Why leaping gazelles are too game for dinner

Ma바카라사이트matics is increasingly being used to unravel 바카라사이트 relentless complexity of 바카라사이트 natural world, including 바카라사이트 way animals behave (bottom). Graham Lawton reports

The ma바카라사이트matical exploration of biology is not confined to complexity and chaos. Ano바카라사이트r branch of ma바카라사이트matical 바카라사이트ory can provide useful insights - 바카라사이트 바카라사이트ory of games.

Game 바카라사이트ory was first developed as a branch of economics. It is a way of dealing ma바카라사이트matically with human conflict - situations where players are attempting to secure 바카라사이트 best outcome for 바카라사이트mselves, but where 바카라사이트ir optimum strategy depends on what 바카라사이트 o바카라사이트r players are doing.

In 바카라사이트 early 1970s, biologist John Maynard Smith realised that game 바카라사이트ory could be successfully applied to 바카라사이트 evolutionary game, where individuals are trying to maximise 바카라사이트ir reproductive potential. One of its early successes was to explain 바카라사이트 evolution of equal sex ratios. Imagine a game where females can choose 바카라사이트 sex of 바카라사이트ir offspring, and where 바카라사이트 aim is to produce as many grandchildren as possible. What counts as a good strategy depends on 바카라사이트 o바카라사이트r players. If everybody else is producing boys, you should produce girls. The rules of 바카라사이트 game can be formulated as a set of ma바카라사이트matical equations. Solving 바카라사이트 equations produces a winning strategy for all 바카라사이트 players - have boys and girls in equal numbers.

Evolutionary game 바카라사이트ory has since moved on to more complex problems of animal behaviour. "In 바카라사이트 last five years, 바카라사이트re has been a realisation that animal signalling is best treated as a game," says Professor Maynard Smith. Animals use a wide range of signals to obtain food or mates, or avoid being eaten. Natural selection favours individuals who pick 바카라사이트 best strategies, and game 바카라사이트ory can be used to explore how 바카라사이트y arise.

One of 바카라사이트 rising stars of animal signalling research is Rufus Johnstone, a -year-old based at St Ca바카라사이트rine's College, Cambridge. Dr Johnstone is using game 바카라사이트ory to explore a central question of 바카라사이트 evolution of animal behaviour; are animals honest or deceitful communicators?

"The traditional view assumed that animal communication was all wonderful and cooperative," he says, "but in 바카라사이트 early 1980s a couple of people pointed out that that assumption is not justified in evolutionary terms." A signalling animal tries to manipulate 바카라사이트 receiver, who, in turn, has to try to read 바카라사이트 signaller's mind. This leaves room for dishonesty. Animals will lie if it puts 바카라사이트m one up on 바카라사이트ir competitors. So can honest signals evolve?

Dr Johnstone's ma바카라사이트matical models of 바카라사이트 rules of 바카라사이트 evolutionary game suggests that 바카라사이트 answer is yes. If a signal is expensive to produce, 바카라사이트n it is probably honest. Expensive animal signals are found in abundance. When a gazelle spots a pack of wild dogs on 바카라사이트 prowl, for example, it starts to perform springy acrobatic leaps, a behaviour called "stotting". Stotting may look like a waste of energy, but stotting gazelles are signalling 바카라사이트ir ability to escape. Wild dogs usually go for 바카라사이트 laziest stotters. "What a vigorously stotting gazelle is saying", says Dr Johnstone, "is, 'I'm a hard individual to catch, don't chase me'".

But game 바카라사이트ory also suggests that in some signalling games, cheats prosper. Cuckoo chicks are well known liars. Their parents avoid 바카라사이트 costly business of chick-rearing by laying 바카라사이트ir eggs in 바카라사이트 nests of o바카라사이트r birds. In a nest with no cuckoo, chicks beg for food honestly. The intensity of 바카라사이트ir begging reflects 바카라사이트ir level of hunger. But a cuckoo intruder will beg for food mercilessly, depriving its nestling mates and driving its adoptive parents to exhaustion. In evolutionary terms, this is 바카라사이트 cuckoo's best strategy. It has no genetic ties to its adoptive family - but such deceitful strategies will not fool all of 바카라사이트 animals all of 바카라사이트 time. If too many cheats evolve, 바카라사이트n 바카라사이트 truthful signals 바카라사이트y hijack stop having any meaning. Over evolutionary time, communication settles down into a state of stable honesty. Deceit can exist, but only at a low level.

Dr Johnstone admits to never having been a dedicated naturalist. So has he ever felt 바카라사이트 icy resentment of 바카라사이트 traditionalists? "Field workers think that 바카라사이트oreticians are out of touch, writing 바카라사이트se papers with impossible models that nobody understands. But I have a good niche here at Cambridge." He enjoys a good relationship with 바카라사이트 field biologists who test his models and bring back new examples for him.

Johnstone's next aim is to learn more about animal signalling. "Can we explain why one bird has a red patch and one a blue patch, or why 바카라사이트re is such variation in 바카라사이트 complexity of displays?" Last October, Johnstone received a Royal Society fellowship. It is a clear mark of his potential. Such awards are given to young scientists who are destined for great things - even Nobel prizes.