SAN ANTONIO – Swamp rats are having a moment.
After a story about their invasion of a Texas park went viral, KSAT reached out to the San Antonio River Authority (SARA) and learned that the orange-toothed rodents live here, too.
Nutria, also known as swamp rats or coypu, have been trapped along the Mission Reach segment of the River Walk including the low water crossing at Padre Park, near the VFW and also close to Lonestar Blvd.
“Mission County park and around Padre Park are areas that nutria have been spotted,” said SARA Watershed and Park Operations Manager Kristen Hansen.
Nutria are semi-aquatic, herbivorous rodents that eat 2 1/2 - 3 1/2 pounds of vegetation along the banks of the San Antonio river every day which causes the banks to erode over time. They also dig their burrows into the sides of the banks.
They are similar in size to beavers, but nutria have long, round, scaly tails with bristles, unlike the beaver’s broad flat tail.
They breed up to two times per year with up to 9 offspring per litter, according to Hansen, which causes the nutria population to increase “at an alarming rate.”
“They arrived in North America in the 1930′s as a fur-bearing species and since then, they have spread to cover the eastern two-thirds of Texas as well as many other states,” Hansen said.
To control the invasive species, SARA hires specialists to place traps off the trails along the banks of the San Antonio River to catch the nutria. Once they’re trapped, the nutria are “euthanized in accordance with Texas Parks & Wildlife Department.”
So far this year fewer than 10 swamp rats have been trapped in the San Antonio River.
The number of swamp rats trapped in past years:
- 2019 - 10 nutria
- 2018 - 60 nutria
- 2017 - 32 nutria
If you see a nutria along the San Antonio River you can report the sighting to the San Antonio River Authority at (866) 345-7272 or on the SARA website sariverauthority.org/contact-us-0.
“As the agency responsible for the maintenance of the Mission Reach segment, it’s important that we address any challenges to the well-being of the project for the safety and enjoyment of the general public,” said Hansen. “Our staff worked to find an appropriate solution to the damage caused by the Nutria-rat population in an effort to preserve the project’s ecosystem and the health of the San Antonio River.”