Pond bats are one of the largest bats in Estonia. Their back can be anything from ash-grey to chestnut-brown, but also blackish-brown and completely black. Their stomachs are usually greyish-white. They live in sparse small woods and areas that alternate with trees and clearings. They feed on smaller lakes, ponds, and slow-flowing rivers. They eat mosquitoes, midges, and other smaller insects, which they catch while flying near the water surface, rarely flying higher. Their flight style is powerful, but their moves are slow and smooth. They do not make sudden turns. They can fly all night long, taking only short breaks. During daytime, they hide under roofs, in wall cracks, and in tree hollows. At the end of May, the females come together and form farrowing colonies, which may contain dozens to a hundred bats. During that time, male bats live alone or in smaller groups, but not with the female animals. The farrowing colonies often inhabit the cocklofts of churches. Under protection (protection category II). More than 65 species of mammals have been registered in Estonia, 14 of which are bats or Chiroptera. There are about 500,000 bats in Estonia. In Tallinn, their most important feeding places are Kadriorg Park, Pirita River Valley, Raku lakes, the area surrounding Ülemiste Lake, Astangu, and Rocca al Mare.