New studies are indicating that dogs well-up with tears when they are reunited with their owners. This reaction is suspected to be stimulated by the hormone associated with social bonding, oxytocin. Study volunteers were more likely to cuddle and attend to dewy-eyed dogs, suggesting that these tears are a means to evoke nurturing behaviour. In the study reported in Current Biology, Takefumi Kikusui of Azabu University in Japan said, “dogs have become a partner of humans, and we can form bonds.”