Auckland Zoo has announced its Sumatran female tiger is six weeks pregnant - only the second time in the zoo’s history that there has been a breeding pair of tigers.

Four-year-old Zayana from Topeka Zoo and Conservation Centre in Kansas arrived at Auckland Zoo in early November 2022, along with 5-year-old male Ramah from Oaklahoma City Zoo.

The zoo keepers had suspected Zayana was pregnant after two mating introductions with Ramah in May but it was only through a recent ultrasound they could confirm it.

The zoo said introductions were made after months of planning, and intensive monitoring and management at a time when their behaviours indicated they were very keen to be together.

Signs from Zayana in the pair’s mating period included lots of chuffing and calling, increased face pressing up against the mesh barrier that separated the two tigers, and a desire to sleep as near as possible to Ramah.

Carnivore deputy team leader Nick Parashchak said the ultrasound on Tuesday confirmed what they thought.

“Because of the relationships we’ve all built with her, Zayana is really trusting of us. She enjoys and is very co-operative and focused during training where she has choice about participating and is rewarded with treats like meat and pet milk - which she loves.”

But the team were cautious about the challenges of birth and demands that came with being a first-time mum, Parashchak said.

“Research shows that there are risks associated with litter sizes. For example, when there’s just one cub born, there’s a higher chance of mismothering as opposed to being more invested in caring for multiple cubs.

“We won’t know how many cubs Zayana will have until she gives birth, but for now we’re doing everything we can to support her to have the best possible pregnancy.”

The zoo keepers described her as being a lot more relaxed, spending more time sleeping and resting and choosing not to go outside as much as she normally would, and being exceptionally chilled and chatty towards her carers.

“It’s been a very exciting journey with Zayana and Ramah since they arrived from the USA last November. For all of us, except for Lauren, this is our first time working with a pair of breeding tigers,” Parashchak said.

“We have a really supportive wider zoo community so there’s been lots of knowledge sharing and online discussions with our American colleagues and our colleagues at Adelaide Zoo, who had tiger cubs early this year.”

With a gestation period of 100-108 days, Zayana is now a little under halfway through her pregnancy.

She is expected to give birth in September, but it will not be until closer to Christmas before she will be able to bring her cub(s) out into the zoo’s South East Asia Jungle Track’s lowlands habitat.

- RNZ