Showing posts with label mammals. Show all posts
Showing posts with label mammals. Show all posts

Tuesday, September 24, 2013

American bison

The American bison (Bison bison), also call buffalos (even though very... very distantly related to true buffalo), are often known as the face of the American west. They are one of the few species in North America that are both raised in captivity (not domestic) for their meat and roam in wild herds. Bison can grow to massive sizes, with wild individuals reaching 700 to 2,200 pounds and captive individuals reaching upwards to 3,800 pounds. Males tend to be slightly larger than females.


American bison in Yellowstone National Park
Photo by: Matt Brincka

The American bison roam the plains, sagebrush and lightly wooded areas of the mid-western and western North America. They are migratory, traveling between foraging sites. On average, a herd's daily routine consists of foraging and chewing cud for roughly two hours then traveling to the next site. Sometimes, this traveling can amount to around 2 miles per day. Similar to other herd animals, females live is maternal heard consisting of other females, juveniles, and sometimes elderly males. Males will often leave the materinal herds when they are around three years of age, joining other males in bachelor herds (parrrrtaaay). During the breeding season, males will gather females into a small harem for mating. These bulls will ward off other males who get too close.

American bison often use man made roads as route of easy travel... often delaying traffic.
Photo by: Matt Brincka

Bison partake in a variety of interesting behaviors. During the fall, herds usually wander into more forested areas, preparing for the winter months. at this time, bison partake in a behavior where their rub their horns against aromatic trees, saplings and even utility poles. The tree release an aroma after being horned which is connected providing a deterrent against biting insects. Bison also participate in a wallowing behavior, where they wallow, or roll, in a shallow depression of soil. There are many hypotheses as to why bison wallow, including shedding, rutting, group cohesion, play, scratching their insect bites, removing of ticks, and to keep cool.

Locking horns
Photo by: Matt Brincka

When Columbus first step foot in the New World, there were an estimated 60,000,000 (yes... 60 million) American bison that roamed in herds as far as the eye could see. Many native plain cultures based their societies around the American bison, traveling with the herds, utilizing every part of the animal. When European settlers came, all did not bode well for our friendly, roaming plain goliath. Bison hunting turned into a continent wide cull. In the 1800s, western expansion was in full swing and it has been told that men would sit on the top of trains and shoot the bison herds as they passed. The option to shoot buffalo was often provided by train companies to tourists because they wanted the herds culled. A single bison herd could delay a train for days. The main reason of the American bison decline was because the US Army actively endorsed the wholesale slaughter of the herds. Hunters would shoot hundreds of buffalo at a time, skinning them, allowing the meat to rot, then shipping the bones back east. The federal government had multiple reasons to promote the mass cull of bison, but it is said it was mainly to allow ranchers to range their cattle without competition from the herds and (the probable real reason) to weaken the North American Indian population by removing their main food source.

Wallowing in a dust hole
Photo by: Matt Brincka

Interesting Tid-Bits
  • Sometimes bison give birth to a white juvenile, which are of spiritual significance to Native American culture
  • Several American coins have featured the bison, including the "buffalo nickel" from 1913 to 1938.
  • The city of Buffalo, NY originally was called New Amsterdam and resided on Buffalo Creek.... and yes, New York City was originally named New Amsterdam by Dutch explorers. Well guess what, it was a Holland Land Company that first established the Buffalo - New Amsterdam. Residents of New Amsterdam (Buffalo) didn't like the name much, so in 1808 they renamed their town as the "Village of Buffalo". There are a few theories as to why the village was renamed Buffalo, and it is often disputed. One is it related to a story that stolen horse meat was being passed off as bison flesh, with the area then remembered as "Buffalo," however, there is great skepticism towards this. Another is that the name "Buffalo" is a horrible butchering of the French saying beau fleuve meaning "beautiful river," which was used to describe the Niagara River. Another is that the town was named after Fort Le Boeuf, translated as "Fort Buffalo," but this fort ceased operation years before the settlement of New Amsterdam. All of these theories stem from the belief that the American bison once roamed Western New York, but there are only 1 or 2 historical accounts, which aren't 100% reliable. It is also widely accepted that if bison roamed Western New York, they were extirpated years before colonists made it there. Many believe it is the legend of the American bison that fueled the naming. However, without more historical discoveries that creates an indisputable generation story, the naming of Buffalo, and Buffalo Creek, will forever be debated.


Sunday, July 7, 2013

Rocky Mountain Goats

Mountain goats grazing on alpine vegetation

Goat? Nay. Not even close actually. The mountain goat (Oreamnos americanus), also know as the Rocky Mountain goat, is actually a member of the antelope family. Yup, "home on the range" antelopes. This large-hoofed mammal is only found in the subalpine to alpine zones of western mountain ranges in North America. Predators aren't a problem due to extreme alpine conditions during the winter, but they have to be wary when the snow melts. Thanks to sure-footedness from pliable hooves with rubbery pads and muscular forequarters, these mountain champions can conquer craggy rock surfaces where predators cannot follow. More mountain goats actually die from avalanches and rockslides than predation. Being herbivores, they spend most of their time grazing herbs, grasses, lichen, sedges, ferns, mosses, twigs and leaves. A double layer fur coat helps it survive extreme cold temperatures at high elevation over winter, with the overcoat molting and falling off during warming months.

Mountain goats typically live in herds, which they change seasonally after mating. Nannies (females goats) tend to herd together for most of the year with their kids (yes, baby mountain goats are called kids), while males, known as billies, either go lone-wolf or travel in groups of 2 or 3. In summer, herds tend to be smaller and travel between salt licks and water sources. Nannies can be extremely territorial, fighting other nannies within the herd over food.

A nanny with her twinnies

Nannies in a herd typically undergo synchronized estrus in October to December, which means they all go into "heat" at the same time and are ready to mate. Knowing sexy-time is around the corner, mature males join the female herds at this time. Males often go through mating rituals that includes staring at the females (I mean, who doesn't), digging ruts in the ground with their hooves and showy fights with other males, often involving locking horns. Both males and females are highly promiscuous and will mate with multiple individuals over the course of the entire mating season. However, males will often try to fend off other males from mating with females they've already mated with.

Gestation takes around 150 to 180 days, or 5 to 6 months. After separating itself from the herd, a nanny typically gives birth to a single kid, with twins (called twinnies) typically a rarity. After birth, kids are expected to get on their feet within a few hours before the nanny heads back to the herd. Kids stay with their for about a month, with some staying as long as till the next breeding season. If the kid is still around by the following breeding season, the mother will chase it away. When observing a herd, one can often see kids playing and jumping around with each other.

Month old twinnies resting at midday

Interesting tid-bits
  • After the age of 22 months, you can tell how old a mountain goat is by counting the number of rings on its horns
  • Can jump nearly 12 feet in a single bound.
  • Both males and females have horns.
  • Both sexes are not sexually mature till 30 months, old compared to other hoofed megafauna.
  • Eagles may occasionally try to chase a kid off of a cliff for a meal.