Editing Philadelphia Zoo Opening (section)

== Evolution and Innovation ==

The Philadelphia Zoo evolved with changing understanding of animal welfare, conservation, and zoo management. Early zoos housed animals in small cages that prioritized visitor viewing over animal comfort; over time, the Philadelphia Zoo pioneered larger, more naturalistic enclosures that better met animals' physical and psychological needs. The zoo participated in breeding programs for endangered species, contributing to conservation efforts that extended far beyond its grounds. It developed educational programs that reached millions of visitors and influenced how Americans thought about wildlife and conservation.<ref name="hanson"/>

In the 21st century, the Philadelphia Zoo introduced Zoo360, an innovative system of see-through mesh trails that allow animals to travel above and around visitors, extending their living space beyond traditional enclosures. Big Cat Crossing, the first of these installations opened in 2014, enables tigers and other large cats to walk through overhead tunnels with views across the zoo. Similar trails were developed for primates, bears, and other animals. The system reflects contemporary zoo philosophy that emphasizes animal wellbeing and engagement while providing visitors with unique viewing experiences. Zoo360 has attracted international attention and established the Philadelphia Zoo as a leader in zoo innovation.<ref name="zsa"/>