Mammals Archives - Page 32 of 36

July 29, 2010March 4, 2026

Utah’s Recent Pinyon Migrations and the Prospects for Climate Change

In the late 1970’s, springtime in the American West warmed abruptly by 2 degrees Fahrenheit in the valleys, double that higher up. Our average onset of Spring now comes a week earlier across the West. If these are the first signs of climate change, even longer growing seasons will trigger not just earlier blooms but also northward plant migrations.

The past provides us with lessons about plant migrations. A thousand years ago, one-needle pinyon hopped from the Raft River Mountains in Utah to City of Rocks, Idaho. Across Utah, two-needle pinyon leaped over the Uintas to Flaming Gorge. We know this from radiocarbon dates on pinyon pine needles taken from ancient nest heaps of packrats preserved in caves. According to Dr. Julio Betancourt of the U.S. Geological Survey, who uses these packrat middens and tree rings to reveal past plant migrations, these recent advances by Utah’s two pinyon pines followed the Medieval Climate Anomaly, a period from 900 to 1300 AD marked by warming in Europe and severe drought in Utah.

Droughts figure prominently in Dr. Betancourt’s view of tree migrations. Droughts trigger bark beetle infestations, wildfires, and tree dieoffs, opening up niches for regeneration. When the drought abates, the resident tree species typically return. With long-term warming, however, other species can move in from lower elevations or further south. Dead trees now abound on Utah’s landscape, and Dr. Betancourt thinks that we are on the verge of a new spate of tree migrations.

This go around, which species retreat or advance will depend on new factors, including human fragmentation of the landscape and accelerated dispersal of native and non-native species that hitch rides with us. To conserve ecological goods and services associated with some species, Dr. Betancourt argues, we will have to manage for these plant migrations.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Text: Julio Betancourt USGS NRP Tucson: Biotic Response to Climate Variability
Faculty and Staff > Julio Betancourt

Additional Reading:

USGS National Research Program: Tucson AZ
https://wwwpaztcn.wr.usgs.gov/home.html

Climate Change and the Great Basin, Jeanne C. Chambers, USDA Forest Service, Rocky Mountain Research Station, Reno, NV, 2008,

A Database of Paleoecological Records from Neotoma Middens in Western North America, USGS/NOAA North American Packrat Midden Database, https://esp.cr.usgs.gov/data/midden/ (Accessed 27 August 2009)

May 27, 2010May 2, 2016

Utah’s Desert Fox

Kit Fox, click to view larger image, Photo Courtesy and Copyright © 2009 Bryan Kluever, graduate research assistant, Utah State University Department of Wildland Resources — PhD student Bryan Klueve
with an adult kit fox
that was captured
with a box trap.
Kit foxes are weighed,
fitted with a radio collar,
and then released
Courtesy & Copyright © 2010
Bryan Kluever
Graduate Research Assistant
Utah State University
Dept of Wildland Resources

Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

The kit fox just might be Utah’s cutest mammal. Weighing in at four to five pounds or so, the kit fox is about a third of the size of the more common red fox.. The kit fox has delicate cat- like features and it has comically large, furry ears. It’s desert-colored coat is tinged with rusty orange finishing in a long black-tipped bushy tail.

The kit fox is the only desert dwelling fox in North America. In Utah, you’ll find it mostly in the western part of the state, where it lives off field mice and jackrabbits as well as insects, birds, amphibians and fish.

The kit fox has evolved a number of adaptations to deal with the desert’s harsh conditions.. First of all those big ears aren’t just for looks. They help the kit fox dissipate body heat through evaporative cooling.

Secondly, kit foxes are nocturnal, avoiding the high temperatures of the daytime hours. During the day they lounge in subterranean dens.

Kit fox legs are relatively short for a fox. That helps them zig-zag through the brush when chasing prey or being chased. And the pads of their paws are furry which gives them better traction in the sandy soil of desert habitats.

Long droughts are common in desert environments and kit foxes have developed ways to deal with them. During a drought, fewer vixens breed and litters become smaller. Kit fox families maintain large territories—larger than necessary for normal years. So when a drought hits, and the population of prey species plummets, the foxes have a larger area in which to hunt.

Kit foxes get top marks in water conservation. Little goes in and little comes out.. A kit fox can exist for many months without ever drinking water. Instead, the fox can draw water from the food that it eats. And that water is used with great efficiency. Little is lost through metabolic processes such as urination, defecation breathing and panting.

Too see pictures of the diminitive kit fox, go to www.wildaboututah.org

Thanks to Brian Kleuwer and Mary-Ann Muffoletto of Utah State University’s College of Natural Resources for supporting this Wild about Utah topic.

For Wild About Utah and Stokes Nature Center, I’m Holly Strand.
Credits:
Images: Courtesy & Copyright Bryan Kluever, USU Department of Wildland Resources
Text: Mary-Ann Muffoletto, Utah State University College of Natural Resources

Additional Reading:

White, P. J. and K. Ralls. 1993. Reproduction and spacing patterns of kit foxes relative to changing prey availability. Journal of Wildlife Management 57:861–867 The Wildlife Society, https://si-pddr.si.edu/dspace/bitstream/10088/510/1/White1993.pdf

Kit Fox (Vulpes macrotis), Wildlife Notebook Series No. 9, Utah Division of Wildlife Resourceswildlife.utah.gov/publications/pdf/2010_kit_fox.pdf

Kit Fox (Vulpes macrotis), Species Fact Sheets, Utah Conservation Data Center, Utah Division of Wildlife Resources, https://dwrcdc.nr.utah.gov/rsgis2/Search/Display.asp?FlNm=vulpvelo

May 13, 2010January 31, 2026

Bats and Echolocation

Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

There are approximately 4600 mammal species in the world. A fifth—yes, 20%– of these species are bats. They are found everywhere except Antarctica. In Utah they are found at every elevation and in every ecosystem.

Bats are the only mammal that flies. “You forgot about humans,” my very precise husband points out. Well, OK bats are the only mammal that flies without a license and an airplane.

The majority of bats have smallish eyes perhaps leading to the expression “blind as a bat.” But bats are not at all blind. All of them can see and some rely solely on vision for both navigation and foraging. But most bats also have a sixth sense—called echolocation–to navigate and detect prey.

Click for larger picture, Mariana Fruit Bat from the Mariana Islands, Courtesy U.S. Fish and Wildlife Service, Photographer: Ann Hudgins — Mariana Fruit Bat
From the
Northern Mariana Islands
Photographer: Ann Hudgins
Courtesy US FWS

Echolocation refers to the process of sending out pulses of sound and listening to
the echoes to locate or avoid objects. Bats emit pulses of high frequency sound from their larynx or voicebox. These sounds are ultrasonic which means that they occur at frequencies beyond the range that humans can hear. The sounds are emitted through the mouth in some bats and through the nose in others.

The sounds bounce off external objects and echoes are returned to the bat’s ear. The size and shape of the bat’s ears help amplify the returning sound. The sound travels through the ear and is converted to vibrations in the inner ear fluid and then on to the brain via the auditory nerve.

Bat brains have unique structures that compare the features of the original sound pulse against the characteristics of the returning echoes. By assembling and assessing the return data, bats can know the direction of and distance of an object. Some bat species have evolved echolocation to such a degree that they can even distinguish shape among individual species of insects.

Click for larger picture, Townsend's Big-eared Bat, Courtesy National Park Service — Townsend’s Big-eared Bat
Courtesy National Park Service

Because of echolocation bats are phenomenal hunters in low light conditions. A single little brown bat can catch 300 to 3,000 insects per night, and a nursing mother little brown bat eats more than her body weight each night — up to 4,500 insects. Hmm. That’s a lot of mosquitoes. I think I’ll invite some bats to my backyard this summer.

Thanks to the Marie Eccles Foundation –the Russell Family for supporting Stokes Nature Center programs.

For Wild About Utah and Stokes Nature Center, I’m Holly Strand.

Credits:
Images: Courtesy US FWS and USDA Forest Service
Text: Stokes Nature Center: Holly Strand

Sources & Additional Reading

Bat Conservation International. 1997. Bat Chat: An Introduction to Echolocation
https://www.batcon.org/, https://www.batcon.org/resources/media-education/learning/bat-squad/bat-squad-ep-4-bat-chat-join-the-bat-squad

Wilson, Don E. 1997 Bats in Question: The Smithsonian Answer Book. Smithsonian Institution Press, Washington, DC https://www.amazon.com/Bats-Question-Smithsonian-Answer-Book/dp/1560987391

Bats Live, Prince William County Public Schools, Manassas, VA, https://batslive.pwnet.org/

Bat Week 2015
Sometimes misunderstood, bats are important and fascinating animals. Watch this video to learn some bat facts, find out what challenges are facing bats today and what you can do to help #savethebats.
Bat Week Video

13 Facts About Bats, US Department of the Interior, Blog, 10/24/2016, https://www.doi.gov/blog/13-facts-about-bats

White-nose syndrome: a disease of bats, Wildlife Blog, Utah Division of Wildlife Resources, https://wildlife.utah.gov/news/wildlife-blog/724-white-nose-syndrome-a-disease-of-bats.html

Building nurseries for big-eared bats, Wildlife Blog, Utah Division of Wildlife Resources, https://wildlife.utah.gov/news/wildlife-blog/707-building-nurseries-for-big-eared-bats.html

April 29, 2010March 4, 2026

Beavers: The Original Army Corps of Engineers

Click for larger picture, Beaver with branch in water, Courtesy US FWS — Beaver with branch in water
Courtesy US FWS,
Steve Hillebrand, Photographer

Hi, I’m Holly Strand from Stokes Nature Center in beautiful Logan Canyon.

Beavers and beaver dams are a common feature of the Utah landscape. You’ll see the dams on smaller streams and side channels, constructed of branches, downed trees and mud. The still, deep water of the resulting pond creates ideal conditions for a beaver lodge. Beavers can escape and hide from predators by slipping into the pond and disappearing into the lodge. Beavers also use their ponds to cache their favorite
food—aspen and willow.

Because of their tree cutting and dam making skills, humans tend to have two divergent opinions of beavers: 60-pound nuisance or environmental engineer.

Click for larger picture, Beaver Lodge, Courtesy US FWS — Beaver lodge
Courtesy US FWS
Hans Stuart, Photographer

Beavers are considered a nuisance when they gnaw down trees that humans want to keep. Dams can flood roads or stop up irrigation canals. When beaver activity conflicts with human interests, they—the beavers–are likely to be trapped and killed.

However, beaver activity has many positive environmental consequences that we are just beginning to appreciate. Wetlands created by beaver dams help soak up sediments, improving downstream water quality. Because of beaver dams, the winter snowpack isn’t lost in a short spring pulse, This results in a more constant stream flow through the summer –and that’s important as Utah’s climate is predicted to become drier. Finally, beaver dams enhance habitat for many other fish and wildlife species and plants.

Click for larger picture, Beaver in pond, Courtesy US FWS — Beaver in pond
Courtesy US FWS
Steve Hillebrand, Photographer

According to Dr. Joe Wheaton, a geomorphologist at Utah State University, there’s a lot of untapped potential for employing beaver engineers in stream and floodplain restoration. Say you want to restore a stream by reconnecting it with its floodplain. You need to excavate channels, redirect stream flow, revegetate and nurture the
area for a long period of time. To accomplish this, you often need a
number of highly trained professionals and some large Tonka toys.

Alternatively –under the right conditions– you might transplant a
colony of beavers and let them apply their vigorous work ethic to your
landscape and get quite satisfying results.

Recognizing that nuisance beavers can be rehabilitated into hard
working wetland engineers and stream habitat restorationists, the Utah
Division of Wildlife Resources has rolled out the state’s first beaver
management plan in 2010. This plan encourages live trapping of entire
families of beavers in nuisance areas and moves them to specific sites where their
environmental services can be appreciated and put to use.

Click for larger picture, Beaver in snow, Courtesy US FWS — Beaver in snow
Courtesy US FWS

Thanks to the USU College of Natural Resources for supporting this Wild about Utah topic.

For Wild About Utah and Stokes Nature Center, I’m Holly Strand.

Credits:
Images: Courtesy US FWS, Photographers: Steve Hillebrand and Hans Stuart, https://images.fws.gov
Text: Holly Strand, Stokes Nature Center

Sources & Additional Reading

Collen, P. and R.J. Gibson. 2001. The general ecology of beavers (Castor spp.), as related to their influence on stream ecosystems and riparian habitats, and the subsequent effects on fish – a review. Reviews in Fish Biology and Fisheries 10: 439–461, 2001. https://web.archive.org/web/20230202160926/https://www.researchgate.net/publication/227028536_The_general_ecology_of_beavers_Castor_spp_as_related_to_their_influence_on_stream_ecosystems_and_riparian_habitats_and_the_subsequent_effects_on_fish_-_A_review [ Accessed May 1, 2010]

Prettyman, B. 2009. Utah wildlife: Leave it to the beavers. Article in Salt Lake Tribune, October 16, 2009. https://www.sltrib.com/ci_13570110 [ Accessed April 29, 2010]

Smithsonian Castor Canadensis Information Page https://www.mnh.si.edu/mna/image_info.cfm?species_id=32 [ Accessed April 29, 2010]

Big Bend Habitat Restoration Project: A Natural Work of Heart, Open Spaces-A Talk on the Wild Side, US FWS, https://www.fws.gov/news/blog/index.cfm/2016/3/25/Big-Bend-Habitat-Restoration-Project-A-Natural-Work-of-Heart [Accessed March 31, 2016]

Beaver Dams Strengthened by Humans Help Fish Rebound
60-Second Science – July 25, 2016 – By Jason G. Goldman02:29 https://www.scientificamerican.com/podcast/episode/beaver-dams-strengthened-by-humans-help-fish-rebound/ Also available through the podcast https://itunes.apple.com/us/podcast/60-second-science/id189330872?mt=2

Restoring Degraded Waters, One Pest at a Time, Utah State Magazine, Utah State University, December 7, 2021, https://utahstatemagazine.usu.edu/environment/restoring-degraded-waters-one-nuisance-at-a-time/

Goldfarb, Ben, Eager: The Surprising, Secret Life of Beavers and Why They Matter, Chelsea Green Publishing, March 8, 2019, https://www.amazon.com/Eager-Surprising-Secret-Beavers-Matter/dp/1603589082/ref=asc_df_1603589082/