Wolves and Bears, Oh My!

Rain threatened all morning, then class in the evening, so here's a couple of zoo shots:

Red Wolf (Canis rufus), Henry Doorley Zoo, Springfield, IL 5/21/2013

This is a Red Wolf (Canis rufus).

Mexican Gray Wolf (C. lupus baileyi), Cheyenne Mountain Zoo, Colorado Springs, CO 12/27/2013

This is a Mexican Gray Wolf (C. lupus baileyi).

At various times, the Red Wolf has been considered a subspecies of the Gray Wolf (thus C. lupus rufus) (1) and a hybrid of Coyotes (C. latrans) and Eastern Gray Wolves (C. lupus lycaon) (2, 3). (It's been argued that Eastern Gray Wolves aren't properly placed in C. lupus, (4) as well.) This is all a rather obscure academic dispute, I suppose. Even most people who care that there are wolves in the US don't know the ins and outs of their relationships. Except for one thing -- Red Wolves are a critically endangered species, with a re-introduced population living on Alligator River NWR in northeastern North Carolina. If they were indeed to be considered a subspecies of the Gray Wolf, the reintroduction program might itself be endangered. Trying to do science well is hard enough. Trying to do it well with this sort of controversy lurking behind every abstract must be a bit of a nightmare.

Here's another couple of critters with similar histories:

Alaskan Brown Bear (Ursus arctos alascensis), Alaska Zoo, Anchorage, AK 8/12/2012

Grizzly Bear (U. arctos horribilis), Cheyenne Mountain Zoo, 12/27/2013

These are both Brown Bears (Ursus arctos), although currently considered different subspecies. There have been quite a few different subspecies described, from as few as 5 to as many as 90! In the 1920's and 1930's, though, the Grizzly (Ursus horribilis) was still considered a separate species. (5) Again, since Grizzlies are listed as endangered, while Brown Bears as a whole aren't, these decisions actually matter. And here's an interesting question for the near future, along these lines:

Polar Bear (U. maritimus), Cincinnati Zoo, Cincinnati, OH 3/29/2012

This, of course, is a Polar Bear (Ursus maritimus). If you're into bears, you've probably heard of the Grolar Bears that have recently been shot in the Arctic reaches of North America. Those would be Ursus maritimus X arctos hybrids. Hybrids between species indicate that those species are closely related, and indeed research suggests divergence times as old as 5 million years (6) and as recent as
150,000 years. (7) While there is evidence from DNA of hybridization, and a couple of older specimens, recent discoveries of wild grolar bears has raised the specter of climate change pushing the two species into more contact, with grizzlies moving north as the climate warms and polar bears spending more time on land as the ice melts. If they are capable of hybridizing, and the hybrids are born into a changing world that favors a melding of the two species, could we see the recently evolved Polar Bear merging back into the Brown Bear they evolved from? And if so, what would we call the resulting population, and how would we deal with it in terms of conservation?

Science is all about trying to refine our view of the world. Often that requires a focus which nearly shuts out all but the little piece we're working on. But the rules our world plays by don't always allow the Ivory Tower approach -- the things we do really do make differences in the world around us.


(1) Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M. Mammal Species of the World (3rd ed.). Johns Hopkins University Press.
  
(2) VonHolt, BM; et al (12 May 2011). "A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids". Genome Res 21 (8): 1294–305. 

(3) Wayne, R. and S.Jenks. 1991. Mitochondrial DNA analysis supports extensive hybridization of the endangered red wolf (Canis rufus)" Nature 351:565-68.
 
(4) Chambers SM, Fain SR, Fazio B, Amaral M (2012). "An account of the taxonomy of North American wolves from morphological and genetic analyses". North American Fauna 77: 1–67. 

(5) Baggley, G. F. (1936). Status and distribution of the grizzly bear (Ursus horribilis) in the United States. In Transactions of the North American Wildlife Conference (Vol. 1, pp. 646-652).

 

(6) Miller W, Schuster SC, Welch AJ, et al. (July 2012). "Polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change". Proc Natl Acad Sci U S A 109 (36): E2382–90.

 

(7) Lindqvist, Charlotte; Schuster, Stephan C.; Sun, Yazhou; Talbot, Sandra L.; Qi, Ji; Ratan, Aakrosh; Tomsho, Lynn P.; Kasson, Lindsay et al. (2010). "Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear". Proceedings of the National Academy of Sciences 107 (11): 5053–5057.