Puppies that are fussed over by attentive mothers are handicapped in later life, a study has found.
Scientists used a challenging training course undergone by guide dogs as a measure of the puppies’ future ability to cope in the real world.
Those that had doting, over-protective mothers were less likely to complete the guide dog tests successfully.
Emily Bray, from the University of Pennsylvania, said: “It’s remarkable. These puppies were with their mom for only five weeks and it’s having an effect on their success two years later. It seems that puppies need to learn how to deal with small challenges at this early age and if they don’t, it hurts them later.”
The researchers studied 23 mothers and their 98 puppies at a breeding centre run by The Seeing Eye, a US guide dog school, in New Jersey. “We wanted to know if we could differentiate the moms based on how they interacted with their puppies,” Dr Bray said. “We documented things like her nursing position, how much time she spent looking away from the puppies and how much time she spent in close proximity to her puppies or licking and grooming them.”
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Some mothers turned out to be more attentive than others. Tests showed the more vigilant mothers had higher stress levels, which spiked when their puppies were temporarily removed. Two years later the researchers found puppies raised by highly attentive and stressed mothers had less chance of graduating from The Seeing Eye’s training programme to become guide dogs.
In particular, dogs whose mothers tended to nurse lying down instead of sitting or standing up were less likely to succeed.
Robert Seyfarth, another member of the Pennsylvania team, said: “If a mother is lying on her stomach, the puppies basically have free access to milk but if the mother is standing up then the puppies have to work to get it.
“A hypothesis might be that you have to provide your offspring with minor obstacles that they can overcome for them to succeed later in life because, as we know, life as an adult involves obstacles.”