Ant-mimicking spiders (Araneae: Salticide) are fascinating creatures that have evolved modified morphology and behaviours to resemble those of ants (Hymenoptera: Formicidae). Ant-mimicking spiders are cosmopolitan but currently, there are no records of such spiders in fossilised resin, nor any records of extant ant- mimicking spiders in Colombia, S.A. The present study describes Myrmarachne colombiana sp. n. (Araneae: Salticidae) as the first species of ant-mimicking spider in fossilised resin (copal) from Colombia, discusses possible ages of copal inclusions around the world, and examines various scenarios showing why spiders have become ant mimics.