Family care? Healed injuries suggest social behavior in ancestral wolves

September 24, 2020

Wolves today live and hunt in packs, which helps them take down large prey. But when did this group behavior evolve? An international research team has reported specimens of an ancestral wolf, Canis chihliensis, from the Ice Age of north China (~1.3 million years ago), with debilitating injuries to the jaws and leg. The wolf survived these injuries long enough to heal, supporting the likelihood of food-sharing and family care in this early canine.

"Top predators are rare in the fossil record because of their position in the food pyramid. Devastating injuries that are healed are even rarer. Fossils preserving grotesque injuries from the distant past have long fascinated paleontologists, and they tell stories rarely told," noted Dr. Xiaoming Wang, curator of vertebrate paleontology at the Natural History Museum of Los Angeles County, who co-led the study.

Dr. Haowen Tong, professor at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences in Beijing, led the excavations that discovered the fossils in the Nihewan Basin, a well-known Ice Age site in northern China.

Based on its skeleton, C. chihliensis was a large canine with strongly built jaws and teeth specialized for eating meat and cracking bone. Injuries in the skeleton provide additional evidence for how the animal used to move and behave. The study represents the first known record of dental infection in C. chihliensis, likely incurred while crushing bone to reach the marrow inside, which modern wolves do when hunting prey larger than themselves.

One C. chihliensis also badly fractured its shin (tibia), splintering it into three parts. The injury must have incapacitated the wolf, an active predator that hunted by chasing prey--yet it survived, as evidenced by healing of the bone. Survival suggests that, while recovering, it procured food in some way other than by hunting--likely with the support of a pack.

To help interpret the injuries, the study also examined specimens of another extinct large canine: the dire wolf, Canis dirus, which has abundant fossils at the world-famous Rancho La Brea asphalt seeps in Los Angeles, California. The dire wolf was geologically younger than C. chihliensis, having lived at Rancho La Brea approximately 55,000 to 11,000 years ago. Despite the age difference, the dire wolf--which previous studies had established to have been a pursuit predator of large prey, with a social structure likely similar to grey wolves today--sustained injuries to the teeth, jaws, and legs similar to C. chihliensis.

"It is incredible to see these dental infections and fractured tibia from this early Chinese wolf--and find similar injuries in our dire wolves at Rancho La Brea," said Dr. Mairin Balisi, National Science Foundation postdoctoral research fellow at the La Brea Tar Pits and Museum, and co-author of the study. "Museum collections are valuable for many reasons. In this case, they've enabled us to observe shared behavior across species, across continents, across time."
-end-


PeerJ

Related Ice Age Articles from Brightsurf:

Ice discharge in the North Pacific set off series of climate events during last ice age
Repeated catastrophic ice discharges from western North America into the North Pacific contributed to, and perhaps triggered, hemispheric-scale changes in the Earth's climate during the last ice age.

Ice Age manatees may have called Texas home
Manatees don't live year-round in Texas, but these gentle sea cows are known to occasionally visit, swimming in for a 'summer vacation' and returning to warmer waters for the winter.

Sea ice triggered the Little Ice Age, finds a new study
A new study finds a trigger for the Little Ice Age that cooled Europe from the 1300s through mid-1800s, and supports surprising model results suggesting that under the right conditions sudden climate changes can occur spontaneously, without external forcing.

How cold was the ice age? Researchers now know
A University of Arizona-led team has nailed down the temperature of the last ice age -- the Last Glacial Maximum of 20,000 years ago - to about 46 degrees Fahrenheit.

What causes an ice age to end?
Research by an international team helps to resolve some of the mystery of why ice ages end by establishing when they end.

New study results consistent with dog domestication during ice age
Analysis of Paleolithic-era teeth from a 28,500-year-old fossil site in the Czech Republic provides supporting evidence for two groups of canids -- one dog-like and the other wolf-like - with differing diets, which is consistent with the early domestication of dogs.

Did an extraterrestrial impact trigger the extinction of ice-age animals?
Based on research at White Pond near Elgin, South Carolina, University of South Carolina archaeologist Christopher Moore and 16 colleagues present new evidence of a controversial theory that suggests an extraterrestrial body crashing to Earth almost 13,000 years ago caused the extinction of many large animals and a probable population decline in early humans.

Dust in ice cores leads to new knowledge on the advancement of the ice before the ice age
Working with the ice core ReCap, drilled close to the coast in East Greenland, postdoc Marius Simonsen wondered why the dust particles from the interglacial period -- the warmer period of time between the ice ages -- were several times bigger than the dust particles from the ice age.

Ice-sheet variability during the last ice age from the perspective of marine sediment
By using marine sediment cores from Northwestern Australia, a Japanese team led by National Institute of Polar Research (NIPR) and the University of Tokyo revealed that the global ice sheet during the last ice age had changed in shorter time scale than previously thought.

What triggered the 100,000-year Ice Age cycle?
A slowing of ocean circulation in the waters surrounding Antarctica drastically altered the strength and more than doubled the length of global ice ages following the mid-Pleistocene transition, a new study finds.

Read More: Ice Age News and Ice Age Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.