It is known for being the first zoo to use open enclosures surrounded by moats, rather than barred cages, to better approximate animals' natural environments.

By the 1870s, the trade had proved more lucrative than his fish shop, and Hagenbeck had become one of the most prominent exotic animal traders in all of Europe.

[3] Hagenbeck decided to exhibit Samoan and Sámi people as "purely natural" populations.

He also sought to demonstrate that animals from warmer climates did not need to live in expensive, humid, foreboding buildings.

[8] Using data that he had compiled running his circus, Hagenbeck had estimates of how high and far different animals could leap.

Using this data, he built moats filled with water or an empty pit that he determined the animals could not cross.

In July 1956, forty five rhesus monkeys escaped from the zoo and ran wild in Hamburg.

The incident resulted in calls for help from shocked housewives who met monkeys in their bedrooms and bathtubs.

Some of the monkeys sat in trees and chattered excitedly, showing each other toothpaste, soap bars and bathroom utensils which they had grabbed.

[13] In 1976, the zoo acquired a female Pacific walrus which Hagenbeck named Antje after his sister.

Claimed to be the largest of its kind in Europe, it was gifted in 2002 by the Thai government to celebrate the 72 year anniversary of King Bhumibol's birth as well as the relationship between the two countries.