The Egyptian fascination with keeping exotic animals was two-fold. Firstly, there was a desire to utilize wild animals for practical purposes, perhaps even resulting in domestication. This approach was predominately aimed at addax, gazelles, and other antelopes, but also included hyenas (for use as hunting animals) and lions, for use in war. That none of these efforts ended up succeeding doesn't mean that the idea behind them was one resigned to antiquity - throughout the 19th century, additional efforts were resumed by Europeans and North Americans.
The second aspect of Egyptian zookeeping was a religious one. The Egyptians were famed for their fondness for cats, but animal worship extending far beyond that. Look at the pantheon of Egyptian gods and you'll see a zoo-load of animals... or at least the heads of a zoo. From the jackal-headed Anubis to crocodile-headed Sobek, many of their gods had the heads of animals. The result was a worship of living animals as representations of the gods, with animals being cared for my priests in temples, often being mummified after death.
A mummified Nile crocodile, on display at the St. Augustine Alligator Farm and Zoological Park
The climate and landscape of Ancient Egypt is far different from that of modern Egypt, and animals such as hippopotamuses, crocodiles, and lions could be found where they are now absent. That being said, stocking a menagerie worthy of a pharaoh and his court required beasts more sensation that those found in their backyards. As early as the fifteen century BC, Queen Hatshepsut sent out what may have been the first zoo collecting expedition down the coast to Somalia, returning with monkeys, leopards, and a giraffe. Other animals were brought in as tribute or sent out as gifts to other rulers. In 1100 BC, the pharaoh sent a crocodile and a hippopotamus as a gift to Tiglath-Pileser I, King of Assyria.
As Egyptians encountered other cultures through conquest and trade, the zookeeping tradition developed as well. When Alexander the Great added Egypt to his empire, he left one of his generals, Ptolemy, to rule, giving rise to the Ptolemaic Dynasty, which ended with the suicide of Cleopatra. In a parade in Alexandria to celebrate the feast of Dionysus, elephants, ostriches, and antelope paraded down the streets, while carts contained cages of peafowl, parrots, and other birds. As described by James Fisher in his Zoos of the World:
"The people of Alexandria with a taste for 'more exciting' animals were not disappointed. The procession included 24 lions, 14 leopards, 16 [cheetahs], six pairs of one-humped camels, a 'white bear', a giraffe, a gigantic snake said to be 45 feet long, and, wonder of wonders, a rhinoceros."
Like many wonders of the ancient world, the menageries of Alexandria is gone. Even more unfortunately, most the wildlife in the former Egyptian Empire is also gone. Every year the Sahara pushes further south, and the wildlife of Africa becomes increasingly isolated within smaller protected areas. With the current political situations in North Africa, it is unlikely that anyone is going to be making wildlife conservation top priority anytime in the immediate future. Only by remembering what was lost, however, can there be hope of recreating a better future for animals - and people - in Egypt.