Everything in Houston, TX, is larger than life, including the bat population. In fact, the state is known for the Waugh Bridge Bat Colony, where over one million Mexican free-tailed bats live year-round. Area residents are used to seeing these animals, but problems arise when colonies roost in homes, attics, chimneys, and walls. This is because bats in Houston damage structures with their droppings and body oils. Worse, their feces spreads histoplasmosis, which can cause severe reactions in humans. Bats' presence is revealed through squeaking and scratching noises at dusk, when they prepare to take flight.