Why hello there! It’s a pleasure to meet you! My name is Ollie, and I am one of the San Antonio River Authority’s Mejores amigas de Basin! I work together with my friends Heronimo the Great Blue Heron and Rex the Common Raccoon to make the San Antonio River Basin a fun place to play and explore. I am an expert in everything recreational: hiking, fishing, kayaking, swimming, community events, you name it. But there is one more thing I am an expert on, and that is the Nutria de río norteamericana (Lontra canadensis). After all, I am one!
Join me as we explore the crucial role the North American River Otter plays in Texas rivers, how to spot our invasive doppelgänger, and what you can do to help.
this South Texas native is a sleek, playful mammal found throughout the waterways of North America, from Alaska to the Gulf of Mexico. With its streamlined body, dense fur, and muscular tail, the river otter is well-adapted for swimming, using its webbed feet to chase fish, crayfish, and frogs. Known for their social and curious nature, river otters often engage in playful behaviors, like sliding down muddy banks. De acuerdo a mammal biologists, otters play a crucial role in su ecosistemas as an indicator especies, a species whose presence, absence, or abundance in an environment serves as a sign of the overall health or condition of that ecosystem. They are also a keystone species, controlling prey populations and enhancing biodiversity. In other words, healthy otter populations are a great sign an ecosystem is thriving, which is exactly why we otter care about them!
Where are they found in Texas?
River otters, known for their playful behavior and agility in water, are a common sight in East Texas’s lakes and streams. However, their historical range in Texas was much more extensive. These semiaquatic mammals once inhabited areas stretching from the eastern Panhandle, through the central Edwards Plateau, and down to the Rio Grande Valley in South Texas—including the Cuenca del río San Antonio.
According to Craig Hensley, a biologist with the Texas Parks and Wildlife Department (TPWD), river otters were historically found in Bexar County down through the Goliad area. Extensive hunting and trapping during the early American fur trade, as well as water pollution and habitat loss, led to declines in otter populations in the late 19th y principios de los 20th centuries, completely eradicating them from certain areas. However, because of a reduction in hunting, improved water quality, and habitat restoration, river otters have been documented expandiéndose hacia el oeste a sus hábitats nativos as far as the Abilene area. Because of this expansion, they were removed from TPWD’s Especies de mayor necesidad de conservación list in 2021.
In an exciting chapter in the river otter’s conservation story, Texas State University announced in Spring 2024 that there had been four sightings of the river otter in the San Marcos River. This was the first time in 70 years that they had been documented in that area. Otters may be moving back into the San Antonio River Watershed as well. In 2024, a river otter was visto en el río San Antonio en Goliad by Goliad State Park Superintendent Jared Ramirez. In 2025, River Authority staff caught on otter on a trail camera in Bexar County, and this past summer staff spotted them in Cibolo Creek!
Check out the picture below: can you spot the otter?
“I would encourage people to keep their eyes open for them in the San Antonio area over the next few years and report sightings to iNaturalist.” said Hensley. However, glimpsing one is challenging because of their elusive and shy nature. Where have the most recent sightings in our area been? Check out the iNaturalist website for información sobre avistamientos recientes de nutrias de río en Texas.
Nutria: An Invasive Look-Alike
As you’re keeping an eye out for river otters, it’s important to know more about an invasive species they can often be mistaken for—la nutria (coipus miocastor). The nutria, also known as the coypu in some countries, is an invasive rodent native to South America. According to the River Authority’s Watershed and Park Operations Manager Tommy Mitchell, nutria have been found along the Mission Reach, Eagleland, and King William areas of the river. “The primary concern with nutria is the impact they have on aquatic vegetation and the riverbank from burrowing, which causes the area to fail and erode the channel. We have a program in place for trapping and removal of nutria similar to the feral hog program. The amount of nutria seen seems to have declined over the years, we hope because of the removal program.”
Originally brought to the United States starting in 1899 to be grown and harvested for the fur trade, many nutria breeders released them in the 1940s when the fur trade bottomed out and others simply escaped captivity. Due to a high reproductive rate when left to their own devices, nutria quickly became abundant throughout the Gulf states and up the west coast. Nutria are occasionally misidentified as river otters; however, the two are in different taxonomic orders. As members of Order Carnivora, otters are related to badgers, minks, weasels, and wolverines, all members of the Mustelidae family. Nutria are rodents and closely related to beavers and muskrats. Nutria are found throughout Texas, including the San Antonio River.
How You Can Help River Otters
Can you imagine seeing river otters in the upper San Antonio River in the future? Here are some steps to take to make sure we keep our local waterways and aquatic habitats otter-friendly.
- Keep Wildlife Wild! While it might be exciting to see an otter in the wild, it is important to remember to keep wildlife wild. Never approach, feed, or touch wild animals—this keeps both you and the animal safe!
- Don’t let litter trash your river. Otters feed on fish, so it is important to ensure the fish lives in waterways free of harmful chemicals and heavy metals to avoid the species getting mercury poisoning.
- Leash your dog. Otters prefer to sleep in bushes and tall grasses near waterways, so make sure fido is leashed so they don’t attack or distress a sleeping otter.
- Use existing river-access points. This helps to preserve otter habitat from human impact and prevent erosion.
Thank you so much for spending some time learning about the otters of the San Antonio River Basin! I hope you learned something useful through this blog and that you use that knowledge to make our rivers a safer and cleaner habitat for all the animals that call them home.
Stay otterly amazing!
Sincerely, Ollie
Autor: Emily Rew, Education Coordinator
Emily Rew is an Education Coordinator at the San Antonio River Authority, dedicated to connecting people with the science, stewardship, and stories of the San Antonio River. As Chief Editor of the River Authority blog, she works with scientists, engineers, and partner agencies to bring the watershed’s fascinating wildlife, projects, and conservation efforts to life. When she’s not writing or developing educational programs, you can find her exploring Texas’ waterways by kayak, bike, or trail with her husband and dog, Ember.
Thank you to the experts at Texas Parks & Wildlife Texas Nature Trackers for assisting with this feature!
