Pat’s Wildways: Exotic Invaders

By Pat Foster-Turley, Ph.D.
August 5, 2021

Cuban tree frogs are an invasive species that consumes our native frogs, lizards and even small snakes. Notice their extra-large toe pads, one key identification sign. (Photos of frogs by Susan Gallion.)

Looks like its time again to post warnings about the strange invaders that are turning up more and more in our yards. Here in Florida we have the perfect climate for hitchhikers from tropical places to make a new life for themselves, and this new life presents new hazards to our established native species. Cuban tree frogs and the hammerhead worm are both making their presence known in our area and I’m sure that the cane toads will be next.

Although the Cuban tree frog has been on Amelia Island for quite some time now more people are recognizing it and taking appropriate steps to extinguish them. The main problem with this exotic invasive species is its consumption of our native green tree frogs, lizards and even small snakes and its ability to out-compete native frogs, even at the tadpole stage. Cuban tree frogs, like all tree frogs, have suction-like pads on their toes that enable them to stick to branches, windows and other surfaces. They are variable in color but often much larger than the green tree frogs many of us have become familiar with, with larger toe pads and often warty skin.

The University of Florida recommends humanely euthanizing any Cuban tree frog that you encounter, but be sure you have the correct identification and be careful since they can excrete a poison that can irritate your skin and eyes. To humanely kill a frog, wear gloves or a plastic bag over your hand and spray or rub benzocaine (a toothache and sunburn remedy) on them to anesthetize them, then put them in a bag in the freezer for 24 hours just to be sure.

Visit this site for more details before killing a frog and send the researchers photos if you are unsure. This site gives lots of useful information and encourages you to be a “citizen scientist” by reporting data on your find. And the more Cuban tree frogs that are removed from our environment, the more green tree frogs and other native species we will continue to enjoy in our yards.

Cuban Tree Frog, photo by Susan Gallion.

Do not confuse the invasive Cuban tree frog with another invasive frog that has made news in Florida. The cane toad originated in South America and has spread into south and central Florida, although not yet reported in Nassau County. These frogs also consume native species and outcompete others for food and resources. This large toad also secretes a toxin (bufotoxin) that is poisonous and can kill a pet that bites one in as little as 15 minutes. In the eventuality that they make it into our area be on the lookout and be prepared to kill them, humanely of course. But, again, Google for more information on identification—when they are small they look similar to our harmless native southern toads but they lack a crest between their eyes. And if it is larger than the 4” maximum size of our native toads, you’ve got one for sure. Be sure to report your find to Dr. Steve Johnson at the University of Florida ([email protected]) so he can add it to the range map if this time, sadly, comes.


Hammerhead worms, a terrestrial carnivorous planarian, poses a threat to our earthworms. (Photo by Cathy Currie Freeman)

Not all the exotic, invasive animals in our area are as visible as frogs are. One especially malicious species now inhabits our soil, underground, mostly out of sight, the hammerhead worm. This worm is not an annelid like our earthworms but instead is a terrestrial planarian, a strange creature that is sometimes said to be “immortal” since even small pieces of one that is cut up will regenerate into a complete new individual. Recently Cathy Currie Freeman, a homeowner along Heckscher Drive reported that a bunch of them surfaced in her yard after a hard rain, and she has warned others. The ones she photographed were about 3 inches long, but she has seen others much larger. And, in this photo she submitted you can see that the tail has been broken off—most likely this small piece has already become a new genetically identical worm, a scary thought.

Like the invasive frogs these invasive worms are a threat to our natural ecosystems. They eat the earthworms that fulfill a necessary ecological role by aerating and fertilizing our soil and eat insect larvae and other prey as well. And, like both frog species, they also secrete a poison, in this case a tetrodotoxin that is also found in the poisonous pufferfish. Similarly, the recommendations are to humanely kill them (although no one has specified how.) But whatever you do don’t cut them into pieces or your problems will multiply!

So, folks, be on the lookout for these unwelcome creatures, make the effort to properly identify them, and take the necessary action to remove them. Our native wildlife will thank you.

Pat Foster-Turley, PhD is a zoologist on Amelia Island. She welcomes your nature questions and observations. [email protected]

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Mark Tomes
Trusted Member
Mark Tomes(@mtomes)
2 years ago

This is valuable information. Thanks so much for posting it. On the plant side of things, we have a local volunteer group, the Invader Raiders, regularly getting together to remove Russian thistle, taro, air potato, Brazilian pepper, and other invasives from Amelia Island and the Talbot Islands. It is a fun group, and everyone is welcome for a one-time event or a more regular presence – your choice. Contact Kathy Russell at the Fernandina Beach City Parks and Recreation Department for more information. Together we can help keep our natural environment healthy and beautiful.