Dogs are a very social bunch. Wild dogs will happily live together as a group throughout their lives.

In India there are millions of stray dog families living on the streets. They are often fed small scraps of bread or biscuits.

When this happens, a mother will usually share these with her pups. But if she successfully scrounges some meat, she often keeps it for herself.

That is the finding of a new study looking into how street dogs in India behaved as they scavenged and begged for food.

"They are scavengers and well adapted to a carb-rich diet, and they use a rule of thumb to maximize their meat intake while scavenging," says senior author Anindita Bhadra of the Indian Institute of Science Education and Research in Kolkata.

We had actually expected the mothers to take the altruistic strategy

These seemingly selfish mothers mothers are using an "evolutionarily stable strategy", she says. That is, they maximise their chances of producing lots of offspring by eating plenty of meat, which will keep them healthy.

They will not let their pups starve, "but show enough care for the pups to survive initially, and then let them fend for themselves," says Badra.

The mothers' "selfish" behaviour came as a surprise to Bhadra's team, as they had expected that richer food resources would make the dogs more cooperative. "We had actually expected the mothers to take the altruistic strategy, as these are social, group living animals," she says.

Dog mothers' occasional bouts of selfishishness may have played a role in the domestication of dogs, Bhadra suggests.

If a pup's mother was refusing to share food, it would have encouraged the pup to seek resources elsewhere.

By aligning itself more closely with humans, the pup might have been rewarded with better food than that provided by its own mother.

This is speculative, but if it is true, we may have selfish dog mothers to thank for our domestic dogs.

The study is published in the journal Royal Society Open Science.