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鈥�CATAGLYPHIS is only an ant, but truly what an ant,鈥� writes R眉diger Wehner in the prologue to Desert Navigator. A chapter into his new book, I also came under the spell of this long-legged 鈥�racehorse of the insect world鈥� and the staggering navigational skills that emerge from the 500,000 neurons in its brain, which weighs less than a tenth of a milligram.

As a young biologist, Wehner fell for them when he visited a Tunisian salt pan and saw one pick up a dead insect and sprint 100 metres across the featureless desert to its inconspicuous nest hole. How did the ant know where to go? Fifty years later, thanks to Wehner, now director emeritus of the Institute of Zoology at the University of Zurich, Switzerland, and the researchers he inspired, we have many of the answers, laid out in this grand book.

As Wehner realised early on, Cataglyphis is a 鈥渕odel organism鈥� for studying animal navigation. The ants run about on flat, open surfaces, so it is easy to track them and explore their talents. The secrets revealed in five decades of research are extraordinary.

One of the first surprises is that these ants can do what human navigators call 鈥渄ead reckoning鈥�: keeping a continuous tally of both direction and distance covered so that they can always compute the direction of home.

As their compass, the ants use the polarisation pattern of the sky, as well as Earth鈥檚 magnetic field and the desert wind. Gauging distance is done with a 鈥減edometer鈥� 鈥� the ant counts its steps 鈥� and by sensing the 鈥渙ptic flow鈥�, or relative motion, of the ground beneath it as it runs.

If the desert contains landmarks, such as rocks, the ants are superb at using them for navigation too. When an ant leaves the nest, Wehner describes how it faces back towards the entrance and pauses to take 鈥渟napshots鈥� of its surroundings. Later, it compares those snapshots with the current view to spot the way home.

Wehner explains many more fascinating ant skills before he moves on to his pioneering studies on the harder question of how the ant integrates all that information with its memory to decide where to go. This is the frontier where field studies meet computational modelling, robotics and neuroscience.

鈥淭hese insects do what we call dead reckoning, tallying direction and distance so they always know the way home鈥�

So far, research seems to settle one long-running debate: the ants don鈥檛 form a mental 鈥渕ap鈥� of their surroundings as many researchers have argued. Although they are superb navigators, they keep things simple. They never actually know where they are but only where to go. If that sounds confusing, it is a little like what you might do on a stroll from a hotel in an unfamiliar city. You may not know where you are, but you can find your way home by remembering things like: 鈥淚 turned left at a big supermarket.鈥�

Desert Navigator is written in a concise and serious style. You will need to give time to its many explanatory diagrams, but the rewards are insights into 鈥渢he process of thought that leads to the solution鈥�, and the ingenuity of the experiments that Wehner and others have devised to work out how the ants do their thing.

For example, to show that the insects were counting steps to estimate distance, tiny stilts were glued to their legs to lengthen their stride. Sure enough, they changed their distance estimates. And to show that the ants really sense optic flow, a runway was built in the desert with a moving pattern of stripes beneath it. That, too, altered their perception of how far they had run.

You will end the book as a fan of Cataglyphis, for the creature is more than just a navigator. Early in life, the ants nurse the brood, then become 鈥渆xcavators鈥�, and finally, after initial timid trips, they sprint off from the cool of the nest into the ferocious desert heat to forage.

Outside, their achievements are amazing. They can move fast, covering up to 110 body lengths a second; in human terms, about 600 kilometres per hour. They must dodge danger everywhere. Robber flies attack from the air, jumping spiders from the surface and tiger beetles from below ground. A forager is usually dead within five to seven days, even though the ants live for months in a lab. But food must be found. What a life and, yes, what an ant.