Meet the old wolves, same as the new wolves

From Austin, Texas, at a meeting of the Society of Vertebrate Paleontology

An analysis of fossils from southern California’s La Brea tar pits hints that the dire wolf, a species that died out at the end of the last ice age, had a social structure similar to that of its modern-day relatives.

Dire wolves are the most common predators entombed at La Brea (SN: 1/24/04, p. 56). Adults were only slightly larger than today’s gray wolves but had larger, broader heads and stronger teeth, which the creatures presumably used to crush bones (SN: 7/27/02, p. 51).

Sherri Gust, a paleontologist at Cogstone Resource Management in Santa Ana, Calif., analyzed the pelvic bones of almost 400 dire wolves excavated at La Brea. The degree and number of fusions in those bones, as well as their size, enabled her to estimate the age of each individual.

Of the fossils Gust analyzed, about 6 percent represented wolf cubs between 6 months and 1 year of age, and about 25 percent represented wolves that were nearly full grown. The largest category, young adults, comprised almost 39 percent of the individuals. Middle-aged wolves accounted for about 24 percent of the fossils, with the remaining 7 percent representing old members of the pack.

The prevalence of young adults in the sample, closely followed by adolescents and middle-aged individuals, suggests that they were the dominant members of the pack. That’s the pattern seen in wolf packs today, says Gust. The absence of pups younger than 6 months of age hints that dire wolves, like their modern kin, kept the youngsters sequestered in dens and fed them by regurgitation.