Reptiles Archives - Page 7 of 9

January 31, 2013January 5, 2024

Desert Tortoises

Click for a larger view of an adult Desert Tortoise. Courtesy & Copyright 2009 Kevin Durso, Photographer — Adult Desert Tortoise
*Gopherus agassizii*
Courtesy & Copyright 2009
Kevin Durso, Photographer

Adult Desert Tortoise
*Gopherus agassizii*
Courtesy & Copyright 2009
Kevin Durso, Photographer

Adult & Juvenile Desert Tortoise
*Gopherus agassizii*
Courtesy & Copyright 2009
Andrew Durso, Photographer

Juvenile Desert Tortoise
*Gopherus agassizii*
Courtesy & Copyright 2009
Andrew Durso, Photographer

Tortoises are turtles that live their whole lives on land. Most tortoises are native to Africa and South America, but several are North American including the Desert Tortoise whose range extends to southwestern Utah. Their shells consist of enlarged scales called scutes. These scutes are tan, black, or dull orange, and etched with many concentric lines, like the growth rings of a tree. Desert Tortoises look like grizzled old men, even the Oreo-sized hatchlings, which over several decades will grow to football size.

Desert Tortoises mate in the spring, and a few months later, the female lays her 5 or 6 eggs in a funnel-shaped pit dug in the sand. The sex of the baby Desert Tortoises is determined by the sun’s heating rather than by genetics – cooler incubation yields males, hotter eggs produce females, with a mix of sexes developing at intermediate temperatures.

Desert Tortoises primarily eat the flowers of desert plants such as globemallow and threeawn. Because most desert plants only bloom briefly each spring, tortoises must eat a lot between April and June, although they can be active during all but the coldest months. Being toothless, they grind up their vegetarian fare using a specialized bone embedded in their jaw muscles. Like cows and other herbivores, they depend on microbes in their gut to digest the cellulose in their diet. Even more than food, water is precious to a Desert Tortoise. They have little to spare, sometimes going for months without urinating, but will pee defensively if handled. Resist the temptation to pick them up or you will rob the poor animal of its water supply for the entire year.

Once found throughout the Mojave and Sonoran deserts, Desert Tortoises are much less common than they were a century ago. They have not fared well with urbanization, highways, and off-road vehicle traffic. An upper respiratory tract disease can also be lethal, especially when crowded or stressed, as in captivity. Desert Tortoises are now protected by the US Endangered Species Act.

Today’s program was written by Andrew Durso of USU’s biology department.

Credits:

Theme: Courtesy & Copyright Don Anderson Leaping Lulu
Images: Courtesy & Copyright Andrew Durso and Kevin Durso
Text: Andrew Durso, https://www.biology.usu.edu/htm/our-people/graduate-students?memberID=6753

Additional Reading:

Gopherus agassizii, Turtle Conservancy, https://www.turtleconservancy.org/news/tag/Gopherus+agassizii

Grover, Mark C., DeFalco, Lesley A, Desert Tortoise(Gopherus agassizii): Status-of-Knowledge, Outline With References, USDA, 1995, https://www.fs.usda.gov/research/treesearch/30627

Desert Tortoise, Gopherus agassizii, Mojave National Preserve, https://www.mojavenp.org/Gopherus_agassizii.htm

Gopherus agassizii (COOPER, 1861), The Reptile Database, Peter Uetz and Jakob Hallermann, Zoological Museum Hamburg,
https://reptile-database.reptarium.cz/species?genus=Gopherus&species=agassizii

Desert Tortoise, Species, Utah Division of Wildlife Resources, Utah Department of Natural Resources, https://fieldguide.wildlife.utah.gov/?species=gopherus%20agassizii

Desert Tortoise Information and Collaboration, Mojave Desert Ecosystem Program, https://www.mojavedata.gov/deserttortoise_gov/index.html

Red Cliffs Desert Reserve, http://www.redcliffsdesertreserve.com

January 24, 2013September 7, 2019

Tracking Wildlife in Winter

Click to view a larger photograph of jumping mouse tracks, Photo Courtesy & Copyright Mark Larese-Casanova — Jumping Mouse Tracks
Photo Courtesy & Copyright 2011
Mark Larese-Casanova

Moose Tracks in Snow
Photo Courtesy & Copyright 2011
Mark Larese-Casanova

$Click to view a larger photograph of cottontail rabbit browse and \scat, Photo Courtesy & Copyright Mark Larese-Casanova$ Cottontail Rabbit Browse & Scat
Photo Courtesy & Copyright 2011
Mark Larese-Casanova

Click to view a larger photograph of moose tracks in snow, Photo Courtesy & Copyright Mark Larese-Casanova — Jumping Mouse Tracks
Photo Courtesy & Copyright 2011
Mark Larese-Casanova

Moose Tracks in Snow
Photo Courtesy & Copyright 2011
Mark Larese-Casanova

$Click to view a larger photograph of cottontail rabbit browse and \scat, Photo Courtesy & Copyright Mark Larese-Casanova$ Cottontail Rabbit Browse & Scat
Photo Courtesy & Copyright 2011
Mark Larese-Casanova

Hi, this is Mark Larese-Casanova from the Utah Master Naturalist Program at Utah State University Extension.

The cold depth of winter is a time when many animals are hiding- either hibernating until the thaw of spring, or finding shelter and warmth in burrows, under logs, or in the tangled branches of evergreen trees.

However, snow falls in much of Utah, and even a dusting can reveal the stories of wildlife in winter. It’s a bit like solving a mystery. By reading the clues of animal tracks, we can know not only the type of animal that made them, but also where they were going and what they were doing.

The most obvious clue is the size of a track. Smaller animals make smaller tracks, and also sets of tracks that are generally closer together.

The shape of an animal track is also very revealing. Members of the canine family, including domestic dogs, coyotes, and fox, show four toes in front, each with a visible claw. Felines, including bobcats and mountain lions, also show four toes, but no claws. Tracks from members of the weasel family, such as mink, ermine, and skunks, show five toes, each with a claw. Raccoon, squirrel, and mouse tracks almost look like they were made by tiny human hands. The long tails of some animals, including deer mice, jumping mice, and weasels, often leave a characteristic line through the center of a set of tracks.

Combining the size and shape of tracks reveals further details about wildlife. The three inch long cloven hoof print of a mule deer is easily recognizable. An elk track looks almost identical, but is about four inches long. A similar moose track is even larger at six inches long.

Figuring out which animal made a track is only half of the story. If we follow tracks, we’ll surely find clues about an animal’s daily life. Wildlife often gather around sources of water that aren’t frozen, which are critical to winter survival. Perhaps rabbit tracks lead under a spruce tree where browsed branches and droppings indicate a frequent feeding spot. Maybe mouse tracks lead from tree to rock to log as it avoids owls and hawks.

While we are much more likely to see wildlife during the warmer months, winter gives us a chance to unravel the story of daily survival during the most difficult time of the year in Utah.

For Wild About Utah, I’m Mark Larese-Casanova.

Credits:
Images: Courtesy and Copyright Mark Larese-Casanova
Text: Mark Larese-Casanova

Additional Reading:

Canadian Wildlife Federation: Tracking Down Winter Wildlife. https://www.cwf-fcf.org/en/action/how-to/outside/tracking-down-winter-wildlife.html

Murie, O. J. (1982). Animal Tracks. Peterson Field Guides. New York, NY: Houghton Mifflin. https://www.amazon.com/Peterson-Field-Guide-Animal-Tracks/dp/061851743X

Vermont Nature and Outdoors: Tracking Winter Wildlife. https://www.ruralvermont.com/vermontweathervane/issues/winter/97012/vins97012_tracking.shtml

May 31, 2012March 4, 2018

Rubber Boas

Mention boas and we imagine steaming South American rain forests, home to emerald tree boas and enormous boa constrictors. However, the canyons of northern Utah are home to the rubber boa, one of only two native North American boas. Rubber boas range from northern Utah west to the Pacific coast and north to Vancouver. An adult rubber boa resembles a thin kielbasa sausage in size and shape, having both a blunt tail and head. Juveniles are the size of a crayon. A rubber boa’s leathery skin is the color of creamy coffee, its small scales giving it a rubbery texture. Like other boas, it has vestigial hind legs, called spurs, with which males stimulate females during mating.

Rubber boas are active at night during the summer. In spring they can be among the first snakes to come out from the talus slopes and rock crevices where they hibernate. In Cache County, rubber boas can be found basking from March through November. From April to August, pregnant females use these rocky habitats to maintain body temperatures around 88 degrees. When not pregnant, rubber boas stay remarkably cool for a snake, around 57 degrees. In late summer, females bear an average of four live young. They only reproduce every two to three years, so juvenile survival must be quite high. In captivity, rubber boas can live 30 years or more.

It’s hard to imagine these docile, slow-moving snakes as predators, but rubber boas eat mammals, birds, reptiles and eggs. Like other boas, they have no venom and kill by constriction. Rubber boas often consume whole litters of nestling mice, voles, pocket gophers, shrew and moles. The snakes fend off the protective rodent parents with their short, blunt tails, which often bear bite scars. Both rubber boas and rodents evolved in Asia about 45 million years ago which suggests that they have been predator and prey for a very long time.

Thanks to Andrew Durso, Utah State University herpetology student, for today’s essay.

This is Linda Kervin for Bridgerland Audubon Society.

Credits:

Images: Courtesy and Copyright Andrew Durso and Edmund ‘Butch’ Brodie

Text: Andrew Durso, Utah State University herpetology doctoral candidate, https://www.biology.usu.edu/htm/our-people/graduate-students?memberID=6753

Additional Reading:

Life is Short, but Snakes are Long: https://snakesarelong.blogspot.com/2012/04/utahs-boa.html

Utah Division of Wildlife Resources: https://dwrcdc.nr.utah.gov/rsgis2/search/Display.asp?FlNm=charbott

Cox DT & WW Tanner (1995) Snakes of Utah. Bean Life Science Museum, Provo, UT https://www.amazon.com/Snakes-Utah-Douglas-C-Cox/dp/0842523316

Ernst CH & EM Ernst (2003) Snakes of the United States and Canada. Smithsonian Institution Press, Washington D.C. https://www.amazon.com/Snakes-United-States-Canada-Ernst/dp/1588340198

October 20, 2011July 18, 2020

Desert Animals-Extreme Survivors

Click to view larger image of Kangaroo Rat, Photo Courtesy US FWS, George Harrison, Photographer — Collared lizard
Photo Courtesy US FWS
Lawrence Gamble, Photographer

Kangaroo Rat
Photo Courtesy US FWS
George Harrison, Photographer

Gila Monster
Photo Courtesy & © Daniel D. Beck
Central Washington University

Couch’s Spadefoot Toad
Photo Courtesy US FWS
Gary M. Stolz, Photographer

Hi, this is Mark Larese-Casanova from the Utah Master Naturalist Program at Utah State University Extension. Desert Animals-Extreme Survivors

The three main deserts of Utah- the Great Basin to the west, the Colorado Plateau to the east, and the Mojave Desert in the southwest corner of the state- are each inhabited by animals that have unique adaptations for surviving the extreme heat, dryness, and sometimes cold temperatures of the desert.

Many animals survive in Utah’s deserts through behavioral adaptations. During the heat of the day, most animals can be found underground in burrows, or simply sitting in the shade of a shrub or tree. Reptiles, such as the desert tortoise and gila monster, spend almost all of their time in a burrow or under a rock. Many birds and mammals are most active near dawn and dusk when temperatures are coolest, yet there is enough light to see. Many bats, snakes, and rodents are nocturnal, and are only active at night!

Morphological adaptations, related to the shape or color of an animal’s body, are also important for living in the desert. The collared lizard has long legs and toes that keep its body away from the hot ground, reducing heat absorption. White-tailed antelope ground squirrels will use their bushy tails as a shade umbrella, and the long ears of the jackrabbit aid in dispersing body heat.

The kangaroo rat has perhaps the most amazing combination of adaptations for desert survival. Not only does it live in a burrow and is nocturnal, but it recaptures it’s own body moisture by storing food within its burrow. Dry seeds absorb moisture from the kangaroo rat’s breath, which condenses more readily in the cooler underground temperatures.

Physiological adaptations relate to a change in body function to aid survival in the desert. The kangaroo rat has such complex kidneys that it is able to retain as much water as possible. It also has specialized tissues in its nasal passages that help it retain much of the moisture that is normally lost through breathing. If the desert gets too hot, many animals will aestivate, which is similar to hibernating, but is usually in response to a lack of water rather than a lack of food. The spadefoot toad spends 10-11 months out of the year buried in the soil, only to emerge to breed and feed during summer rainstorms.

So, while at first glance, it may look like there isn’t much life in the desert, keep in mind that the vast array of adaptations help ensure the survival of a high diversity of plants and animals in such a harsh ecosystem.

For Wild About Utah, I’m Mark Larese-Casanova.

Credits:
Images: Courtesy US FWS images.fws.gov
Courtesy & Copyright Daniel D. Beck, Central Washington University
Text: Mark Larese-Casanova, Utah Master Naturalist Program at Utah State University Extension.

Additional Reading:

Utah’s Desert Dwellers: Living in a Land of Climate Extremes. Wildlife Review. Utah Division of Wildlife Resources
wildlife.utah.gov/wr/0706desert/0706desert.pdf

Deserts. James MacMahon. The Audubon Society Nature guides. 1985. https://www.amazon.com/Deserts-National-Audubon-Society-Nature/dp/0394731395

Natural History of the Colorado Plateau and Great Basin, Harper, St. Clair, Thorne, and Hess (Eds.), 1994. https://www.amazon.com/Natural-History-Colorado-Plateau-Great/dp/0870815113

The Biology of Deserts, David Ward, Oxford University Press, 2009. https://www.amazon.com/Biology-Deserts-Habitats/dp/0199211477