Gus, who was named Augustus following a public vote, is a western lowland gorilla and was the first of its species to be born at the zoo to first-time parents Gracie and Elmo in December 2015.

“Western lowland gorillas are listed as critically endangered by the International Union for Conservation of Nature (IUCN) due to hunting and disease,” the zoo says.

“Gorillas also have an alarmingly low reproductive rate (at an observed rate of 3 percent population increase), so even if there was a drastic decline in hunting and disease, it could take at least 75 years for population recovery to occur in optimistic scenarios.