Leafcutters at Hacienda Baru National Wildlife Refuge

Leafcutters at Hacienda Baru National Wildlife Refuge
Originally uploaded by MichaelDuquetteFowler

Leaf-cutter ants form the largest and most complex animal societies on Earth.

In a few years, the central mound of their underground nests can grow to more than 98 ft across with smaller, radiating mounds extending out to a radius of 260 ft, taking up 320 to 6,500 sq ft and containing eight million individuals.

This mound was at the Hacienda Baru National Wildlife Refuge near Dominical Costa Rica.