Their aggressive behaviour was captured by Paul Quagliana, 43, a wildlife photographer, who found a colony of the ants on a log in Wareham Forest, Dorset. In order to trigger the insect’s reaction, he gave their nest a tap, which prompted the ants to squirt acid in the air from their tiny abdomens. ‘There are many different species of woodland ants in Britain and these are called Formica rufa,’ said Mr Quagliana, who lives in Gillingham, Dorset. ‘As a defence mechanism they squirt formic acid which smells a bit like salt and vinegar crisps or fish and chips,’ he explained.From the Mail Online, via The Soul is Bone.
Addendum: Video here, narrated by David Attenborough.