the frog in the refrigerator for 3-4 hours before transferring it to the freezer.
- If Cuban treefrogs are around but difficult to catch, consider staking 5-foot lengths of 1.5-inch PVC pipe vertically into the ground near buildings and other structures. This is a technique scientists use to survey for treefrogs, because the frogs will use them as a refuge to hide in.
If a suspected Cuban treefrog is found, safely capture it and send photos to email@example.com or consider logging your sighting online at either iNaturalist or EDDMapS.