Surabaya Zoo performed on the animals found plastic and wood inside the animals. The death of Melani the tiger, one of only a few hundred Sumatran tigers left in the world, outraged animal activists when it was discovered that the tiger was suffering from extreme digestive disorders before being rescued from the zoo. On 28 January 2014 Surabaya Zoo authority announced that the zoo has a collection of 3,459 animals from 197 species, but 81 animals are sick, disabled, and old, and 44 of which are in severe conditions. An online petition that calls for the closure of Surabaya Zoo due to
Phoenix Zoo animal husbandry and research projects for selected species that are in need of conservation efforts. In its first years, the zoo hosted a captive breeding program ("Operation Oryx") with the specific goal of reintroducing the almost extinct Arabian oryx to the wild. By the early 1990s this program was still one of only two programs (the other being the golden lion tamarin) to have gone through the full wilderness-zoo-wilderness sequence. Nine oryx had been caught or donated for the breeding program. However, two pairs were delayed, so the "World Herd" was started in Phoenix in 1963 with only five animals