August 22, 2018 - Mammals

Updated: Sep 12, 2018


Mammals are a group of typically warm-blooded vertebrates that are covered in hair at some point during their development. Throughout the world there are species of mammals ranging in sizes from bats that weigh only a single gram up to the blue whale that is several tons in weight. A few features unique to mammals include:

1. Three middle ear bones transmit sound waves across the middle ear.

2. Female mammals feed their young from milk secreted from mammary glands.

3. The brains of a mammal include a neocortex which is involved in higher sensory perception.


The circle of life is represented in this week's featured four in that each of these represents either predator or prey for one or more of the others.


1. Groundhogs

The lowest on the food chain of the species featured this week is the Groundhog. Commonly heralded as springtime prognosticators, the folklore of groundhogs day suggests that the mid-winter emergence of these large rodents can actually predict an early spring or a continued winter. On February 2nd, the legend suggests that if the groundhog sees its shadow, the air will remain cold for six more weeks. If not, the weather will warm. There is no scientific basis for this myth but the festivities surrounding the day, the most famous being Punxsutawney Phil in Pennsylvania, have persisted for well over a century, originating in 1887.


A few interesting facts about the Groundhog:

1. These large rodents are surprisingly tidy, having dedicated rooms for waste, or bathroom chambers, in their complex underground burrows.

2. Woodchuck is another name for Groundhog. However, they do not chuck wood at all, although they will feed on tree bark. The name woodchuck is actually derived from the Native American name wuchak.

3. Another common name for groundhogs is whistlepigs because of their high pitched alarm call.

4. Groundhogs are the largest members of the sciurid, or squirrel, family. That's right, groundhogs are large squirrels.

5. Their diet is mainly herbivorous consisting of grasses and other vegetation but they will also eat berries and occasionally insects, grubbs, grasshoppers and other small animals.


Kelly Frederick Sweet photographed this young family that she found living under an empty house in her neighborhood for two years in a row.



2. Gray Fox


Next up is the Gray Fox, a common predator of rodents. Here are a few interesting fact about Gray foxes:

1. As you can see from the image below photographed by Elizabeth Traff, these small canids are hardy. Their natural range is from northern South America up to the southern regions of Canada.

2. Gray foxes are one of only two canid species, and the only one in North America, that climbs trees. Their specially hooked claws, much like a cat's, gives them the grip necessary for climbing.

3. These solitary hunters have a diverse, omnivorous diet ranging from small mammals, birds, reptiles, amphibians, insects, fruits and vegetation.

  • Because rodents are a part of a Fox's diet, it is important not to set out mouse or rat poison as it can indirectly be fatal to a fox as well as pets and other wildlife. Not only will the fox be harmed, it can also result in an increase in the rodent population by removal of their natural predators.

  • Because of their fruit ingestion, gray foxes are helpful in the distribution of seeds as they dispense them in their waste.

3. Preferring to live in deciduous forests, they can be found denning in abandoned burrows or hollowed tree trunks. Because of their climbing ability they can even make their dens high up in trees.

4. Although not currently threatened as a species, habitat loss and human encroachment have forced Gray Foxes to live closer to residential areas.

Fox on a bitter cold winter day photographed by Elizabeth Traff

3. Bighorm Ram


Although the largest of the mammals featured in this blog, Bighorn Rams are still not at the top of the food chain among these four. In fact, sheep are herbivorous and Coyotes are a threat to bighorn lambs. The Bighorn Ram is a male of a species of sheep specific to North America. Split into three sub-species, Rocky Mountain bighorns, Sierra Nevada bighorns and Desert Bighorn sheep, they are found in distinctly different ecosystems. However, there is some crossover, making it sometimes difficult to distinguish between the species.


Aptly named, the large horns of a mature male can weigh nearly 10% of its body weight. Rams can grow to nearly 350 pounds with their horns weighing up to 30 pounds. Also not surprising, they do use their horns to ram other males. Spending most of the year in bachelor groups with other rams, during the rut or mating season especially, these testosterone-filled males will engage in battles to establish dominance in the mating hierarchy.


It is possible to judge the age of a Bighorn Ram from the size of his horns. These permanent fixtures begin growing at birth and continue to gain mass throughout much of their lives. The annuli rings of a ram can be counted to determine its age. In the image below photographed by Gina Vaughan this male is younger than four years old because it hasn't grown its four-year ring.


Bighorn Ram in Rio Grande Gorge in New Mexico photographed by Gina Vaughan


4. Urban Coyotes


Finally, the Coyote is a predator for each species listed above. Having lost a large chunk of their habitat to human development, Coyotes have adapted and thrived in the most surprising urban locations. These very versatile canids continue to expand their territories further into urban areas. It's becoming increasingly common to find them even on city streets as they search for rodents. However, most often these canids have adapted a nocturnal lifestyle in avoidance of humans.


The Urban Coyote Initiative is a group of photographers, videographers and scientists dedicated to educating the community about these intelligent creatures and how we can peacefully coexist with them. Articles provided on their website discuss how to respond if you encounter a Coyote while outside with your pet. Although humans are not typically in danger from Coyotes, their small pets might be at risk.


Having a very flexible diet, Coyotes will feed on anything from deer and rodents to insects, reptiles, fruits, vegetables and carrion. Because coyotes feed on rodents their potential for illness due to poison is also high. And again, if left alone, Coyotes and Foxes will naturally control the number of rodents in your yard.


In these two images, Dave Barnes has photographed Coyotes that make their home near a golf course. Because they prey on the rodents that commonly infest the greens, Coyotes can actually be helpful to the landowners.

Coyotes can help maintain the rodent population at golf courses. Photograph by Dave Barnes.

Coyote Lounging in the Shade in the rough at a Phoenix, Arizona golf course. Photograph by Dave Barnes.

5. Resource Links


Mammals

neocortex

Punxsutawney Phil

Groundhog

Wuchak

Sciurid

Gray Fox

Dangers of poisoning rodents

Bighorn Rams

Desert Bighorn sheep

Judging the age of a bighorn ram by the size of his horns

Annuli

Rutting period

Urban Coyote Initiative

What to do if you encounter a Coyote while walking your dog



6. NHTL Workshop

Are you interested in growing your photography skills or learning natural history through your own lens? Come join us in September for our first ever Natural History through the Lens Photography Workshop series!  We are sold out for our inagural program but are keeping a mailing list for spring 2019. Send us your e-mail to be added to the list.



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