They showed experimentally that pigeons can find solutions, close to optimal, to simple cases of a famous mathematical curiosity: the Travelling Salesman Problem.

Now, in a paper posted online in July, Klein and his advisers at the University of Washington, Anna Karlin and Shayan Oveis Gharan, have finally achieved a goal computer scientists have pursued for nearly half a century: a better way to find approximate solutions to the traveling salesperson problem.