Love that dog – the oxytocin way!

Here is a short article about some interesting research, concerning the “oxytocin theory” of dogs and social bonding. Oxytocin is a hormone found in mammals, including humans. It has various functions. It produces the let down reflex when mothers are breast feeding, it stimulates the onset of labour and it is released when women experience orgasm. It is also thought to be produced in other situations where close contact and bonding occurs, possibly when people pat their dogs. It may be that our human ancestors breast fed puppies or cubs, who were the ancestors of domestic dogs. This bonding process may have been part of the process of domestication of dogs.

Oxytocin promotes social bonding in dogs

Article by Teresa Romero, Miho Nagasawa, Kazutaka Mogi, Toshikazu Hasegawa and Takefumi Kikusui.

Significance

Although the positive impact of social bonds on individual’s fitness has recently been demonstrated, the mechanisms underlying the motivation to form long-term associations remain largely unknown. Current evidence shows that oxytocin modulates social behavior but evidence of its effects in bond maintenance remains scant, especially in nonreproductive contexts. We provide evidence that in the domestic dog oxytocin enhances social motivation to approach and affiliate with conspecifics and human partners, which constitutes the basis for the formation of any stable social bond. Furthermore, endogenous oxytocin levels increased after dogs engaged in affiliation with their dog partners, indicating a stimulation of the oxytocin system during social interactions. Our findings highlight the important role that oxytocin has in the expression of sociality in mammals.

Abstract

Recent evidence suggests that enduring social bonds have fitness benefits. However, very little is known about the neural circuitry and neurochemistry underlying the formation and maintenance of stable social bonds outside reproductive contexts. Oxytocin (OT), a neuropeptide synthetized by the hypothalamus in mammals, regulates many complex forms of social behavior and cognition in both human and nonhuman animals. Animal research, however, has concentrated on monogamous mammals, and it remains unknown whether OT also modulates social bonds in nonreproductive contexts. In this study we provide behavioral evidence that exogenous OT promotes positive social behaviors in the domestic dog toward not only conspecifics but also human partners. Specifically, when sprayed with OT, dogs showed higher social orientation and affiliation toward their owners and higher affiliation and approach behaviors toward dog partners than when sprayed with placebo. Additionally, the exchange of socio-positive behaviors with dog partners triggered the release of endogenous OT, highlighting the involvement of OT in the development of social relationships in the domestic dog. These data provide new insight into the mechanisms that facilitate the maintenance of close social bonds beyond immediate reproductive interest or genetic ties and complement a growing body of evidence that identifies OT as one of the neurochemical foundations of sociality in mammalian species.

Footnotes

• ¹To whom correspondence may be addressed. E-mail: tromero@darwin.c.u-tokyo.ac.jp or nagasawa@carazabu.com.

• Author contributions: T.R., M.N., K.M., T.H., and T.K. designed research; T.R., M.N., and K.M. performed research; T.R. and M.N. analyzed data; and T.R. wrote the paper.

Another article

A potent new spray promotes friendship between animals even, in some cases, if they come from different species, according to a new study.

The spray’s active ingredient is oxytocin, which is a naturally occurring hormone released by the pituitary gland. When formulated into a spray, it becomes a veritable Love Potion Number 9, with more emphasis — at least in this case — on friendly rather than romantic interactions.

The study, published in the latest issue of the Proceedings of the National Academy of Sciences, looked at how the spray affects dogs, but it holds tremendous promise for human usage too. It might even help to reform curmudgeonly cats.

“Studies in humans have already shown that oxytocin affects our tendency to affiliate or cooperate with other people,” co-author Miho Nagasawa of the University of Tokyo’s Department of Cognitive and Behavioral Sciences told Discovery News.

“As far as we know, there are no studies on cats, but we believe that oxytocin is a hormonal mechanism that facilitates the maintenance of close social bonds not only in dogs or cats, but also in any mammal species since the oxytocin system is very ancient and has similar functions in a wide number of taxa,” Nagasawa added.

Lead author Teresa Romero, Nagasawa and their colleagues studied how 16 adult dogs of different breeds behaved both with and without being sprayed by the oxytocin formulation. All of the dogs are pets that live with their owners.

Dogs Remember Our BO When We’re Away

The scientists recorded any instance of bonding behavior that the dogs showed with other familiar dogs as well as with their owners. The behaviors included sniffing, licking, gentle touching with the nose or paw, playing and resting in contact with the other’s body. The researchers also measured how much attention the dogs paid to their owners or to their canine pals.

“We found that after receiving the oxytocin spray, dogs displayed more affiliative behaviors and paid more attention to their owners than during the controls,” Romero told Discovery News.

As for how the spray works, the researchers said it significantly changed the dogs’ heart rate variability and stimulated secretion of oxytocin. These indicate that the spray “can penetrate into the brain and stimulate the oxytocin system in the central nervous system,” Nagasawa said.