NUTRIAS ARE BIG RODENTS

by Whit Gibbons

March 26, 2017

Last week, while I was returning the stare of a giant rodent 20 feet away, my flashlight beam strayed into a pool of water 50 feet farther into the swamp, revealing a pair of shining red eyes. The giant rodent was a nutria. The red eyes belonged to an American alligator.

Both were exciting to see. Yet another surge of adrenaline came as someone pointed out an enormous spider sprawled near my hand on the railing of the boardwalk. Its outstretched arms were at least 5 inches from front to back. I was rounding out my time at Southeastern Louisiana University with a nighttime ecology field trip – a fitting end to my visit.

I had gone to see the graduate students in the biology department and, after an extended crawfish boil that stretched into the evening, someone suggested a trip to a nearby swamp to see what we could find. One student gave me a flashlight; another slapped a snake stick into my other hand. Two more carried dip nets.

Turning down the opportunity to venture out with half a dozen knowledgeable tour guides was out of the question. We went forth into the spooky swamp, listening and identifying calling frogs along the way.

In an earlier daytime field trip, we had found several cottonmouths, watersnakes and black racers in a state park. We also added a copperhead to the list of snakes known from that area. I was pleased to see the enthusiasm displayed by the ecologically minded students bent on enjoying the first days of spring the way they should be enjoyed: outdoors investigating nature.

Although most of the students were herpetologists interested in reptiles and amphibians, enjoying the other wildlife that can turn up in a swamp was not only acceptable, it was encouraged. We spent time watching the nutria chomp on some vegetation until it decided we were worth keeping an eye on and finally left.

Nutria, also called coypu or river rats, are one of the largest rodents in America. Big ones, which indisputably look like the giant rats they are, can weigh over 20 pounds. They have hairless round tails, whereas beavers, which hold the record for the biggest U.S. rodents, can be distinguished by their flat tails. Muskrats, which can live in the same habitats as nutria, have vertically flat tails and get nowhere near as large.

I was glad we got to see a nutria simply because they are impressive beasts. However, they are an invasive species imported originally from South America and are not welcome guests in Louisiana and other states where they have become established.

Despite bounties and other programs to eradicate nutria, they are still abundant and are perceived as a big nuisance because they eat native vegetation. Nutria have spread into the southern marsh areas of Alabama, Mississippi and Texas but are unlikely to expand permanently into more northern areas as they are restricted to warmer climes in their native habitats.

As for the spider, it was one of the large, very large, fishing spiders that prey on aquatic insects and small fish. Fortunately, my hand did not look like a fish or an insect. We were rewarded with amphibian wildlife in the form of both sirens and amphiumas, the latter being the longest salamander species in the Western Hemisphere. We had seen a captive one earlier in the day that was more than 4 feet long and as big around as a softball.

I’m not sure a nighttime visit to the swamp is the best way for budding naturalists to start appreciating nature in its springtime glory, but at this time of year, you need to be outside somewhere doing something. Even your own neighborhood is likely to reveal sights and sounds you have not experienced before.

This is the time of year everyone can appreciate the natural world around us that we do not want to lose – although the nutria are invited to return to their native lands.

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