Animal emotion remains a fairly contentious area of scientific research, but there is a growing body of evidence to support the idea that nonhuman animals can have feelings. The scientific community may not be ready to use the “L” word for animals, but we are beginning to understand that they do form relationships that are both more complex and insightful than they initially appeared.
While the birds and the bees don’t pre-order roses online or bust out heart-shaped boxes of chocolate for Valentine’s Day, many animal species—yes, even insects and spiders—exhibit courtship behavior to woo their mates (singing mice, anyone?). On the opposite end of the spectrum, animals can also be sneaky and engage in promiscuous behavior that rivals the latest plotline from your favorite soap opera. The physical, chemical, mental, and emotional drivers behind these behaviors are still under active investigation by the scientific community, and we have a few handy examples published in PLOS ONE.
In “Heaven It’s My Wife! Male Canaries Conceal Extra-Pair Courtships but Increase Aggressions When Their Mate Watches,” male domestic canaries, known to be socially monogamous, altered their courtship behavior toward females depending on the audience. Males were generally more aggressive with females around than with males or no one present. Males also courted other females more if their mates weren’t around, which the authors suggested may imply that there are costs (“divorce”) associated with courting other females while a mate watches. Tsk, tsk.
While canaries may be coy, some of our closest relatives display some of the fiercest aggressive and competitive behavior. In the recently published “Till Death (Or an Intruder) Do Us Part: Intrasexual-Competition in a Monogamous Primate,” owl monkey pairs were broken up by intruding “floater” monkeys, which in some cases, resulted in serious consequences for the ousted monkey: disappearance or death. These breakups also had a negative effect on the reproductive success of both the male and female monkey in the pair. Lasting monogamous owl monkey couples produced 25% more offspring than monkeys with two or more partners.
Are animals always heartbreakers? In what researchers consider an act of monogamy, pair-bonded California mice in this study refrained from scent marking when given the opportunity. This may not seem like a proud display of love and loyalty, but in the animal kingdom, scent marking can be a form of advertising for new females. The researchers also found that virgin male mice still participated in scent-marking behavior, providing further evidence that the other animals’ restraint was related specifically to pair bonding.
Just as we see behavioral differences in the animal kingdom, there’s certainly a lot of variety in human love and relationships. Regardless, we’d like to wish you all a happy Valentine’s Day!
Hanson JL, Hurley LM (2012) Female Presence and Estrous State Influence Mouse Ultrasonic Courtship Vocalizations. PLoS ONE 7(7): e40782. doi:10.1371/journal.pone.0040782
Panksepp J (2011) Cross-Species Affective Neuroscience Decoding of the Primal Affective Experiences of Humans and Related Animals. PLoS ONE 6(9): e21236. doi:10.1371/journal.pone.0021236
Ung D, Amy M, Leboucher G (2011) Heaven It’s My Wife! Male Canaries Conceal Extra-Pair Courtships but Increase Aggressions When Their Mate Watches. PLoS ONE 6(8): e22686. doi:10.1371/journal.pone.0022686
Fernandez-Duque E, Huck M (2013) Till Death (Or an Intruder) Do Us Part: Intrasexual-Competition in a Monogamous Primate. PLoS ONE 8(1): e53724. doi:10.1371/journal.pone.0053724
Monkey image, M. Corley/Owl Monkey Project
Graph, PLOS ONE paper, doi:10.1371/journal.pone.0053724