A Convenient Scent

Life can be tough for males of many species as they indulge in intense competition for food and females. The answer to some is to pretend to be what they’re not. Then they may achieve by stealth and deceit what they may fail to attain by direct action.

Male cuttlefish, for example, can switch to female coloring to get close to a female that they’ve set their sights on without being challenged by other males. Then at the last minute, they can show their true colors and steal a march on their competitors. Similar to an old trick common to buccaneers on the Spanish Main.

But switching colors is not a choice open to all. Insects, for example, can play games with their pheromones to gain food or sex advantage. Vertebrates find this mimicry business a little more demanding, but not impossible.

Red-sided garter snakes in Manitoba have some problems early on the year when they emerge from their hibernation. This has been extensively studied by Shine et al (1). They wake up and start to move around, cold and still half asleep. At this point they are easy prey for crows who love a nice breakfast of garter snake.

The early risers who have dodged the crows are nicely warmed up and the males are trying to work their magic on the females in their large communal courtship arena. Cold and sleepy makes competing difficult so what’s a poor male garter snake to do?

They pretend to be females. Amorous males get up close and personal and warm them up as well as protecting them. How does a red-sided garter snake become a temporary transvestite? They secrete lipids in their skin, which smell like female to any red-blooded red-sided male garter snake.

 At the low temperatures, the more male like components that aren’t as volatile don’t ring alarm bells. By the time their suitors have warmed them up, they can drop the disguise and get down to the serious business of looking for females.

  1. R. Shine, T. Langkilde & R.T. Mason, J Behav. Ecol. Sociobiol., (2012). Doi: 10.1007/s00265-012-1317-4

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