The purpose of the society was to study animals in comparative freedom. In April 1828 the gardens were opened to members. In 1831 William IV presented the royal menagerie to the Zoological Society, and in 1847 the public were admitted to aid funding.
The zoo soon had the largest collection of animals in the world.
Today ZSL is an international scientific, conservation and educational charity. Its key role is the conservation of animals and their habitats. ZSL runs London Zoo and Whipsnade Wild Animal Park, carries out scientific research in the Institute of Zoology and is actively involved in field conservation in other countries world-wide.