Happy, Sane Males Have Better Love Lives

It turns out that happy, sane males have better love lives--or at least, mink do. Scientists have discovered that mink raised in enriched environments are much more successful during the mating season than those that happen to be stressed and upset. The findings may help improve mating among captive animals, especially among endangered species such as giant pandas and Canada's rare black-footed ferrets.

"With many captive carnivores, it can be hard to get males to mate: some are too aggressive, while others just seem not that interested," said Georgia Mason, one of the researchers, in a news release. "Our findings suggest that improving their welfare via better housing could help make the difference. We also hope our results will encourage more use of enrichments on mink farms."

In this study, the researchers used 32 male and 32 female American mink. Half of the male mink were raised in enriched cages, which included pools, toys and swings. Over two years, the same males were offered as mates to two different sets of female mink, which were free to wander and choose between enriched or non-enriched males. In addition, males were placed in the same exact cages during mating time.

So what did they find? It turned out that males raised in better conditions mated nearly twice as often as other males. In addition, males from enriched houses usually were physically bigger and heavier, with bigger spleens which indicated better immune systems. They also had higher testosterone levels, which suggested greater libidos, and even had better developed penis bones.

"We can't tell if the enriched males are more attractive, keener on mating or both," said Mason in a news release. "But the secret to their success is their calmer, more normal behavior."

The enriched males actually avoided the repetitive pacing and head-twirling that's common among mink raised in non-stimulating environments. This calmer behavior seemed to make them more attractive to females.

"Our results confirm what has long been suspected: that males raised in barren environments are at risk of developing into physically and psychologically unattractive adults, which affects breeding in captivity," said Maria Diez-Leon, one of the researchers, in a news release. "Enriched housing conditions could provide a solution, with the added benefit of enhancing animals' welfare."

The findings are published in the journal PLOS One.