Healthy Mum With Lots of Help Raise Kids That 'Thrive': Researchers

"Using 14 years of data from the long-term study of wolves in Yellowstone National Park, we examined a number of key traits that allow wolves to overcome environmental stress," said Dan MacNulty, assistant professor in USU's Quinney College of Natural Resources.

"We discovered mother wolves' body weight and pack size play a crucial role in enabling pups to survive and thrive from birth to young adulthood," he stated.

MacNulty conducted the study with Dan Stahler and Doug Smith of the National Park Service's Yellowstone Wolf Project, as well as Robert Wayne and Bridgett vonHoldt of the University of California, Los Angeles.

Environmental conditions that impact wolf reproduction, the researchers said, include disease prevalence, especially deadly canine distemper - caused by a contagious virus to which pups are especially vulnerable; resource availability and population density. In addition to body weight and pack size, the researchers examined effects of maternal age, colour (gray or black coat) and wolf population size on reproductive success.

"Each of these factors affects reproduction but, overwhelmingly, female body weight and pack size are the main drivers of litter size and pup survival. Bigger females produce bigger litters; bigger packs are better equipped to hunt and defend pups and resources from competitors," said Stahler, the study's lead author.

Social carnivores, wolves live in territorial, kin-structured packs. Female wolves depend on other adults in the pack to help them provide food for their pups and defend the youngsters from predators; mainly, competing packs of wolves.

"Motherhood is a challenge for any species. But the evolution of cooperation in wolf societies is a notable benefit to mother wolves," Stahler stated.

As wolf management in the United States moves from recovery to a new era of conservation, the researchers believe knowledge of reproduction will help managers maintain wolf populations.

If pack sizes are small, female wolves are underweight or disease outbreaks occur, MacNulty said, managers could reduce harvest to ensure sufficient numbers of breeding pairs.

On the other hand, if pack sizes are relatively large, female wolves are at healthy weights and acute diseases are absent, managers can have confidence that current harvest levels are appropriate.

The researchers published their findings in the online edition of the Journal of Animal Ecology.

Source-ANI