Coptotermes gestroi and Heterotermes tenuis (Isoptera: Rhinotermitidae) are important pests in southeastern Brazil causing serious economic damage. In this study we determined the demographic patterns and foraging activity of these species using mark-release-recapture and the consumption of wooden stakes. Using both the weighted mean and Lincoln index methods, population estimates ranged from ≈ 0.57 to 1.99 million individuals for C. gestroi and from ≈ 0.20 to 1.37 million for H. tenuis. Territory size of the colonies ranged from 172.5 to 5235 m2 for C. gestroi and from 16 to 40 m2 for H. tenuis. Our results also indicate that foraging activity was dependent on the minimum temperature; however, the existence of a compensation strategy in the foraging activities may permit foragers to exploit food sources under different environmental conditions.