A Podomyrma gratiosa worker forages on a tree trunk. These large ants are almost exclusively arboreal, and their swollen legs contain muscles to help them grip the bark firmly. Naracoorte, South Australia

A large Podomyrma gratiosa tree ant attacks a column of smaller Crematogaster workers that pass too close to her nest. The Crematogaster fight back, and even though the large size and heavy armor of the Podomyrma allow it a one-on-one advantage, the superior numbers of Crematogaster give the smaller ants the edge in this fight. Naracoorte, South Australia