365 Urban Species. #117: Muskrat

[urbpan]

Photos by cottonmanifesto

Urban species #117: Muskrat Ondatra zibethicus

More than once, an excited friend has reported seeing a beaver or an otter in a waterway in the city. "Really?" I ask, "how big was it?" With their hands they indicate the size of a rabbit--too small to be either. Those animals have habitat requirements that generally preclude them from being thought of as urban species. The muskrat, on the other hand, is a common resident of many cities across North America. Despite its name, the muskrat is more properly called a water vole than any kind of rat. It has a blunt face and long vertically flattened tail for swimming, and on land has a rounder appearance than a rat.

Muskrats are tolerant of fairly polluted water, and need only a muddy bank or even a culvert to build a den in. In an area with adequate aquatic plants they will build a den of vegetation. They feed mostly on plant life, but like most rodents, are somewhat omnivorous, taking mollusks and crustaceans. Urban muskrats are preyed upon by red-tailed hawks, and can drown in their burrows during flooding rains. Their fur was an important part of the North American economy in past years. These days I find they have great value in sparking interest in urban nature.

This time of year they feed on large amounts of maple and oak flowers that fall into the water and onto the riverbanks.

A very similar-looking, but much larger aquatic rodent has been introduced to the Gulf States, and the Pacific Northwest. The nutria, Myocastor coypus, from South America to the United States, and many other countries around the world, to boost fur industries, is about five times as massive as the muskrat. They can be distinguished by their tail, which is round in cross-section, as well as their size: averaging about ten pounds as compared to the less than two pound muskrat. Nutria are urban fixtures in cities like New Orleans, and major ecological problems wherever they are introduced, considered one of the 100 worst invasive species in the world.

Comments

[badnoodles.livejournal.com]

Might want to put the text before the LJ-cut for those of us who don't always click to see cottonmanifesto's lovely pictures. :)

I've never been fortunate enough to live in an area with appreciable mammalian aquatic life - Texas has too many water moccasins, and California doesn't appear to have running water.

[bunrab.livejournal.com]

Texas has nutria - Lake Austin and Lake Travis have so many nutria that the water moccasins don't really make a dent in them. The power of rodents!

[badnoodles.livejournal.com]

Really? Interesting. I'm a Houstonian, so I never got out to Lake Austin or Lake Travis - most of my aquatic forays were into the creek bottoms of East Texas or safely ensconced on a fishing boat on lake Conroe or Brownwood. :)

[bunrab.livejournal.com]

I dunno about Lake Conroe, but nutria are in all the lakes that are along the Lower Colorado River, as far as I know, including all the way east to at least Katy.

[urbpan.livejournal.com]

Thanks, posting too late at night has its drawbacks :)

I can't imagine that a water mocassin would much threaten a nutria (or otter or beaver for that matter) but it could probably take a muskrat.

[bunrab.livejournal.com]

Quibble: the muskrat is a nutria, not a vole. Originally native to South America, but now widespread over much of North America, and a downright problem in the southern US; in cities like Austin, and anywhere along the gulf coast, especially Louisiana, muskrats/nutria are great despoilers of trees, gardens, yards, etc. (Nutria live all over Town Lake, the lake/river impound which the Bat Bridge goes over. So of course, I have gotten to know more about nutria than any sane person wants to know. Also, since they are related to my beloved guinea pigs, I wind up knowing a bit more...)

[urbpan.livejournal.com]

Mistaken identity! I did want to add clarifying comments about nutria, but I forgot due to the late hour of posting. Thanks for waking me up. New paragraph makes the distinction.

[bunrab.livejournal.com]

Thanks! Should I erase my comment? I was posting late at night, too (that 11:41 timestamp is not accurate; I've never figured out why my selection of time zone has always produced the wrong time), and in daylight I am afraid it sounded like harsh criticism, which is NOT what I intended. I know that you know way more about these critters than I do.

Is that Susie or Sam?

[brush-rat.livejournal.com]

Did whirl and twirl and tango while Singin' and jinglin' a jangle? Did it float like the heavens above?

So, they aren't even proper rats? How disappointing.

[ninthraven.livejournal.com]

cottonmanifesto takes really great nature photos. I am always amazed how she captures the details so clearly.

[cottonmanifesto.livejournal.com]

I blushed when I read that. Thank you so much!

[bunrab.livejournal.com]

When my mom first moved to Austin, in the early 90's, she called me up excitedly a few days after she moved into the apartment I had found her, which was near a creek, to report that she had seen an otter, and enjoyed watching it frolic. She was heartbroken when I told her she had seen a rodent, not an otter, and all my descriptions of how fascinating the whole ecology of nutria were, and how they fit into the general picture of South American rodents, from cavies to capybaras, did not console her. People have that reaction to rodents. If something is a rodent it's somehow no longer cute. Sheesh. Anyway, that's why your paragraph about people reporting otters immediately brought nutria to mind - 'cause that's what people think they're seeing in Austin.

[bunrab.livejournal.com]

P.S. The worst part about nutria in Austin is that they are NOT escapees from fur farms; they were deliberately brought to Austin to live in the lakes because someone thought they'd help control the massive duckweed problem that most of Austin's lakes have, by eating the stuff. Of course, it didn't work that way, and Austin now has a massive duckweed problem AND a nutria problem.

[maybethecat.livejournal.com]

we just opened up an invasive species exib, but it is small and only have some animals destroying our environment like some zebra mussels and red eared sliders and some fish

[miwasatoshi.livejournal.com]

I finally saw my first muskrat this year -- in a riparian habitat just south of downtown Phoenix.