Oxytocin is the hormone that binds. A new study has found that it plays a crucial role in keeping pups and seal mothers physically close after birth.
Dr. Kelly Robinson, a University's Sea Mammal Research Unit (SMRU) research associate, has analyzed the behavior of grey seal communities in the North Rona in North Atlantic Island. She found the oxytocin level of a mothering seal increased when she stayed close to her newborn pups.
The seal research could shed new light about the maternal behavior difference in humans. The findings were published in the PLOS ONE journal.
The hormone oxytocin is associated to the ideal maternal behavior and the strong bond between mother and child. It is present in all mothering mammals, including humans. In a 2011 study, a mice study found that injecting oxytocin can tame even the most irresponsible mice mothers.
Robinson said that when the mother and her pups are separated, it often lead to starvation. Separation is also the top cause of newborn death among the gray seal populations.
In terms of infant survival, mothering seals and her pups must stay together amid a busy breeding community.
"The link between oxytocin and maternal behavior not only has important consequences for pup survival in gray seals, but helps us understand why some individuals, including humans, are better mothers than others," added Dr. Robinson.
The research team documented the mothering seal's behavior towards her newborn in the span of the two-year study, particularly during the rearing period. Blood samples from the mothering seals revealed the levels of oxytocin.
Some mothering seals strayed from their newborn between zero and 30 meters (98 feet). However, the mother seals who stayed the closest to their newborns revealed the highest levels of oxytocin in the blood samples. The level decreased as the distance away from the pups increased.
Robinson explained that some mothering seals were better at taking care of their newborns compared to others. The data is also universal even after considering other factors such as the mother's size and age.
"Oxytocin has been linked to optimal maternal behavior in humans and many captive animal species, but this is the first time such a link has been shown in completely wild animals in their natural habitat," added Robinson.
Photo: Martin Cooper | Flickr