Humans have a peculiar knack for naming animals based on their doppelgangers instead of their biology. Take sea horses, for instance. These bizarre fish haven't a hoof or mane to speak of. But their angular, elongated faces resemble their equine namesakes. You'll find similar misnomers for other animals, such as koala bears, Komodo dragons and mountain goats.
Mountain goats sport the woolly coats, cloven feet and horns comparable to those on true goats (members of the goat family). Males and females are even referred to as billies and nannies, respectively. But in the same way that mountain lions aren't lions at all, mountain goats aren't classified in the same group of species as true goats. And understanding the differences between those three physical traits (coat, hooves and horns) tells us a lot about how exactly the mountain goat species stands out.
The most obvious distinction between mountain goats and true goats is habitat. Between 40,000 and 100,000 mountain goats dwell in North America, residing among mountain peaks and crags from the northern Rockies to south central Alaska [source: Festa-Bianchet and Cote]. Their high-altitude homes call for thicker, shaggier fur than their domesticated counterparts. Two types of woolly fur cover and insulate mountain goats from the cold. A shorter coat of inner fur sits close to their skin. Guard hairs, which might extend up to 8 inches (20 centimeters), then create their shaggy appearance. Those guard hairs have a hollow structure, which traps frosty air before it can penetrate the skin [source: Chadwick].
In order to survive such precarious terrain, mountain goats have specialized hooves suited for climbing as well as descending treacherous slopes. Mountain goats have split hooves that they can spread out or contract for stability. Rubbery padding covering the bottoms of their hooves provides additional traction. This anatomical feature serves as an important survival tool since the landscape is a mountain goat's most pertinent threat. Mountain goat predators such as cougars or bald eagles may steal into their lofty territory, but more die from falling due to snowdrifts, avalanches and rock slides [source: Burton and Burton].
Yet the mountain goats' crowning features -- two pointy horns -- separate them genetically the most from true goats.
Mountain Goat Species and True Goats
What constitutes a true goat? In order to be considered a true goat, an animal must be a member of the genus Capra. That group includes species of domesticated goat, wild goats and ibexes (European mountain-dwelling goats). North American mountain goats, however, are the sole species of the genus Oreamnos. Yet the translation of the Latin genus name doesn't give us much of a hint regarding the difference between mountain goats and true goats. Oreamnos literally means "mountain lamb," which also misinforms since the goats aren't a sheep species, either.
If you look up the definition of mountain goat, you'll usually find the word "goatlike" in the text. Other descriptions refer to them as genetic crosses between true goats and antelopes, or goat-antelopes. However, molecular studies also have linked mountain goats to musk oxen [source: Festa-Bianchet and Cote]. Most likely, mountain goats share a common ancestor with true goats and sheep [source: Chadwick].
Anatomically, goats and mountain goats aren't terribly different from each other. In fact, you have to dig fairly deep to discover the primary distinction between the two animals. For mountain goats and true goats, it boils down to bone. First, mountain goats have thinner, lighter skulls than true goats [source: Chadwick]. Also, their horns, which are made from keratin protein, are a different shape. Curving slightly back toward their heads, mountain goat horns grow shorter, slenderer and pointier than those of true goats. Male mountain goats benefit from the relatively smaller horns. In spring when the males go into rut (or enter mating season), they don't fight as aggressively to win the females. For that reason, larger horns would be unnecessary, although mountain goats can still inflict some damage to competing goats with their horns.
They share those skeletal characteristics with a tribe, or group, of bovine species called rupicaprids. Rupicaprids are a subset of the animal family Caprinae, which includes oxen, sheep and true goats. Mountain goats are the only rupicaprids in North America. Their predecessors crossed over the Beringia land bridge from Asia 40,000 years ago [source: Festa-Bianchet and Cote]. Five species comprise the tribe: goral, serow, Japanese serow, chamois and mountain goat. Each looks quite different from one another, except for the signature horns, described above.
The mountain goat's name isn't entirely off the mark -- especially when to compared to that of the sea horse. Scientifically, it doesn't pass the accuracy test. But at least it's all in the family.
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More Great Links
- Burton, Maurice and Burton, Robert. "International Wildlife Encyclopedia." Marshall Cavendish. 2002. (Dec. 15, 2008)http://books.google.com/books?id=4QQCfJnu_6oC
- Chadwick, Douglas H. "A Beast the Color of Winter." University of Nebraska Press. 2002. (Dec. 15, 2008)http://books.google.com/books?id=SMnXTHE5iWMC
- Festa-Bianchet, Marco and Cote, Steeve D. "Mountain Goats." Island Press. 2008. (Dec. 15, 2008)http://books.google.com/books?id=v1FeioiEdIgC
- Johnson, Loyal J. "Mountain Goat." Alaska Department of Fish & Game. 1994. (Dec. 15, 2008)http://www.adfg.state.ak.us/pubs/notebook/biggame/mtn_goat.php
- Shackleton, David M. and Cowan, Ian McTaggert. "Hoofed Mammals of British Columbia." UBC Press. 1999. (Dec. 15, 2008)http://books.google.com/books?id=iQq2iFktrwoC
- Wilson, Don E. and Ruff, Susan. "The Smithsonian Book of North American Mammals." UBC Press. 1999. (Dec. 15, 2008)http://books.google.com/books?id=qNFgzIPGuSUC