On a sunny August 2nd, 1876, the Union scout, lawman, and gunfighter Wild Bill Hickok was shot dead in a tavern in the town of Deadwood, in the Dakota Territory. He had followed the gold rush to the Black Hills of Dakota, hoping to strike it rich. But he spent most of his time drinking and playing poker in the frontier town’s saloons. On that day, he arrived late to the bar, and the only available seat at the poker table left his back to the door. On another day, he might have left, but this day, he chose to stay. That turned out to be a poor choice.
Hickok was a talented poker player. After a degenerative eye disease robbed him of his marksmanship, he relied on cards to make a living. He brought to the poker table all of the focus and cunning he had previously used as a scout and lawman. He could read people easily, and few men could bluff him for long. But all that attention came with a cost – his focus narrowed on the poker table, on watching the men with him, he failed to notice the door open behind him.
The last words he heard were “Damn you! Take that!”, before a bullet entered the back of his head and exited through his cheek. The buffalo hunter Jack McCall, enraged at being embarrassed by Hickok in a previous poker game, had sneaked up on the distracted Hickok and murdered him. On the floor lay the last hand Hickok was ever dealt: a pair of aces and a pair of eights, all black – since then known as the dead man’s hand.
Animals live in groups for many reasons: to control territory or access to resources, to form alliances and, of course, they live in groups because that makes it easier to find a mate. But living in groups comes with costs – including the possibility that all of those wonderful friends surrounding you are making it more likely that you’re going to be eaten by a predator.
Like humans, animals have a limited capacity for attention. They can only pay attention to so many things at one time – trying to do too many things at once causes everything to suffer. (Study-after-study shows that multi-tasking, the Millenial’s favourite pastime, just results in doing five things poorly). For solitary animals, that means their attention is divided between two things: finding food, and avoiding predators. That’s pretty straightforward.
But social animals have to divide their attention among more activities. They have to find food, look around for predators, look around to see if other individuals have located predators, and also pay attention to their needy friends that require constant attention. Heaven-forbid you’re a mother with babies to take care of too. A study published last week in the journal Ethology experimentally considered the cost of companions.
Jennifer Yee and her colleagues studied the brown anole, a ubiquitous lizard found in the Caribbean. Like all small critters, the brown anole is a favourite meal of just about everything bigger than it – but particularly snakes. Anoles rely on their keen eyesight to avoid becoming a snack – if the bushes rustle in a suspicious way they dart to safety. Yee tested the reaction time of anoles by harassing them with a rubber snake. She moved the snake to within a metre of an anole, and then recorded how much time it took for the anoles to notice. Solitary anoles noticed the snake quickly, and ran away. Good for them.
But, anoles live at a fairly high population density, and are regularly distracted by other anoles. They may just be passing through, or they may be angling to steal your territory, or your mates, or your food. Regardless, they bear close watching. So the anoles all keep a tense eye on one another – the same way Hickok might’ve been keeping a close eye on his fellow poker players. That sort of attention comes at a cost. Yee found that when anoles were distracted by the presence of other individuals, it took them twice as long to notice the presence of a predator – and the predator could be moved closer before the anole found it.
That’s bad news for pre-occupied anoles. It was also bad news for Wild Bill Hickok. Distracted by the other poker players, he didn’t notice Jack McCall arriving at the bar behind him. Next time you’re at the bar, take the seat with your back to the wall.
Yee J, et al. 2013. The Costs of Conspecifics: Are Social Distractions or Environmental Distractions More Salient? Ethology 119: 480-488.
Turner, T. 2001. Wild Bill Hickok: Deadwood City – End of Trail. Universal Publishers.