Barro Colorado Island (BCI) is located in the man-made Gatun Lake in the middle of the Panama Canal. The island was formed when the waters of the Chagres River were dammed to form Gatun Lake. When the waters rose, they covered a significant part of the existing rainforest, and the hilltops remained as islands in the middle of the lake. It has an area of 15 square kilometres.
The island was set aside on April 17, 1923 as a nature reserve by the U.S. Government. Initially administered by the Panama Canal Company under the able direction of James Zetek, since 1946 Barro Colorado Island has been administered by the Smithsonian together with five adjacent peninsulas, as the Barro Colorado Nature Monument (BCNM). The BCNM has an area of 54 square kilometres, perhaps the largest and most studied natural reserve devoted to scientific research in the New World Tropics. The Smithsonian Tropical Research Institute has a permanent research center on the island, dedicated to studying rainforest ecosystems. Because the Island's diverse ecosystem has been very little altered by humans, Barro Colorado has been studied for over eighty years within a great variety of biological disciplines. Only the larger fauna disappeared from Barro Colorado after the lake was flooded in 1914. Many scientific studies have been conducted to document the changes in the species composition of the island (see also Island biogeography). Barro Colorado Island is perhaps the most important biological research station in the New World Tropics.
Every year, an estimated 200 scientists conduct research projects on Barro Colorado Island. "The Tapir's Morning Bath" by Elizabeth Royte chronicles the lives and work of scientists working on the island.