Invasive 8-inch-long African snail reappears in Florida

 

Giant invasive snail, Achatina fulica. Photo courtesy of USDA.

I wrote a post a couple of weeks ago about Burmese pythons and other giant constrictors now living wild in Florida. Thousands of them are successfully breeding there. I got a lot of pingbacks from that post, mostly from indignant owners of giant constrictors.

As you probably know, introduced and invasive plants and animals are everywhere in the U.S. In one county park near my home in North Carolina, 35% of the plant species are nonnative - so I'm told by a professional botanist who frequents the park.

Florida is vulnerable
Florida is particularly susceptible to invasion by nonnative species because of its subtropical climate, and because of the number of people and shipments coming in from the Caribbean and Latin America. One invader that has been in the news lately, as a major plant pest and potential public health threat, is the giant African snail Achatina fulica. Its maximum size is 8 inches long and 4.5 inches wide - one of the world's largest land snails. One pair of mated adults can lay 1,200 eggs per year.

A child brought 3 of the snails into the Miami area as pets in 1966 and his grandmother subsequently released them into her garden. By 1973, those three had spawned a population of 18,000 snails. The government spent $1 million over the next decade trying to get rid of them.


They eat citrus crops, can carry human disease
Mark Fagan, a spokesman for Florida Dept of Agriculture and Consumer Services says the main concern is damage to agricultural crops. The snails can eat at least 500 types of plants, including citrus crops. They are known to carry a parasite, rat lungworm, that can cause serious diseases such as meningitis in humans. According to the University of Georgia website, these diseases can be transferred to humans by eating raw, undercooked infected snail meat or contaminated vegetables. Vegetables can become contaminated if the snails move across them.

The snails also eat stucco and plaster for minerals to grow their shells, damaging homes and other buildings.

Snails found in Hialeah, Florida

These giant African snails were thought to be eradicated in Florida, although present on Caribbean islands. But they have recently resurfaced in Florida, says Fagan. Multiple snails were found last month in Hialeah, Florida.

In addition to their large size, the snails can be recognized by having 7 to 9 spirals and a brownish shell that covers half the body. If you see these snails in your area, call your local department of agriculture.

Sources:

Anthony Colarossi. "Florida targets giant African snails." Orlando Sentinel. Colarossi's article appeared in the Charlotte Observer March 22, 2010.

University of Georgia College of Agricultural and Environmental Sciences

Key words: invasive species invasive snails Achatina fulica African snail Florida public health menace agricultural pest

10,000 pythons breeding in Florida, says new USGS report

This post now on Google News!

Nine species of introduced giant snakes could pose risks to U.S. ecosystems, according to a report recently released by the U.S. Geological Survey. The giant species now present in the U.S. are descended from imported pets that have been released outdoors.  Already there are more than 10,000 Burmese pythons reproducing in the wild in south Florida.  Boa constrictors are also known to be reproducing in south Florida. The USGS says there's "strong evidence" that an African python may have a breeding population in Florida too.

Some snakes big enough to eat people
All nine potentially risky species are constrictors - nonpoisonous species that kill their prey by wrapping around them and squeezing until the prey can't breathe.  The USGS report says that "most...would not be large enough to consider a person as suitable prey."  But some of then are large enough to eat people, such as the reticulated python, which can grow longer than 26 feet.  This python is the snake "most associated with unprovoked human fatalities in the wild."  Reticulated pythons have been both sighted and captured in south Florida, but are not yet known to be breeding there.

Mature individuals of other species - Burmese python, northern and southern African pythons - have also been documented killing people in their native range, although unprovoked attacks are rare.

Invasive giant snakes threaten more states than Florida
Several species of giant snakes are considered more "high-risk species" for the U.S.than others because they
(1) tolerate cooler temps and could put larger areas of the U.S. mainland at risk - not just Florida
(2) are a major threat to native mammals and birds
(3) are common in the pet trade, hence likely to be released within the U.S.

Among these "high risk" species are the boa constrictors and yellow anacondas, which could breed north of Florida in areas with mild winters.  

Above, a boa constrictor in Manuel Antonio Parque Nacional in Costa Rica.  Photo by Sally Kneidel, PhD

Above, our friend Jose Luis holding up an immature boa on his farm near Limon, Costa Rica.  

Photo by Sally Kneidel, PhD

Nicole the resident biologist, Ken Kneidel and Sadie Kneidel examine an immature boa at Palo Verde Biological Station of OTS, in Costa Rica.  Photo by Sally Kneidel, PhD

Several species of anacondas have also been sighted or captured in south Florida. Anacondas can grow longer than 25 or 26 feet too, and I believe have been known to kill humans, although the USGS report didn't say that.  I've read that the record length on an anaconda is 28 feet.

Deep in the jungle, we found a beheaded anaconda 
Below are two anaconda pictures my son Alan took on a foray into the Amazon rainforest in 2008. We were slopping and tripping through a difficult swamp in an effort to spot hoatzins (birds) when we passed a family of indigenous Peruvians heading back toward the river, returning from a hunting/foraging trip. All of them, including grandma, were slogging barefoot through the most treacherous swamp I've ever experienced, having submerged 3" long thorns. (I stepped on two of those thorns; they went right through my rubber boots.) But the Peruvian family seemed unperturbed. The whole family had homemade packs on their backs, and one pack carried a chopped up anaconda they intended to eat. The head, as you see, they had left behind.

The head of an Amazonian anaconda, severed by an indigenous family hunting for food. Photos by Alan Kneidel.

Introduced snakes can devastate native wildlife
The USGS scientists who wrote the new report said that U.S. birds, mammals, and reptiles in areas of potential invasion have never been exposed to huge snakes before, snakes longer than 20 feet and weighing more than 200 pounds.  Said Dr. Gordon Rodda, a USGS scientist, "Compounding the risk to native species and ecosystems is that these snakes mature early, produce large numbers of offspring, travel long distances, and have broad diets that allow them to eat most native birds and mammals."  He also said that most of these snakes can live in a variety of habitats, including urban or suburban areas. Boa constrictors and northern African pythons are already thriving in metropolitan Miami.

"We have a cautionary tale with the American island of Guam and the brown treesnake," said Robert Reed, an invasive-species scientist with the USGS, and coauthor of the report.  "Within 40 years of its arrival, this invasive snake has decimated the island's native wildlife -10 of Guam's 12 native forest birds, one of its two bat species, and about half of its native lizards are gone."  Reed goes on to say that "these giant snakes threaten to destabilize some of our most precious ecosystems and parks, primarily through predation on vulnerable native species."

What can you do?
Don't keep snakes as pets, and if you must do so, don't get snakes that grow into large constrictors. If you have one, or know someone who does, there are alternatives to letting them go outdoors after they grow too large to keep at home. Google "reptile sanctuary" to find a facility near you that accepts unwanted pets. If googling doesn't help, call a nature center or zoo near you for referral to a nearby sanctuary for unwanted pets. Releasing non-native pets outdoors is never a good idea.

More snake pics by Sally, below

A coiled and wary Bushmaster, among the most venomous vipers in Latin America. Photo taken along a trail at La Selva Biological Station by Sally Kneidel, PhD

 

A coral snake at Arenal Volcano Parque Nacional in Costa Rica, photo by Sally Kneidel, PhD.

Sources:

Catherine Pucket (USGS) et al.  10/13/2010."Report documents the risks of giant invasive snakes in the U.S."  USGS Release. USGS: science for a changing world.

Paul Rauber. Jan/Feb 2010. "Woe is us: ready, set, panic. Snakes on plains." Sierra magazine.

Some of my previous posts on the pet trade, invasive species, and snakes:

Why do girls fear snakes and spiders more?

Lawn is a dirty word.

Housecats are invasive species. 

Housecats kill hundreds of millions of species annually

How to convert a lawn to a lawn to a native meadow or woodland

Lawns are 5th largest "crop" in terms of lawn use 

Monkeys and parrots pouring from the jungle

Keywords: invasive species snakes threats to wildlife wildlife trade endangered ecosystems python anaconda, boa constrictor python predation by housecats predation on birds

5 Ways to Help Birds and Wildlife Survive Drought and Dry Weather

1. Provide fresh water daily. The safest way to offer water to birds is in a bird bath that's elevated beyond the reach of house cats. Change the water every day to avoid spreading disease.

2. If you don't have a bird bath, put a bowl on the ground - but only if you can put in an open area where cats cannot ambush birds. I'm guessing that a cat can ambush a bird from any sort of hiding place within 10 feet of the water bowl. Maybe more than that. If you have natural areas in your yard, squirt them occasionally with the hose. Squirrels and rabbits and chipmunks will come to a bowl on the ground, but snakes, toads, mice etc, that are burrowed in the leaf litter need moisture too. And they generally won't come to a bowl to drink.

3. Offer seeds and fruits to birds, such as slices of orange. Drought affects not only the water available, but it affects the insects and plants that birds and animals eat. As above, make sure the feeder is not a bird-trap for the local house cat, by elevating it or placing it on the ground with a wide circumference of open area. Keep it clean by scrubbing it regularly.

4. For the long term, native plants withstand drought much better than introduced plants and ornamentals, many of which are from tropical rainforests. So landscape your own yard with native plants, which can be found at plant nurseries, even Home Depot (ask the plant manager there). If not, google Native Plant Society and your state name to find a local source for native plants. Don't dig up native plants in protected woodlands for your own yard - tempting but damaging to wildlife. You might find a friend who propagates native plants and will give you a few seedlings or seeds. For a good guide to landscaping with native trees, shrubs and perennials in North Carolina, see www.ncwildflower.org. Most states have such organizations now. Some of the most attractive native plants for landscaping in North Carolina are eastern redbud trees, purple coneflower, black-eyed Susans and eastern columbine. Animals love shrubs and trees that produce berries and fruits, such as mulberry, dogwood, and persimmon. Ask at your local native plant society or nursery about which varieties are native to your area.

5. Keep your house cat indoors. Birds and small animals weakened by hunger and thirst may be more vulnerable than ever to house cats, all of which prey on birds or small mammals - whether you witness it or not. Not only will the birds and other animals be better off, but your house cat will be safer too. For more info on how to make your cat a happy indoor cat, local cat laws, and resources, visit www.abcbirds.org/cats.

Key words::5 top ways to help birds, wildlife and dry weather, effect of drought on animals, house cats, housecats and predation, 5 top ways to help birds, wildlife and dry weather, effect of drought on animals, house cats, housecats and predation, keep cats indoors, small mammals