It's not a snake – Mysterious legless, eyeless amphibians surface in Tamiami Canal
The discovery was a shocking experience – in more ways than one.
When state biologists making a routine survey zapped the Tamiami Canal in Miami-Dade County, up floated a caecilian. (Scientists use electricity to learn what waterbodies hold: A quick jolt stuns submerged wildlife so they can be counted at the surface before they revive.)
A rare South American amphibian never before seen outside captivity in the U.S. let alone Florida, caecilians (pronounced "Sicilians") normally inhabit the Orinoco basin, a huge watershed that includes much of Venezuela and eastern Colombia.
The one that turned up in the canal in 2019 was about two feet long, though some grow to about five feet, and stumped the researchers who found it. They kept it in a tank, where it survived for a while, but it didn’t eat and eventually died.
Meanwhile, an email query reached University of Florida scientist Coleman Sheehy III, who manages the Museum of Natural History's herpetology collection. He quickly IDed it as a member of the Caecilian genus, a branch of the group that also contains frogs, toads and salamanders, but its species remained a mystery.
“It was right before the pandemic,” Sheehy recalls. “Everything stalled, so it sat in a freezer for a long time before it could be transported up here to Gainesville.” Once it arrived, Sheehy took a tissue sample to sequence the critter’s DNA.
Turns out it was Typhlonectes natans, known as the Rio Cauca caecilian. Occasionally sold as pets (Sheehy suspects that’s where the Tamiami Canal specimen originated), captive-bred Caecilians generally sell for between $300 to $1,000. In the wild, however, the shallow water-dwelling creatures are almost never seen.
In the wild, they’re known to prey on small fish or invertebrates and scavenge dead things. “I don’t see them as being overly picky," Sheehy said. "In the pet trade people seem to be able to feed them all kinds of things.”
They’re decidedly odd creatures. Often mistakenly called "rubber eels," even the normally reserved University of Florida publicity apparatus described them as “weird, noodle-shaped amphibians.” Though they possess lungs, they also breathe through their slick, elephant-colored skin and give birth to live babies instead of laying eggs. In some Caecilian varieties, mothers feed their young with the slimy secretions coating their bodies, says Sheehy. The babies “are scraping off the mucus and eating that,” he said.
As wild things go, they're visually impaired (Caecilians means “blind ones”) but a pair of sensory tentacles between their eyes and nostrils may help them find food.
Caecilian scientists are an even rarer breed, Sheehy says. “The number of researchers even working on them is exceedingly small.”
That’s because Caecilians are “absolutely the least known of the major amphibian groups,” he said. “They’re typically really difficult to access because they’re really difficult to find … It’s kind of like a joke among biologists: Ceacilians aren’t something you can go out looking for – you find them when you find them.”
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Renowned Florida herpetologist Chris Lechowicz, who’s been tromping around wild Southwest Florida for nearly two decades as the Sanibel-Captiva Conservation Foundation’s wildlife and habitat management program director, hasn’t come across one in the wild.
Even Sheehy, who’s searched for them in many parts of the world, has never found one. “You just don’t,” he said. “Most of them live their whole lives hidden (so) you can’t base a career studying things that you can’t find.”
All of which makes it hard to know whether they’ll be fruitful and multiply in south Florida and if so, if they’ll become a problem the way Burmese pythons have become in the Everglades, where their voracity has put a serious dent in wildlife populations.
“Almost nothing is known about Caecilians in their natural habitat,” Sheehy said, let alone whether south Florida would be hospitable. But he has gotten credible reports of others, which is why he’s mounting an investigation.
“I’m going down to South Florida in the next couple of weeks to investigate and confirm and see if I can find more and if I do, where are they, and how widespread are they?”
The specimen came from about a mile south of the Miami airport, but Sheehy says they’ve been spotted in other parts of the canal “far from where this initial specimen came from.” From its Miami beginnings, the Tamiami Trail stretches to Tampa through Collier and Lee counties. Along most of its southern length is the freshwater canal created a century ago as humans dredged out soil and limestone for the elevated roadbed.
“At this point, we really don’t know enough to say whether caecilians are established in the C-4 Canal,” Sheehy said. “That’s what we want to find out: what the impacts might be of an invasive species in our native waters. We need to know that and know how they’re impacting the environment.”
If they are here, he points out, the news might not be all bad. “It could be anything between a negative impact, to neutral, where they’re really not doing much either harmful or beneficial, or it could be beneficial. They could not really be doing a whole lot to harm anything, but maybe they’re a great food source for something else ... Positive impacts sometimes happens with introduced species,” like European honeybees and earthworms, which have become critically important to food production."
Bottom line: “We need to know what it is so we can get ahead of it and mitigate any issues."