MEET THE ANIMAL ARCHITECTS

WE THINK WE'RE PRETTY CLEVER BY BUILDING THE GHERKIN AND THE SHARD, BUT THESE ENTERPRISING ANIMALS CAN CREATE SOME SMART STRUCTURES OF THEIR OWN... SOME OF WHICH EVEN HAVE BUILT-IN AIR CONDITIONING

- BEN HOARE

LIVING BRIDGES

Army ants in huge raiding columns will deploy their own bodies to form living bridges so fellow workers can cross gaps quickly. A bridge consists of up to 50 ants and a colony may have 40 or 50 bridges in use at any time. Myrmecologists (people who study ants) at the New Jersey Institute of Technology's Swarm Lab have worked out a simple rule governing this behaviour. Ants only stay in a bridge if they feel sufficient numbers of other ants scurrying over their backs. To justify investing that much labour, the shortcut has to be popular. If fewer ants cross, forming a bridge isn't worth the effort - it's better for the colony if these ants go around the obstacle the long way.

IT'S A WRAP

In 2010, countless trees were left shrouded in swathes of silk in Pakistan following monsoon rains. It's thought that the flood waters forced millions of spiders to take refuge in the trees, where they spun these veil-like webs. Though the identity of the spiders in this image is not known, some species will congregate in composite webs, often resembling huge hammocks or sheets. Spiders live alone as a rule, but some - most of which are small and occur in the tropics - exhibit varying degrees of social behaviour. Communal webs enable them to catch much bigger prey and share the energy-sapping tasks of spinning the webs and maintaining their structure. Occasionally, enormous megawebs appear, covering several hundred square metres in silk, perhaps because a superabundance of prey caused an explosion in the local spider population.

WHEELS OF FORTUNE