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Toxic Cane Toads Making Comeback on Islands
Despite initial hopes that Hurricane Ian had eradicated the islands’ invasive giant toads, also known as cane toads (Rhinella marina), they are making a comeback. Residents are reporting sightings and expressing concern due to their toxicity to cats and dogs.
According to the Florida Fish & Wildlife Commission, the skin-gland secretions of cane toads, which are called bufotoxin, are highly toxic and can sicken or even kill animals that bite or feed on them, putting native animals and domestic pets at risk.
The bufotoxin may also irritate the skin or burn the eyes of people who handle them. Cane toad eggs also contain bufotoxin and can harm or kill native animals that consume them.
How cane toads got to the islands
Cane toads are an exotic, invasive species that was discovered on Sanibel in 2013 during summer frog call surveys, these invaders were likely brought to the island by accident in sod, fill, or plants.
“We had hopes that Hurricane Ian would have eradicated the population with the storm surge,” he said. “Although it took nearly six months for a sighting, they were found to still exist on the island.”
Their post-Ian survival relates to another common name for them — marine toad — due to their higher salinity tolerance.
When they were first identified 11 years ago, they were very localized at a site off of Middle Gulf Drive. Torrential rain that filled up several ephemeral wetlands caused a breeding frenzy that was noticed by SCCF’s frog survey team.
“It was all hands on deck to remove as many of these breeding adults as possible, because the best and only time to eradicate most invasive species is early, right after detection,” said SCCF Wildlife & Habitat Management Director Chris Lechowicz. “Unfortunately, eggs were already deposited in several areas, so the removal of every adult seen had little effect.”
Each female can lay between 4,000-36,000 eggs, making eradication extremely challenging.
After they were first discovered in 2013, cane toads quickly spread across the island and all the way up to South Seas Resort on the north end of Captiva within several years.
Identifying cane toads
Unfortunately, they look very similar to the southern toad (Anaxyrus terrestris) which are often misidentified when they are at the same size. Cane toads get much larger (6 – 9 inches) than southern toads (1.5 – 4 inches) and have several physical characteristics that differentiate them such as large parotoid glands, cranial crests that outline the eye (as opposed to being interior), and an elongated snout (hence being in the family of beaked toads).
“Larger juveniles and adults of these two species are not hard to differentiate, however toadlets or newly metamorphized toads are practically identical,” said Lechowicz.
How to Safely Remove Cane Toads
Since there is no best answer for eradication, the best way to control cane toads on your property is to remove adults when you see them. This will minimize the number of toads that successfully lay eggs and populate your property.
Toads are attracted to bright lights at night and often hide behind garbage cans because both of those attract prey that they eat. That is a good time and place to locate them.
The most current, ethical, and recommended euthanasia method is to rub or spray 20% benzocaine (toothache gel), sunburn spray, or Lidocaine on the toad’s lower belly. This causes the toad to become unconscious. Then, place it in a sealed baggy and put in the freezer, disposing it after 24 hours. Of course, you should wear gloves and avoid rubbing your eyes, nose, or mouth during this process.
Please be advised that no local organizations will take your unwanted cane toads.
If you have questions about correct identification, please email info@sccf.org.