The earliest collection of animals, though not a public zoo, was established by Shulgi, ruler of Ur (now Southeast Iraq), around 2400 B.C.
Queen Hatshepsut of Egypt collected animals from all parts of Africa and established the first real zoo in 1500 B.C. Chinese Emperor Wen Wang followed her example in 1100 B.C., when he built an enormous zoo to display his wealth and power. This zoo, named The Garden of Intelligence, covered about 1500 acres and contained animals from all parts of his empire.
Large collections of birds and mammals were also kept in public zoos by the ancient Greeks, so that their students could study animal life. The ancient Romans brought animals from the foreign lands they had conquered and kept them in private zoos. They used many of the wild animals for bloody fights with slaves and prisoners in the Coliseum.
Although interest in zoos declined in Europe for several hundred years, exploration to the New World renewed that interest, and new zoos were established. A zoo built in Vienna in 1752 by Emperor Franz Josef for his wife, Maria Theresa, is the oldest zoo still in existence.
The San Diego Zoo in California has the largest collection of animals in the world today, 5,100 animals!