From Field to Collection: “Tales” of the Bushy-tailed Woodrat (Neotoma cinerea)

Guest post by Katharine Corriveau

Biologists always return from the field with stories. Sometimes the stories involve encounters with strange people or untimely weather, but often they involve animals. And, of course, some animals seem to make a bigger impression on us than others. The bushy-tailed woodrat is certainly one of these.

A Curious Collector

The bushy-tailed woodrat (Neotoma cinerea) has long been a well-established yet somewhat inconspicuous inhabitant of prairies and rocky, mountainous habitats in Western North America.

Left: Bushy-tailed woodrat (Neotoma cinerea) in a Tomahawk trap, Leadore, ID. Photo by Tatiana Gettelman, 9 July 2007.  Right: Bushy-tailed woodrat (Neotoma cinerea). Photo by Oregon Caves (NPS), 9 June 2009.

Like curators, woodrats are renowned collectors, exhibiting an insatiable desire to cache and store food items and other trinkets, earning them the moniker of ‘pack rat’. Contrary to the impression given off by their middens – built with plant material, rocks, animal droppings and other items glued together with crystalized urine (Government of Yukon, 2014; Horowitz, n.d.; Trapani, 2003; USGS, 2013) – woodrats keep the interior of their homes fastidiously organized and well-maintained (Milius, 2014). Woodrats are also known for their affinity for shiny objects – often ‘decorating’ their middens with human artifacts such shotgun shells, tinfoil, pennies, mylar balloons, soda cans, bottle caps, Doritos bags and pieces of wire or glass (Horowitz, n.d.; Milius, 2014; USGS, 2013).

collection drawer

Bushy-tailed woodrat specimens in storage at the MVZ. Note that the skins in the rear of the tray are kept separately from the skulls at the front of the tray. Photo by Katharine Corriveau.

MVZ Bushy-Tails

At the Museum of Vertebrate Zoology (MVZ), we house 824 bushy-tailed woodrat specimens, spanning 1898 through 2013, and covering western North America from northern British Columbia down to southern California and Arizona, and east to the Dakotas. This breadth of specimens allows researchers to assess how the species has changed over time in response to environmental trends and anthropogenic disturbances, among other factors.

Some of these specimens were collected by Seth Benson between 1939 and 1960, while he occupied the position of Curator of Mammals. One specimen in particular (MVZ Mammals 105516) was collected on July 7, 1946, at the locality pictured below in Mono County, California (read more about this collecting trip here). It is quite rare to have photographs of the specific habitats in which our older specimens were collected, so this image holds significance by allowing us to return to the same spot and see how the landscape has changed over the past 50+ years.

Left: MVZ Mammal Specimen 105516, collected by Seth B. Benson on July 7th, 1946, in Sweetwater Canyon (Sweetwater Mtns), Mono Co., California. (Photos by Katharine Corriveau) Right: This photo, entitled “Habitat site of trap line #5”, was taken by J. H. Severaid on July 7th, 1946, in the Sweetwater Canyon of the Sweetwater Mountains in Mono County, California (Photo courtesy of the MVZ Archives, Image Number 12645).

Left: MVZ Mammal Specimen 105516, collected by Seth B. Benson on July 7, 1946, in Sweetwater Canyon (Sweetwater Mtns), Mono Co., California. Photos by Katharine Corriveau.
Right: This photo, entitled “Habitat site of trap line #5”, was taken by J. H. Severaid on July 7, 1946, in the Sweetwater Canyon of the Sweetwater Mountains in Mono Co., California. Photo courtesy of the MVZ Archives, Image Number 12645.

The two bushy-tailed woodrat specimens depicted below were also collected in the Sweetwater Mountains, both at nearly the same location in Swager Canyon. However, one was collected during Benson’s 1946 expedition (left), while the other was collected by current Curator of Mammals (Emeritus) James Patton in 2009 (right). This provides a concrete example of how we can compare populations living in the same geographic area, over 60 years apart.

MVZ Mammal Specimens 105513 (left) and 224243 (right). Though both specimens were collected in the same location (Swager Canyon, Sweetwater Mountains, Mono Co., CA), specimen 105513 was collected in 1946 by past MVZ mammal curator Seth B. Benson, whereas specimen 224243 was collected in 2009 by current curator of mammals (Emeritus) Jim Patton. (Photos by Katharine Corriveau)

MVZ Mammal Specimens 105513 (left) and 224243 (right). Though both specimens were collected in the same location (Swager Canyon, Sweetwater Mountains, Mono Co., CA), specimen 105513 was collected in 1946 by past MVZ mammal curator Seth B. Benson, whereas specimen 224243 was collected in 2009 by current curator of mammals (Emeritus) Jim Patton. Photos by Katharine Corriveau.

By studying bushy-tailed woodrat specimens and their middens, we can learn much about how ecosystems have changed over past decades and centuries. As useful tools for scientists, it is critical that museums such as the MVZ preserve current woodrat collections and continue to collect specimens in order to maintain an intact timeline.

Tales of the Bushy-Tail

All this said, museum specimens are much more than a series of study skins that help us better understand our changing world. In the field, biologists regularly encounter living animals, and these experiences turn into narratives that are told again and again. Some animals in particular seem to stick with us long after others have dimmed – the woodrat is certainly one of these.

Indeed, I had a personal experience with the bushy-tailed woodrat while conducting field work in British Columbia in 2011. One night, on a mountain peak, my field assistant and I were awoken quite suddenly by a shuffling noise outside our tents. After grappling for our headlamps and bear sprays in the dark, we caught the furry offender in the act. A bushy-tailed woodrat was chewing our hiking boots, and had completely chewed its way through some of the laces. Needless to say, we brought our hiking boots into our tent and kept them close for the remainder of our field season.

Unsurprisingly, I’m not alone in having experienced the bushy-tailed woodrat (and related species) displaying unique and often downright funny behaviors. Following is a compilation of stories involving these fascinating creatures, illustrated with photos pulled from the MVZ Archives.

Curiosity Killed the Woodrat?

According to University of Nevada (Reno) graduate student Angela Hornsby, woodrats appear to be exceedingly curious animals:

I’ve had bushy-tails come out in the evening and watch us set traps. One comes to mind in Wyoming in 2008 – she came out and watched us for a good long while, and only got scared off when we decided to climb up and test her personal space. We caught her the next morning and saw that she had a bobbed tail, the last 1/3 gone, which I like to think was a casualty of her curiosity on some previous occasion.

(A. Hornsby, personal communication, 9 July 2014)

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Bushy-tailed woodrat midden in a rock crevice in the Panamint Mountains of Inyo Co., CA. Photo by Joseph Dixon (1917), courtesy of the MVZ Archives, Image Number 2558.

Cabin Dwelling Thieves

Woodrats also seem to enjoy sharing both home and material goods with humans:

Back in the winter of 1948-1948, Mr. and Mrs. George L. Mayer were hired to maintain properties in Yosemite National Park during the off-season. The couple was welcomed to their winter accommodations by a pair of bushy-tailed woodrats who “had a beautiful nest built of slices of stale bread” beneath a counter (Mayer, 1949, p. 96). Though careful to put things away and keep clutter to a minimum, they awoke each morning to “a neat pile of spoons, spectacles, rolls of film [or] scissors”, and often heard the pair awkwardly dragging large objects through tight spaces (Mayer, 1949, p. 96). Fascinatingly, Mr. & Mrs. Mayer soon found a way to end the pilfering – they started placing “a plate of assorted scraps on the counter for them” before retiring in the evening (Mayer, 1949, p. 97). Their furry housemates apparently loved this arrangement, cleaning the plate every night and no longer venturing into the kitchen, looking for things to ‘steal’ (Mayer, 1949).

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Woodrat midden in Fresno Co., CA. Photo by Joseph Dixon (1916), courtesy of the MVZ Archives, Image Number 2293.

Another account of theft was related by MVZ curator Eileen Lacey (personal communication, 9 July 2014). One of her former post-docs lost her watch while conducting field work at the Hastings Reserve and staying in the “old Red House”. Suspiciously, subsequent researchers staying in the house were often awoken around 3 am by a strange beeping noise. When the cabin was eventually demolished, a large woodrat nest was uncovered beneath the floorboards – and lo and behold, in the nest was the lost watch!

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“Bushy-tailed Wood Rat – in life”. Taken by Joseph Dixon on September 2, 1916 near Bullfrog Lake in Fresno Co., California. Photo courtesy of the MVZ Archives, Image Number 2253.

Exacting Foodies

Bushy-tailed woodrats can also be peculiar in the way that they set out their haypiles, the mounds of plant material used as food caches. “Usually you’ll see big mounds of vegetation outside their house, but a couple of times I’ve seen long pieces of vegetation laid almost perfectly side by side on a flat rock” (A. Hornsby, personal communication, 9 July 2014).

Similarly, British Columbian blogger Wayne J. Lutz began to notice that the vegetables in his garden were being mysteriously ‘harvested’ and organized into species-specific mounds – “Parsley was piled with parsley, spinach with spinach, carrot tops were with carrot tops, and strawberries with strawberries. Such a neat farmer” (Lutz, 2007). The mystery farmer, a bushy-tailed woodrat, was soon apprehended when it was lured into a Havahart 0745 live trap with a tempting peanut butter treat (Lutz, 2007).

Another hilarious and slightly sickening event involving woodrat food stashes took place over Christmas of 1849, where gold-seeker William Manly and his party became stranded in Death Valley after taking a failed ‘short-cut’ from Salt Lake City to California (Eaton, 2003). While exploring a canyon in the area, Manly came across “balls of a glistening substance looking something like varigated [sic] candy stuck together” (as cited in Eaton, 2003). Believing the balls to be the remains of a Native American food cache, he distributed them to his party members, who described the taste as “sweet but sickish” (as cited in Eaton, 2003). Rather than belonging to a local Native American tribe, it is likely that the balls were made by native woodrats, who accumulate inedible foodstuffs in their middens, which they also use as latrines (Eaton, 2003). Since the natural biodegradation process is severely compromised in desert ecosystems due to the lack of moisture, the woodrat urine dries up, encasing the midden’s plant matter over time and creating the balls that the Manly party unknowingly ate (Eaton, 2003).

“Bushy-tail woodrat rock” in the Panamint Mountains (Inyo Co.) of Death Valley National Monument – possibly near where the William Manly incident took place (Photo by Joseph Dixon (1917), courtesy of the MVZ Archives, Image Number 2566).

“Bushy-tail woodrat rock” in the Panamint Mountains (Inyo Co.) of Death Valley National Monument – possibly near where the William Manly incident took place. Photo by Joseph Dixon (1917), courtesy of the MVZ Archives, Image Number 2566.

For Research and Storytelling

As we’ve seen, the woodrat is not only a valuable research tool, but a fascinating mammal with the power to capture our imaginations and impress us with their cunning and curious behaviors.

So next time you’re exploring the open plains, rocky crevices, or talus slopes of Western North America, keep your eyes peeled for signs of the curious bushy-tailed woodrat. A tangle of twigs low to the ground or meticulously laid-out piles of vegetation might give you clues to his whereabouts. But beware – if you do venture into woodrat territory, hold on to your personal belongings! A cunning “pack rat” might take a liking to something shiny and steal it away in the night.

Katharine Corriveau is Outreach Coordinator at the Museum of Vertebrate Zoology, UC Berkeley, and a Museum Studies Graduate Student at John F. Kennedy University.

Next time on Cracking the Collections:

October 10 – Our very first Careers in Collections post by Carrie Eaton – The Joys of a Small University Museum!

References

Eaton, J. (2003, December 12). Potent packrat leavings tempted starting 49ers. The Berkeley Daily Planet. Retrieved from http://www.berkeleydailyplanet.com/issue/2003-12-12/article/17931?headline=Potent-Packrat-Leavings-Tempted-Starving-49ers&status=301

Government of Yukon. (2014). Bushy-tailed Woodrat (Neotoma cinerea). Retrieved from http://www.env.gov.yk.ca/animals-habitat/mammals/bushytrailedwoodrat.php

Horowitz, E. (n.d.). Montana Outdoors Portrait: Bushy-tailed Woodrat (Neotoma cinerea). Montana Outdoors. Retrieved from http://fwp.mt.gov/mtoutdoors/HTML/articles/portraits/woodrat.htm

Lutz, W. J. (2007, November 16). Pesky Bushy Tailed Woodrats [Blog post]. Powell River Books Blog. Retrieved from http://powellriverbooks.blogspot.com/2007/11/in-october-when-we-returned-to-our.html

Mayer, D. R. (1949). Glacier Point in winter. Yosemite Nature Notes, XXVIII(7): 96-98. Retrieved from http://www.yosemite.ca.us/library/yosemite_nature_notes/28/28-7.pdf

Milius, S. (2014, February 14). ‘Packrat’ is the new term for ‘really organized’. Science News. Retrieved from https://www.sciencenews.org/article/%E2%80%98packrat%E2%80%99-new-term-%E2%80%98really-organized%E2%80%99

Trapani, J. (2003). Neotoma cinerea. Animal Diversity Web. Retrieved from http://animaldiversity.ummz.umich.edu/accounts/Neotoma_cinerea/

United States Geological Survey (USGS). (2013). Small mammals of North Dakota: Bushy-tailed Woodrat (Neotoma cinerea). Northern Prairie Wildlife Research Center. Retrieved from http://www.npwrc.usgs.gov/resource/mammals/mammals/woodrat.htm

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