Species of the Month

Up on the rooftop click click click, down through the chimney it's the species of the month! Christmas is right around the corner, so it’s time for another festive species of the month. The caribou is the wild version of the domesticated reindeer. Santa’s herd is safe, but their wild counterparts face habitat loss and in some areas have been hunted to extinction.

Woodland caribou

Scientific name: Rangifer tarandus

Kingdom: Animalia (animals)

Class: Mammalia (mammals)

Order: Artiodactyla (even-toed ungulates)

Range: Circumpolar- Canada, northwestern US, Greenland, northern Europe

Habitat: Arctic tundra and boreal forest

Lifespan: 4.5 years on average

Diet: Leaves, bark, lichen, mushrooms

Predators: Bears and wolves

Conservation Status: Endangered (US), IUCN Species of Least Concern

Lighter colored tundra caribou (NPS)

Other Information: Caribou are the only deer species featuring antlered females. Not all females grow antlers, however. Male antlers are larger and more intricate. Males use theirs in sparring during the rut. Like other deer species, mating is controlled by a dominant bull who fends of younger challengers. The fights leave males injured and/or exhausted and vulnerable to predators. Domesticated reindeer have been used as beasts of burden and for food for thousands of years. There are several subspecies of caribou. Northern caribou are nearly white and smaller than their southern counterparts. In North America, the woodland caribou is a dark brown and critically endangered. Just a handful lived in the wild in Washington and Idaho. Recently, they were all captured and sent to a secure area in British Columbia to protect them from predators in the hopes that their population will increase. Caribou hooves are very large and concave, serving as snowshoes.

Caribou hoof (Where To Next)

The size and shape also aid in swimming. Caribou migrate long distances and must cross many rivers. When walking, they make a loud clicking sound, caused by a foot tendon rubbing on bone.

Information once again comes from the good people at Michigan’s AnimalDiversity Web.

Domestic reindeer (The Nature Conservancy)

A Christmas Comet

Just in time for the holidays Earth has a celestial visitor! Comet Wirtanen makes one of the closest approaches ever recorded. It’s a small comet with a short orbital period of 5-6 years. It is bright enough to see with the naked eye, although because of its small size the way it scatters light, it is hard to spot. Keeping with the holiday tradition, if you’re lucky enough to see it, it will appear to be green.

Wirtanen approaches, as seen in November (NASA)

I am sadly surrounded by street lights, so I had to take a short trip to a state park where I had a dark sky. With a spotting scope and a general area of where to look, I was unable to find Wirtanen. The comet makes its closest approach to the sun tonight, and I decided to try again. However, I’ve been blessed with clouds. My next chance is Saturday night, when it is closest to Earth. Of course, rain is in the forecast.

Geminids (Smithsonian Magazine)

While I failed in my attempt to see just my second comet, I happened to see a meteor streak across the sky. Meteor showers are bits of cometary debris burning up in the atmosphere as Earth passes through the comet’s debris field. Comets are just dirty snowballs that melt a little bit as they approach the sun. As they break up, all the pieces that break off trail behind and wait for our orbit to sweep them up. This meteor was not associated with Wirtanen. It was part of the Geminid meteor shower, which is debris from the comet 3200 Phaethon, a dead comet. Its ice has melted and all that remains is rock. Most likely, if we ever pick up all the debris then there will be no more Geminids.

If you want to try your luck at finding Wirtanen, here’s a handy link that shows its location throughout the month. This month's information is from StarDate and NASA.