Napping Bears and Frustrating Hyraxes

Marie got a break today. She is the resident grizzly bear. We were going to do her annual physical today, but that was postponed. As part of the renovation of the Mutual of Omaha’s Wild Kingdom Pavillion, there are going to be animal tracks of several of the animals that live at the zoo. One of the reasons we were going to do her physical today was because the guy who makes the footprints was going to be able to be here. However, the weather had other ideas. It will probably be done sometime in the near future when he is able to come out. So, Marie, you can continue snoozing on your log!

The majority of the rest of the day was spent dealing with the hyrax. There is some disease sweeping through them, though we are not sure yet what it is. We anesthetized 6 of them today to do more thorough examinations and collect samples for analysis and it is our hope that we can get an answer. We have a strong theory as to what it is, and – hopefully – the results from the lab will confirm it.

I’ll take a moment to talk about hyrax. They are very interesting creatures. When you look at them, you’d think they would be some sort of rodent, perhaps something along the lines of a musk rat or even a prairie dog. In fact, hyraxes are so unique, they have their own Order (Hyracoidea) of classification, of which they are the only members (family: Procaviidae). There are several species of hyrax (genus Procavia = rock hyrax (4 species), genus Heterohyrax = bush hyrax (1 species), and genus Dendrodyrax = tree hyrax (3 species)) but they have no close relation with other species. In veterinary medicine – particularly zoo medicine – you count on some simularities between species to help you get by. Tiger physiology is comparable to domestic cat physiology, and we see a lot of the same problems in both so there is some research to fall back on. Domestic cattle and gaur are, likewise, fairly similar on the inside in many respects. Zebras are kind of like horses. You can dose a bear on a similar mg/kg (miligram drug per kilogram bodyweight) ratio as you do a dog. But hyrax don’t even have a 2nd cousin twice removed to compare them to. Interestingly enough, their closest relation is the:

Yeah, no kidding. Apparently, elephants and hyrax (along with manatees) share a common ancestor, and that’s as close a relation as you’ll get with them. You can see where the problem comes in. It makes little sense to do much comparison between a ~2 lb furball and a 6000+ lb elephant.

So, what makes hyrax unique? Well, here’s a list:
- they have a pair of upper incisors that grow continuously – tusks!
- lower incisors are modified into fur-combing equipment
- no gallbladder (similar to horses and rats)
- highly complex digestive tract – 3 distinct microbial digestion areas
- 4 toes in front, 3 in back, all ending in hoof-like nails
- don’t thermoregulate well – they need to huddle together and sunbathe
- highly skilled climbers

In short, they are special little creatures. And I firmly hope we figure out what is wrong with them and how to help them out. I’ll keep you informed about the progress of this case. It may mean another great paper possibility!

I did some other things today as well, though nothing blog-worthy. So I will end with another cliff-dweller from Africa. This is a Klipspringer, a species of antelope. You’ll note his unique hoof structure which allows him to be very nimble on particularly steep, rocky terrain.