Rodents of Unusual Size

One critter that we see fairly often on our bike rides is the nutria, or coypu (Myocastor coypus). They seem to be everywhere in the canals and in the Ashida River that flows through the city. As you can see from this shot of one I took this weekend, they are a semi-aquatic rodent are about the same size as a beaver but with a long, rat-like tail.

I am surprised this one let me get so close

Originally from South America, they have been introduced to every continent except for Antarctica and Australia for their fur. Nutria were introduced to Japan in 1910 and the military promoted small fur farms to raise nutria. When the price of the pelts dropped, many nutria were released into the wild where they happily procreated, due to a lack of natural predators and lots of prime habitat. Since 1963, nutria have been hunted in Japan to control their ballooning population. When looking for population counts in Japan, I discovered that Okayama has the highest number of nutria in the country. It is about 9.5 kilometers from our apartment to the border of Okayama Prefecture, so it makes sense that I see them so often.

Super cute baby nutria

The foraging and nesting habits of the nutria have an incredibly detrimental effect on the health of wetlands and water systems in the countries in which they are introduced. They destroy nesting habitat for native species and cause massive soil erosion by eating marsh plants and burrowing through root systems. Places like Louisiana (are you surprised?) have created a 5$ bounty for every nutria shot in an attempt to decrease their population. Some countries are even trying to popularize the sale of nutria meat for human consumption. The meat has euphemistically been named "ragondin", the French word for nutria, and has been found to be much leaner, higher in protein, and lower in harmful microorganisms compared with farmed conventional meats. If you ever manage to get your hands on some ragondin, there are lots of recipes out there that will help you make the most of it.

Shooting them for fur, meat, or even a 5$ bounty may seem cruel, but in many of the countries to which they have been introduced, humans are the only predator able to lower their populations. The wetlands they are destroying are incredibly complex and fragile habitats which play a critical role in maintaining water quality and species richness. In many countries, hunting, whether done by individuals or the government, is one of the few viable options for controlling their population. I say, if you are going to shoot it anyway, why let it go to waste?