The biological collections at the Pratt consist of 2,500 regional specimens and objects. A marine life collection represents a baseline study of marine plants and animals (wet-preserved) and drift/beach materials (dry-preserved) of Kachemak Bay. There are thirty mounts of marine and freshwater fish featuring common species of Kachemak Bay. There are over 500 mounts, study skins, skeletons, and nests of birds, representing a wide range of bird and mammal species in Alaska, including a collection of 30 salvaged marine mammals, prepared largely as articulated skeletons. One particularly unusual specimen is the massive rib of an extinct Steller’s Sea Cow from Bering Island.
The Pratt’s Herbarium, housed within Natural History Collections storage, contains a collection of over 1,200 specimens, and represents 347 species of plants from around Kachemak Bay and remote, offshore islands.