Due to the consequences of World War I, ever increasing subsidies by the government were needed to keep the zoo open.

Two years later, in 1924, due to public pressure and private commitment by the animal trading company Firma Ruhe, it was re-opened with a lions' canyon and monkey rock.

As time passed and with funding from the municipal budget, new enclosures were built for rhinos, elephants, giraffes, antelopes, seals, and penguins.

In 2005, the Winter-Zoo was introduced, in 2007, the children's paradise Mollywoop was opened, in spring 2010, the Australian Outback and in May 2010, the seventh theme world followed.

A 5-kilometre-long (3.1 mi) explorer path leads through the different exhibits: Hanover Zoo is also involved in conservation efforts through multiple programs: