As for why some mammal dads are more caring than others, the researchers believe that such behavior is likely to evolve when males gain a greater certainty of paternity or when future mating opportunities are scarce.
The researchers suspect that offspring of mammal species where both parents provide care grow up much faster.
"For example," Capellini said, "heavier pups among wolves and dogs are more likely to survive winter than lighter siblings, and the resources provided by the father should allow them to reach a larger size faster."
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Charlotta Kvarnemo, a professor in the Department of Biological and Environmental Sciences at the University of Gothenburg, told Discovery News that the results of the new study "are very important to get a better understanding of why male care has evolved in mammals. Next, to understand why it has evolved so rarely compared to other groups, like fish and birds, we need to look more carefully at the various costs to the male of providing such care."
Robert Elwood, a professor emeritus of biological sciences at Queen's University Belfast, reminds that, for the majority of mammal males, fatherly care is literally not in their DNA.
He explained, "Staying with the female and young might appear to be a poor strategy for a male mammal since he is not normally important to the rearing of young because he cannot provide milk."
How all of this relates to humans, however, is a matter of debate. The researchers did not include humans in the study, but Elwood shared his thoughts about our species.
"Human males in many societies provision the family, but how much involvement in the early rearing of the young is probably highly variable both between and within societies," he said. "It may be less in many traditional societies than in modern western societies."
"However," he added, "the role of the male should not be underestimated as he is likely to increase the growth rate and survival of the offspring, increase the mother's ability to have further children, and may provide important teaching that will enhance the future success of his offspring."