Bighorn sheep (Ovis canadensis) taking a break on the grassy slopes of the National Bison Range, near Dixon, Montana. They were resting about twenty feet from our car and did not seem to mind our quiet audience.
I don’t think I’ve put this on tumblr yet, so here goes. This was my final from Drawing for Scientific Illustration, which I took this past winter. It’s an isometric paraline drawing of a bighorn sheep skull. If you have no idea what that means, click the image to see the process (animated!), the orthographics, and a photo of my specimen (who now lives on the bathroom counter and surprises our guests). It was done in conté on vellum, and took for-frickin-ever. It is featured in the student works show at the Guild of Natural Science Illustrators 2012 conference.
Here’s a room I’ve never posted about before – the Skull/Sheep room, where we keep the majority of our Ovis skulls and full skeletons. The UMZM has an extensive collection of these special bovids, the majority belonging to bighorn sheep (Ovis canadensis), but we also have a few specimens of Dall sheep (Ovis dalli) and a few domestics (Ovis aries). The huge curls on the trophy mount belong to Ovis ammon, the argali or mountain sheep, which is the largest of all wild sheep species and wanders the highlands of Asia.
I think the main reason I’ve never posted photos of this room before is because the storage practices are so unintentionally terrible. We do everything we can to ensure longevity of our specimens, however, the overcrowding has gotten obscene in that room. It flooded a few years ago and you can see the blue boxes are still sagging from the damage! Someday, hopefully sooner than later, we will be granted adequate space to spread out these skulls and discontinue the real-world Jenga game we’re forced to play in there every day. Until then, these literally are the skeletons in our closet.
Bighorn sheep (Ovis canadensis), seen on my morning walk in in Phoenix, Arizona.
These sheep are actually denizens of the Phoenix Zoo, in Papago Park. Geologically, the park comprises a grouping of sandstone monadnocks - isolated hills of red rock that rise abruptly from the surrounding terrain. The zoo has built its bighorn enclosure on the side of the southernmost hill - visible from the park’s trails, and a pleasant surprise for the urban hiker.
I mentioned on Monday that a few of the forensic anthropology students are working with Dave and I to put together a presentation for the Paleopathology Conference in Tennessee for next April. They are focusing on mandibular osteomyelitis (osteo = bone, myelo = marrow, itis = inflammation), or “lumpy jaw”, which is an infection caused by a bacteria of the Actinomyces species and can lead to severe dental abscesses, and tooth and bone loss and decay. Although this bacteria can live naturally within the saliva, lungs, and liver of a variety of bovines, it will infect the bone if given a way into the tissue, such as by way of previous trauma or infection but most commonly by severe dental impactions of plant matter. While we don’t have tissue samples to test for the bacteria itself, we are attempting to come up with data from our collection relying on evidence in the skeletal remains of our bighorn sheep. One of the articles I have been looking at (Source 3 below) mentions that horn development in males can be impacted by the infection, which would explain the massively enlarged cranium of the young adult male in the top pictures. You can see the gigantic, gaping hole in the right side of its mandible in the third picture.
If I could go to school indefinitely, my next degree would be as a veterinary pathologist specializing in wild animals. How awesome would that be?!
The Dall sheep (originally Dall’s sheep), is a species of sheep native to northwestern North America.
The sheep inhabit the mountain ranges of Alaska and Western Canada. Dall sheep are found in relatively dry country and try to stay in a special combination of open alpine ridges, meadows, and steep slopes with extremely rugged ground in the immediate vicinity, to allow escape from predators that cannot travel quickly through such terrain.
Male Dall sheep have thick curling horns. The females have shorter, slender, slightly curved horns. Males live in bands which seldom associate with female groups except during the mating season in late November and early December. Lambs are born in May.
During the summer when food is abundant, the sheep eat a wide variety of plants. The winter diet is more limited, and consists primarily of dry, frozen grass and sedge stems available when snow is blown off, lichen and moss. Many Dall sheep populations visit mineral licks during the spring, and travel many miles to eat the soil around the licks.
The primary predators of Dall Sheep are wolves, coyotes, black bears, and grizzly bears; golden eagles are predators of the young.
One of the graduate students in our Vertebrate Osteology class is writing her term paper on determining age based off of skeletal remains, comparing human bones to those of the bighorn sheep (Ovis canadensis). While we were going through the collection looking for comparative specimens with known ages, we found this male that was a remarkable 9 years old when it died, making it our oldest known sheep in the collection. Some of that severe aging is obvious in different parts of his skeleton, such as the large double abscesses in his molars and the subsequent infection of the mandible, the reduced gumline on the incisors, the arthritis in the vertebrae and sternum, and a weird growth on the ventral side of some of his vertebrae. I always get kind of excited when we come across these unique pathologies, as it reminds me of the individuality of the wildlife around us.