A new study claims that it is the mother's scent that draws baby mice in for initial suckling.
Researchers at the Scripps Research Institute found that baby mice begin to suckle their mother's milk after learning her unique combination of odors.
The baby is first exposed to the odors from the mother's amniotic fluid.
The researchers were surprised to find that it is not a pheromone that draws the babies near.
"Surprisingly, unlike the rabbit, we found no evidence of a classic pheromone in the mice," said study author Lisa Stowers, according to Science Codex.
"Instead, we found that the pup 'learns' the individual scent blend of the mom. Every mom is likely to have a different signature odor."
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Suckling is necessary for the survival of mammals.
Newborns that fail to begin to feed from the mother often die of dehydration early in life.
Until now, it has been a mystery to researchers how the process began.
"We set out to find a pheromone trigger, but were excited to find this alternative mechanism," said Stowers, reported Science Daily.
"Compared to a pheromonal system, this mechanism would have been easier for animals to evolve."
The study was published in Current Biology.