In 1950 the US government sent military advisers to train tribal police along the border of Thailand.

Among them was Harold Mason Young, son of American missionaries, who had been born in Burma.

The zoo was expanded to its current 200 acres (81 ha) footprint, transferred to the Zoological Park Organization under Ministry of Natural Resources and Environment, and opened as the official zoo of Chiang Mai province in 1977.

[1][2] Chiang Mai Zoo is privately operated and includes a large variety of animals.

Overall, 400 animal species are represented in the zoo including Humboldt penguin, Cape fur seal, koala, Indian rhinoceros, hippopotamus, greater flamingo, gaur, red-shanked douc, Bornean orangutan, African spurred tortoise, Asiatic black bear, Malayan sun bear, giant anteater, Indochinese tiger, Barbary sheep, Malayan tapir, and many types of reptiles.