Cane Toads Multiplying Fast on Islands
September 23, 2021
The heavy rains over the last few weeks in southwest Florida have filled in many temporary or ephemeral wetlands. As with the native amphibian species, the exotic invasive anuran or frog species are taking advantage of many fishless bodies of water to breed and deposit eggs that will quickly become tadpoles that transform into miniature terrestrial frogs or toads.
The exotic giant toad ( Rhinella marina) also called the cane, marine, Bufo, or faux toad, has been aggressively breeding around Sanibel and Captiva in these wetlands. Each toad can lay up 30,000+ eggs (see photo below) but usually lay less than half of that.
Cane toads were first discovered on Sanibel during frog call surveys by SCCF in 2013. At that time, they were localized to a couple ephemeral wetlands near Middle Gulf Dr. and Fulger St. A quick response by SCCF, the J.N. “Ding” Darling Wildlife Refuge, and the City of Sanibel after detection showed promise in eliminating the new threat, but eggs were already deposited even though every visible breeding adult was collected. Now, cane toads are found throughout Sanibel and Captiva. The poison of the cane toad is lethal to most native wildlife species, as well as pet dogs and cats.
Sanibel also has one native species of true toad, the southern toad (Anaxyrus terrestris), that is easily differentiated from the exotic cane toad by size as adults, but nearly impossible as newly metamorphosized toadlets or under 1 inch. The main difference is that cane toads have a pair of very large triangular parotoid glands (poison glands) behind the eyes, bony ridges above the eyes, a more flattened face and can reach 6 inches in length.
Southern toads rarely exceed 3 inches; have small oval parotoid glands behind their eyes, a pair of cranial crests or ridges between the eyes on top of the head and a wider facial profile. The cranial crests on southern toads form after they are about an inch in length and toads smaller than that cannot be differentiated to species.
Concerned About Your Pets & Cane Toads?
So what should you do if you have these on your property and are worried about your pets or wildlife? Although eradication is not possible at this time, removal of adults from your property will certainly cut down on the numbers around you and therefore cause less risk for your pets outdoors and for wildlife.
The proper protocol for ethically capturing and euthanizing cane toads established by the American Veterinarian Association is to capture adults by either by hand (with a glove or using a plastic grocery store bag as a barrier) or wildlife tongs, after being positively sure it is not a native southern toad.
If using a plastic bag, grab the toad with the bag being used as a glove and pull the bag inside out so the toad is inside and tie it. Gently open the bag while holding the toad through the bag and apply lidocaine or benzocaine (ointment or spray) to the skin of the belly followed by freezing after 15 minutes for 24 hours. Click here to watch a video demonstrating how to euthanize at home. CROW will euthanize cane toads from Sanibel or Captiva if brought to them. Click here to contact CROW with any questions.