Mammals - invasive

Nutria (Myocastor coypus) on May 17, 2008

Submitter does not have a specimen

Description of specimen

I spotted the animal while it was swimming away from me. I first thought it was an otter or beaver but then it dove and I could see a long skinny rat-like tail. I did not know what it was but a friend suggested a nutria, and after looking at pictures of them online, I've concluded that a nutria is what it likely was. I've walked through the park from Knapp street to the Bybee/Hwy 99 ramp intersection most weekday mornings for four years and have never seen any mammals such as this.


Thank you for submitting this report. The animal you saw was in fact a nutria; the rat-like tail is one of the distinguishing characteristics of this species. Nutria are now common in wetlands throughout the Portland Metro area, so you may see more nutria in the future.

If you would like more information on nutria, please visit the nutria page on the Center for Lakes and Reservoirs website at My contact information can also be found on this page if you have further questions.

Trevor Sheffels
Center for Lakes and Reservoirs
Portland State University

Trevor Sheffels
May 22, 2008, 4:47 a.m.