Bovine Ruminations - 10- Bc Blog Teacher

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22 Mayıs 2012 Salı

Bovine Ruminations

On a recent 10-day, two-part camping trip to the Carrizo Plain and East Mojave, we had the fortune of seeing a couple of uncommon ruminant species in CA - Pronghorn and Bighorn.

And both herds nicely hung out within zoom range.

pronghorn
Male pronghorn, Antilocapra americana, on the Carrizo Plain. Like cattle and bighorn sheep, pronghorn have permanent horns, not seasonally-shed bony antlers. And, also like bighorn and many cattle, the females have them too

moving the harem
Male moving his "harem" of 5 ladies

moving the harem
To keep them where he wants to forage

pronghorn
Female and male watching us watch them - "see - if we just stand around and look cute, they keep planting all this tasty barley"

Pronghorn and bighorn used to be our only remaining native Bovines in CA. But even though they have 4-compartment stomachs, cloven hooves, and horns, biologists re-classified the pronghorn, deciding that it was a bit too different to be a true bovine. Their branching and sheath-shedding horns, for example, are unique to the species - no other bovine has those features. So now each are the last of their California kind.

But the question I hear most about pronghorn is: "are they antelope?"

The answer is not really. That's just a name given to them because they look like African antelope, and fulfill a similar niche (good old convergent evolution in action). While they are in the same Order as antelope and gazelles, Artiodactyla (even-toed hoofed animals), that high-level grouping also includes deer, cattle, pigs, sheep, camels, hippos and giraffes. So, saying they're "antelope" is the equivalent to saying they're moose, or giraffes. In fact, African giraffes appear to be the nearest genetic relative to pronghorn, which is the only living member of the 12 species of Antilocapridae (antelope-like) that have roamed North America in the last million years.

The re-introduced population on the Carrizo Plain certainly isn't doing great. With less than 100 total individuals, their numbers are stagnant at best, and they often lose ground in tough years. Fragmenting of native grazing lands seems to be the top inhibitor. And domestic animal-borne diseases. Evolved roaming the large arid ranges of the west to find the shrubs & forage they need, developments and fences (they're notoriously poor jumpers) are boxing them into areas too small to sustain growth. Except in eastern CA, where the land is still big - there's thousands. Of course, the fact we ate the other 490,000 that lived in pre-1800 CA has to be the biggest limiter.

Some bighorn sheep populations in the expanses on the east side of CA are doing ok too, such as the Desert Bighorn of the Mojave area, Ovis canadensis nelsoni. The numbers of this subspecies are up to around 4,000 individuals in southern CA. Unfortunately, their cousins, the Sierra Bighorn, Ovis canadensis sierrae, aren't faring as well. Hence the collaring of kitties to help protect them.

We happened on ~ 20 Desert Bighorn while visiting the infamous Zzyzx. Evidently, the bighorn like to come down to the area for water in drought years. I guess for them, Lake Tuendae and the soda springs existed long before the spa town was built on top of it. Dang inconvenient humans.

bighorn ewe and lamb
Ewe and lamb Desert Bighorn Sheep, Ovis canadensis nelsoni, near Zzyzx

bighorn!
The herd - all ewes and young. Like many hoofed animals, the males generally hang out separate or in small groups when it's not mating season

bighorn ewes
Bighorn, like pronghorn, are versatile vegetarians, and can both graze and browse - eating grasses, forbs, cacti, and even the leaves of tough perennial trees and shrubs, such as the creosote and salt bush around these four ewes

bighorn
Ladies giving us one last look as we left

Pronghorn and Bighorn. Always a treat to see.

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