I’ll admit that I’m out of touch. Nobody told me there were dire wolves in George R. R. Martin’s Game of Thrones saga. Being too cheap for premium cable and too lazy to have read any of the books, I don’t know if Martin has other Pleistocene megafaunal species running around his fantasy landscape. Still, it’s nice to see Canis dirus enjoying its moment of celebrity.
Although best known as a victim of the Rancho La Brea tar pits, the dire wolf had an extensive range throughout the Americas. The type specimen came from Indiana, and others have turned up in caves in Arkansas and Missouri. The UC Museum of Paleontology has ten specimens from Irvington, near Fremont in southern Alameda County. Those remains were unearthed by a gang of “Boy Paleontologists,” aged 7 to 13, in the 1940s, along with early-model sabertooth cats (Dinoblastis, not the state fossil Smilodon), ground sloths, mammoths, horses, peccaries, camels, a four-horned pronghorn, and a sort of musk ox. Some of these creatures are on display at the Math Science Nucleus in Fremont (www.msnucleus.org/gordon/gordonhall.htm), although I can’t vouch for the dire wolf.
According to Dogs: Their Fossil Relatives and Evolutionary History by Xiaoming Wang and Richard Tedford, the dog family as such evolved in North America and colonized Eurasia by way of one of the recurrent Beringian land bridges. Early on in the glacial era, a large Chinese species, C. armbrusteri, retraced its ancestors’ steps. About a million years ago, armbrusteri give rise to dirus, which pretty much displaced it except in Florida.
Grateful Dead lyricist Robert Hunter to the contrary, no dire wolf ever approached 600 pounds. But dirus was a big dog, the largest wild member of the true canine lineage. Some of the earlier bone-cracking borophagine dogs, which were part of the Miocene Blackhawk Ranch fauna, were bigger. Dire wolves reached a weight of 150 pounds and a shoulder height of 2.5 feet. They were more heavily built than modern gray wolves (C. lupus) and had smaller brains. Males were apparently larger than females. An analysis of estimated bite force suggests the species took relatively large prey.
Dire wolves are often depicted as pack hunters, as in the accompanying reconstruction by Charles R. Knight.
That’s a matter of conjecture, of course. The sheer numbers found at La Brea—at least 3600 individuals—suggests sociality. The wall of dire wolf skulls in the George C. Page Museum of La Brea Discoveries (www.tarpits.org) is a truly impressive sight. In speculating about how so many got trapped in the tar, you can’t help but wonder about the brain size factor. “Hey, Ralph is stuck in something! Let’s go check it out! Uh-oh…” Or maybe it was just pack solidarity. Years ago I overheard a co-worker telling a trainee: “If all the monkeys jump into the fire, whose fault is it—the first monkey’s or the last monkey’s?”
Whether killed outright or scavenged, the Pleistocene megafauna were no easy pickings. Paleopathologists have found a high frequency of chronic reinjuries in both Canis dirus and Smilodon remains from the tar pits. The wolves were subject to crushed paws and fractures of the skull, limbs, and trunk. In a Science article entitled “Tough Times at La Brea,” UCLA biologists Blaire VanValkenburgh and Fritz Hertel reported a rate of tooth breakage in dire wolves, sabertooths, and the extinct American lion three times higher than in comparable modern large carnivores and concluded that the extinct forms must have utilized carcasses more thoroughly. Unlike those of borophagine dogs and the living spotted hyena, the dire wolf’s teeth were not specially adapted for demolishing bone.
One dire wolf lineage crossed the Isthmus of Panama into South America, becoming specialist predators of vicunas, guanacos, and other llama relatives. But they and their North American relatives had died out by 10,000 years ago. Maybe they had a glorious last stand in Patagonia, like Butch and Sundance. Gray wolves, moving down from the Arctic, co-occurred with dire wolves in southern California by the end of the Pleistocene, so interspecies competition may have played a role in the latter’s extinction. Or the dire wolves may have been unable to switch from the vanishing megafauna to other game. Or human hunters may have wiped out the competition. It’s anyone’s guess.
As with Martin’s literary dire wolves, I was unaware of the existence of a breed of dog called the American Alsatian, the result of breeders’ attempts to recreate the bone and body structure of
Canis dirus using German shepherd, English mastiff, Anatolian shepherd, Great Pyrenees, and Malamute stock. Wikipedia says the American Alsatian “does not possess a strong desire for the physical demands of most working dog endeavors”—a diplomatic way of putting it—and does best as a therapy dog. Mammoth hunting is probably out of the question.