The nutria is, as you may already have guessed, a rodent. It has adapted to life in the water–in fact, its nipples, rather than being on its stomach, are on its flanks so that babies can ride around on momma’s back and nurse without drowning. They are originally from South America, and were introduced in the States for their fur. They are now considered a pest species in this part of the world, and you can receive money for handing in a nutria carcass, which makes me sad but which I also understand. The reason why is that they can be very detrimental to wetlands, which are a famously fragile ecosystem already imperiled by human development.
Many people who pass them by exclaim over them thinking that they are beavers, despite signs on the trails around the stream explaining their name and origin. While they do look rather beaverish, they have long, thin tails like rats, and do not build dams of any kind. Rather, they appear to dwell in holes up under the bank, hidden away from predators, but whether they dig them themselves, possibly expanding on bank swallows’ excavations, I don’t know. They have also been mistaken for otters, but unlike the fish-loving otter, nutria exist solely on greenery. They love being thrown things like lettuce (though only romaine or iceberg–bitter spring greens are shunned by them!), bits of fruit, and bread. Some are fairly fearless, and if you have food, they will come right up to you and may even take it from you with their little hands. I have more than once been startled by feeling a wet little paw on my foot when I didn’t realize a nutria had approached me, hoping to get closer to the food I was holding. They have bright orange teeth, again rather like a beaver’s, which are rather alarming, but I have never seen a nutria behave aggressively. It’s as well to still steer clear of their mouths, though.