Ants are particularly good animals to mimic, (Yes its an animal , it belongs to Insecta Class, Anthropoda Phylum, Kingdom Animalia) Firstly because they available in large numbers & they are distasteful to many other animals or dangerous to eat. So by looking like an ant, the spider mimic is less likely to be noticed or eaten. Few spiders not only look like ants but smell like them as well. By smelling like the ants, the spider is able to enter the ants nest and steal their young ones. These spiders are such good mimics that they trick not only animals that eat ants but they trick the ants as well.
Recently I had attended a Nature Photography workshop at Bandipur. During my stay we had little time or breaks in between our workshop schedule & I used to wander around JLR campus hoping to photograph birds as I had seen Munias, Sunbirds & also Baya Weaver carrying nesting materials. Once while walking down the path towards outskirts of campus, I noticed red ants climbing a water pipe used for gardening.
On close observing found peculiar behaviour of the ant raising its fore legs for other passing ants.
Ahh !! it was an ant mimic spider !!!
See my earlier post on similar mimicry of Mantis & spider here .