A new analysis out of Penn State University has dug up hints that dogs -- some of the earliest domesticated canines -- helped with early mammoth hunts.

Archeological sites in Europe that contained the remains of many mammoths and dwellings built with mammoth bones led Pat Shipman, a Penn State professor, to suspect such sites -- which appeared rather abruptly in the prehistoric time line -- resulted when early humans cooperated with the earliest domestic dogs to hunt the now-extinct mammoth.

Published online in the journal Quaternary International, the new study explains grand prehistoric enclaves containing stone tools and extraordinary numbers of dead mammoths -- with some locations holding the remains of hundreds of individual beasts -- suddenly became common in central and eastern Eurasia about 45,000 to 15,000 years ago.

Though mammoths had been hunted by humans and their ancestors for a million years or so prior, the shear volume of dead mammoths at the sites was astounding, said Shipman. Of equal note, some of the locations had huts built of mammoth bones in complex, geometric patterns, along with notable piles hacked mammoth bones.

"One of the greatest puzzles about these sites is how such large numbers of mammoths could have been killed with the weapons available during that time," said Shipman, who asserted earlier studies lacked the statistical evaluations necessary for determining with any certainty how these animals were killed.

Shipman explained in the study that she found "few of the mortality patterns from these mammoth deaths matched either those from natural deaths among modern elephants killed by droughts, or by culling operations with modern weapons that kill entire family herds of modern elephants at once."

Her realization about how the ancient animals met their demise suggested a successful new technique for killing such large animals had come on scene and was subsequently be used over and over, which explained the successful killing of so many mammoths.

The pieces to Shipman's new hypothesis fell into line with recent work by a research team from the Royal Belgian Institute of Natural Sciences, which uncovered evidence some of the large carnivores at the sites in question weren't wolves, as some had assumed before, but early domesticated dogs.

Shipman then formulated a series of testable predictions about the mammoth sites, based on how humans and dogs hunt together

"Dogs help hunters find prey faster and more often, and dogs also can surround a large animal and hold it in place by growling and charging while hunters move in. Both of these effects would increase hunting success," Shipman said. "Furthermore, large dogs like those identified by [the Royal Belgian Institute study] either can help carry the prey home or, by guarding the carcass from other carnivores, can make it possible for the hunters to camp at the kill sites."

Additionally, she said, "if hunters working with dogs catch more prey, have a higher intake of protein and fat, and have a lower expenditure of energy, their reproductive rate is likely to rise."

Another significant feature at the mammoth kill sites was the large numbers of other predators, in particular wolves and foxes.

"Both dogs and wolves are very alert to the presence of other related carnivores -- the canids -- and they defend their territories and food fiercely," Shipman said. "If humans were working and living with domesticated dogs or even semi-domesticated wolves at these archaeological sites, we would expect to find the new focus on killing the wild wolves that we see there."

Another site study from the University of Tubingen in Germany examined the bones of wolves and another species believed to be dogs from the Czech site of Predmostí -- and found that the individuals identified as dogs had different diets from those identified as wolves, possibly indicating feeding by humans.

As well, DNA analyses from a number of other research groups, including one from the University of Turku in Finland, showed the animals at the kill sites identified as dogs had a distinctive genetic signature not known from any other canid, perhaps demonstrating "these odd canids did not give rise to modern domesticated dogs and were simply a peculiar, extinct group of wolves," Shipman said.

"Alternatively, it may indicate that early humans did domesticate wolves into dogs or a dog-like group," though that lineage was lost through time.

Bottom line, said Shipman, her new study underscores the long-held belief that "dogs may indeed be man's best friend."