“Hunting for food, ants roam haphazardly. But when they find it, they use celestial cues, perhaps from the sun, to head back to their nests more or less in a straight line – rather than retracing the tortuous journeys they’d made on their outbound searches.
So how does an ant know when to stop running?
It must not be based on seeing the nest entrance, because a returning ant rarely runs straight down into its hole. Instead, when they think they’re in the right area, they stop running, make a U-turn, and pace back and forth until they find it.”
Scientists showed that they ‘count’ their steps by giving some ants stilts and amputating the last segment off the legs of other ants (ants’ legs can’t feel anything because they have to walk across boiling sand). The ants with stilts overshot their nest by 50% and the ants with stumps only got halfway home.
“Interestingly, the ants quickly adjusted to their new leg lengths. The next day the modified ants were allowed to engage in normal foraging, and they returned to the nest as well as the unmodified ants.”
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