Animal conservationists have described the moment a rare tree kangaroo was seen emerging from its mother's pouch as "celebratory".
The joey, the first of the endangered species to be born at Chester Zoo, arrived in July and has since been developing in the pouch.
Unlike its famous Australian counterpart, the shy Goodfellow's species live in trees, the zoo said.
Zookeepers now had a "unique position" to record its development, it added.
David White, team manager at the zoo, said the Goodfellow's tree kangaroo species, native to Papua New Guinea, had "one of the most complex birthing processes in the animal kingdom".
"When a joey is first born it's only the size of a jellybean and is incredibly underdeveloped," he said.
"Moments after the birth, with eyes still tightly closed, the joey knows to instinctively crawl up mum's belly and into her pouch - following a channel which she has marked out by licking her fur."
The baby receives its nutrition while it grows for six months in the pouch until it "starts to pop its head out", he added.
The joey is expected to fully emerge from the pouch soon and start hopping around and learning to climb trees.
"That's when we'll be able to determine if it's male or female and give the youngster a fitting name," Mr White said.
Conservationists have been recording the joey's growth with a special endoscope camera that has been placed in the mother's pouch every few weeks.
They say the data could help tree kangaroos and other threatened species.
Mr White said Goodfellow's tree kangaroos were often hunted for their meat while their habitat is disappearing, as forests are cleared for timber and to make way for coffee and rice plantations.
The zoo said it was working with communities in South East Asia to boost sustainable farming practices and prevent further deforestation.