We’ve all heard of them, seen them, tried to eradicate them, or found cool ways to eat them. Whether we like it or not, invasive species have taken over our lands and our waters. But there are some repeat offenders that everyone seems to know about: we’re looking at you, wild pigs, garlic mustard, and zebra mussels.
However, there are other species that are not as common but are just as problematic and definitely rarer than these main species. From the shores of New England to the rivers of California, here are three of the strangest invasive species you’ve probably never heard of.
african clawed frog
The African Clawed Frog is an invasive amphibian that disrupts ecosystems and affects native fish populations such as trout and salmon. According to Max Lambert, a research scientist with the Washington Department of Fish and Wildlife, these chubby-bellied frogs with black-clawed hind legs have a voracious appetite, eating large numbers of fry, tadpoles and native insects. The presence of African Clawed Frogs in a water system can quickly decimate native populations because they consume a large amount of the food source.
As carriers of disease, they have the potential to introduce harmful pathogens that also harm native amphibian and fish populations. Humans should be careful when handling African Clawed Frogs and wash their hands thoroughly after contact. The mere presence of African Clawed Frogs requires the waters to be quarantined (due to the diseases they carry), limiting recreational fishing potential.
African Clawed Frogs have a distinctive appearance from most native frogs. They have olive to brown mottled skin with no eyelids, tongues, or vocal sacs. The forefeet are unwebbed, while the hind feet are fully webbed and have sharp, black claws. They often grow to be larger than the average adult’s fist. African clawed tadpoles look like small catfish, with a pair of long barbels extending from each side of the barbel.
Many states have reported African clawed frog infestations, but populations are highest in Washington, California, and Florida.
Chinese mitten crabs
Through the Chesapeake Bay Program.
Chinese crabs are such a troublesome invader that they have earned a place in the top 100 invasive species on the global list. They have now made their way into waterways and coastlines across the country.
Crabs originate from China, where they are considered a seasonal delicacy, but are banned in the United States. They are destructive to many species in many ways. They have a voracious appetite and prey on local wildlife, threatening not only fish populations but also food sources for game animals that consume those fish.
The problem crabs have already spread to several California waterways, the Connecticut coast, the Chesapeake and Delaware Bays and the Hudson River, according to the Smithsonian Environmental Research Center. They spread rapidly and can migrate up to 11 miles daily over land and water. That’s a frighteningly long distance for something so small.
Chinese mitten crabs are easily identifiable due to the distinctive fur that covers their front claws. It looks like they are wearing fingerless gloves. Other identifiable features include a notch between the eyes with four spines on each side of the notch. Anyone who finds one should take close-up photos, freeze it or preserve it in alcohol (yes, seriously), and report it to the Smithsonian Environmental Research Center here.
Asian jumping worms
Through the Wisconsin Department of Natural Resources.
These quirky jumping worms, also called crazy worms, snake worms, and Alabama jumpers, originated in Asia. While they can be entertaining to discover, as they wriggle and launch themselves into the air, they are a major threat to forest habitats. They alter the quality of the soil near the surface by consuming the rich organic top layer and leaving behind a distinctive grainy soil filled with nutrient-deficient worm castings. The molds change the physical structure of the soil, making it more like coffee grounds or boiled hamburger meat, according to Colgate University biology professor Tim McCay, who has been involved in identifying the invasive worms in New State. York for the last three years.
The destruction caused by jumping worms makes the previously ideal forest floor soil inhospitable to some plants and animals, leading to soil erosion and reduced food sources for wildlife , such as white-tailed deer, rabbits, and others.
Jumping worms have a distinctive appearance from other varieties of common worms. The clitellum (or collar) of a jumping worm is smooth, milky white, and located about a third of the length of the worm’s body from the head, if you can figure out which end it is.
Because they are asexual and mature in just 60 days, jumping worms reproduce quickly and easily. The first hatch is usually in late June or early July, with populations doubling from September to the first hard frost. iMapInvasives data indicates recorded sightings of these worms in the Midwest and Northeast. If you want the heebie-jeebies, check out this video from the Wisconsin Department of Natural Resources.
Accurately identifying invasive species is key to controlling their spread. Be on the lookout for these rare critters while recreating outdoors, and if you see them, consider sharing your location on a resource like iMapInvasives to protect natural flora and fauna.