Category: Mammals

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Hearts

Hearts abound this time of year – gracing cards, storefronts, and of course, chocolates. And while the heart symbol bears little resemblance to the organ itself, their abundance of late has caused me to consider my own heart, beating away largely unacknowledged all these years.

In its simplest form, the heart is a pump. Its sole function is to keep the blood in your body on the move, partnering with your lungs to deliver life-giving oxygen to each and every hard-working cell, from the top of your head to the tip of your pinky toe. Most hearts have two distinct features – an atrium where blood collects on its way into the heart and a ventricle which pumps the blood back out.

But even with these shared components, not all hearts are alike. Throughout the animal kingdom, hearts take on a variety of forms. Fish, for example, have a two-chambered heart: one atrium that collects blood and one ventricle that pumps it back out. Blood journeys from the heart to the gills, where it picks up oxygen and then continues on its way, delivering its cargo to the body before making its way back.

Amphibians and reptiles, with the exception of the crocodile, have a three-chambered heart consisting of two atria and one ventricle. One atrium is designated for the oxygen-poor blood that is headed towards the lungs while the other is reserved for oxygen-rich blood coming back from the lungs and headed out into the rest of the body. In the shared ventricle, blood from both atria mix slightly, resulting in a somewhat inefficient system that nonetheless seems to meet the needs of the animals it serves.

Mammals and birds have taken the heart one evolutionary step further with the development of a four chambered heart that fully separates oxygenated and deoxygenated blood. Blood flowing in from the lungs enters the left atria and is pumped out to the body by the left ventricle, while blood returning from the body enters the right atria and is pumped to the lungs via the right ventricle. Because of this total separation, the blood leaving a mammal’s heart contains more oxygen than a reptile’s – a huge metabolic advantage that helps support our warm-blooded fast-paced lifestyle.

Two-, three- and four-chambered hearts are considered closed circulatory systems, meaning the fluid, or blood, is fully enclosed within blood vessels. Insects, on the other hand, have an open circulatory system which means that they don’t have blood vessels at all. Instead their bodies are simply full of fluid that is continually circulated with the help of multiple simple hearts that pass liquid through as they contract and relax.

Lastly, there are some organisms that don’t need hearts at all! These creatures absorb oxygen through their skin and are small or thin enough that oxygen easily diffuses to all parts of the body. Some jellyfish, for example, have a body wall only two cells thick that separates their internal body space from the water around them.

Without our comparatively complex hearts, we probably wouldn’t be able to do what we do as humans and mammals. So take a moment during this Valentine’s season to acknowledge your amazing heart. Throughout the course of your lifetime it will beat upwards of 2 billion times and will pump as much as 100 million gallons of blood through its chambers. A pretty amazing feat for something we only celebrate once a year.

For the Stokes Nature Center and Wild About Utah, this is Andrea Liberatore.

Credits:
Text:     Andrea Liberatore, Stokes Nature Center in Logan Canyon.

Additional Reading:

Campbell, N.A. (1996) Biology, Fourth Edition. Benjamin/Cummings Publishing Company, Menlo Park CA

Bailey, Regina (2013) Circulatory System: Types of Circulatory Systems. https://biology.about.com/od/organsystems/a/circulatorysystem.htm

Meyer, J.R. (2005) Insect Physiology: Circulatory System. North Carolina State University. https://www.cals.ncsu.edu/course/ent425/tutorial/circulatory.html

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Tracking Wildlife in Winter

Jumping Mouse Tracks
Photo Courtesy & Copyright 2011
Mark Larese-Casanova

Moose Tracks in Snow
Photo Courtesy & Copyright 2011
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

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Mule Deer

Mule Deer Herd
Odocoileus hemionus
Photo Courtesy US FWS

Mule Deer Herd
Odocoileus hemionus
Photo Courtesy US FWS
Gary Zahm, Photographer

Mule Deer Herd
Odocoileus hemionus
Photo Courtesy US FWS
David Heffernan, Photographer

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

It’s that time of year again, the leaves have fallen from the trees, the snowy holidays are on their way, and love is in the air for one of Utah’s vital wildlife species. Odocoileus hemionus, commonly known as Mule Deer are the smallest members of the Cervid family in Utah, after moose and elk. Their name is derived from their large ears which resemble those of a mule.

Mule deer have a coat that ranges from dark grey, to a lighter tan color, a white rump patch, and tail with a black tip.

In the months of November and December Mule deer are active in their breeding season known as the rut. During the summer and early fall males will typically live away from does and fawns, and begin to “play” fight with other males to establish a hierarchy of dominance. Once the rut begins males will seek out does, and become more aggressive and compete with one another for females to breed with. The less dominant males are usually aware of their status, and will be chased away by larger bucks. However males that are similar in size will posture to one another, lock antlers and fight to establish breeding rights with the doe.

Mule deer are not monogamous in nature. Males will breed with any female that will accept them. Does can also breed with multiple bucks, providing the possibility of multiple births from different fathers. The receptive period for does is known as estrus, and typically lasts for less than a day, and sometimes only a few hours. If the first estrus cycle is missed does can go through another cycle in about four weeks. When the rut comes to an end, bucks will return to being solitary until they shed their antlers in late winter.

In Utah, does typically give birth in June and will leave the herd to be alone. The older does commonly have twins, while younger does have only one fawn. After the fawns are born the cycle of life starts again.

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

Credits:

Images: Courtesy US FWS, Gary Zahn and David Heffernan, Photographers
Text:     Mary Jackson, Justin Hicken, Utah State University

Additional Reading:

LEARN MORE, Find out more about mule deer and what the DWR is doing to help them, Utah Division of Wildlife Resources, Department of Natural Resources, State of Utah, https://wildlife.utah.gov/16-wildlife.html?start=14

Ongoing Efforts to Help Utah’s Deer Herds, Utah Division of Wildlife Resources, Department of Natural Resources, State of Utah, https://wildlife.utah.gov/md-help.html

Mule Deer Statewide Management Plan, Utah Division of Wildlife Resources, Department of Natural Resources, State of Utah, https://wildlife.utah.gov/pdf/bg/mule_deer_plan.pdf

Mule Deer, Utah Species, Utah Division of Wildlife Resources, Department of Natural Resources, State of Utah, https://fieldguide.wildlife.utah.gov/?species=odocoileus%20hemionus

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Tales of the Packrat: The Legacy of Early Grazing on Utah’s Rangelands

Legacy of Early Grazing on Utah's Rangelands: Pack Rat Midden, Photo Courtesy and Copyright 2009 Ken Cole - All Rights Reserved
Pack Rat Midden
Copyright © 2009 Ken Cole

Reaching for a Pack Rat Midden, Click to Zoom, Photo Courtesy and Copyright 2009 Ken Cole - All Rights Reserved Reaching for a Pack Rat Midden
Copyright © 2009 Ken Cole

One of the best storytellers in Utah’s national parks is not a ranger, but the lowly packrat.The Legacy of Early Grazing on Utah’s Rangelands
Their stories of past plant communities are written in their middens. The midden is a heap of leaves, twigs, seeds and fruits the packrat discards outside its nest. Protected in a desert cave or rock crevice and preserved by a rat’s own urine, this heap is a detailed and accurate time capsule of the past local flora.

Ken Cole with the US Geological Survey is a fluent translator of the packrat’s stories. Ken and colleagues sampled old packrat nests around Glen Canyon National Recreation Area and Capitol Reef National Park. By carbon-14 dating, the nest ages are known to span the last 10,000 years. As controls, they also collected nests from mesa tops inaccessible to livestock. Ken and colleagues then carefully translated these packrats’ stories by identifying and counting the plant fragments in these fossil nests.

At both Capitol Reef and Glen Canyon, old packrat nests revealed pre-settlement plant communities that were rich in diverse grasses, wildflowers and shrubs. Then these floras changed. Beginning 150 years ago, vast herds of sheep and cattle tromped and chewed their way across the unfenced rangelands of Utah in numbers unimaginable today. We know that palatable plant species and those susceptible to trampling suffered declines, because they are absent from middens from that time period. Unpalatable shrubs multiplied. Despite curtailed grazing in subsequent decades at Capitol Reef and Glen Canyon, packrats show us that the flora still has not recovered. Like Aesop’s fables, this cautionary lesson of the packrat’s ecological tale remains clear and relevant today. We should all listen.

This is Linda Kervin for Bridgerland Audubon Society.
The Legacy of Early Grazing on Utah’s Rangelands
Credits:

Photos: Courtesy and Copyright Ken Cole
Text: Julio Betancourt USGS and Jim Cane, Bridgerland Audubon

Additional Reading:

Betancourt, Julio L., Thomas R. Van Devender, and Paul S. Martin, eds. Packrat Middens: The Last 40,000 Years of Biotic Change, University of Arizona Press, 1990 https://www.uapress.arizona.edu/books/BID40.htm

Pack Rat Middens, Colorado Plateau in Land Use History of North America, Ken Cole, USGS/Northern Arizona University, https://cpluhna.nau.edu/Tools/packrat_middens.htm

Introduction [to Carbon 14 Dating], Tom Higham, Radiocarbon Laboratory, University of Waikato, New Zealand https://www.c14dating.com/int.html [Sep 24, 2009]