I didn’t realize I was photographing such a destructive weapon when I took pictures of the nutria (alias coypu, ragondin, river rat, beaver-rat, or little beaver) last week at the Audubon Zoo in New Orleans.
The Coypu are unique: they are the only member of their taxonomic family (that in itself is unusual); they grow and reproduce really fast — can reach sexual maturity in 3-4 months and females can produce as many as 3 litters a year, with each litter having as many as a dozen offspring; they have an astonishingly short lifespan (well, with all that reproducing, they must get worn out!) of less than 6 years, with only 15% of the population alive after just 3 years.
Their destructive potential lies in their wasteful habit of leaving 90% of the vegetation they cut down. They eat only the base of above ground stems, dig through the soil for roots and rhizomes of other plants, and generate large disturbed areas of fallen and uprooted vegetation. Obviously not good for native plants, and particularly for areas where soil disturbance leads to massive erosion, like the wetlands of Louisiana.
Biologists have estimated that Louisiana wetlands affected by nutria damage decreased from 80,000+ acres in 2002-03 to less than 7,000 acres in 2010-11 (nutria were just one of the causes of the loss of wetlands here). These are the same wetlands that protect New Orleans and that part of the Gulf coast from hurricane damage. Similar habitat loss has been observed wherever nutria have been introduced (e.g., 7-8,000 acres in Chesapeake Bay after nutria were introduced in the 1940s).
Nutria were introduced all over the world (except Australia) as a source of meat and fur, but their populations grew so fast, eradication programs are rapidly being established now. In addition to their environmental impact, they are also a host for a nematode (roundworm) parasite that can infect humans who wade in nutria-infested waters causing a dermatitis called “nutria itch“. So don’t go swimming in the bayou.