Sumatran tiger Zayana due to give birth early January

We’re delighted to share that a recent ultrasound has provided our carnivore and veterinary teams with 100 percent confirmation that Sumatran tiger Zayana is pregnant!

Now in the last few weeks of her approximately 15.5-week (108-day) pregnancy, all going well she is due to give birth around early January.

As we shared with everyone at the time, Zayana came into oestrus (her receptive period to breed) in late September enabling her and male Ramah to once again come together to mate.

“While we had behavioural and physical pregnancy indicators such as Zayana not coming back into oestrus in late October, her subsequent weight gain and some other physical changes, it’s fantastic to now have this diagnostic evidence,” says Carnivore team leader Lauren.

“Our ability to do an ultrasound is based on Zayana’s voluntary participation in our tiger training programme. It’s a programme that we’re constantly evolving which enables us keepers and the vet team to do a range of regular physical health checks with her without requiring any sedation and in a way that’s really easy, comfortable, and stress-free for her.

“From this ultrasound, it’s not possible to confirm how many cubs Zayana will have, but it gives us and the vet team confirmation that her pregnancy is tracking well,” explains Lauren.

Lauren says now that Zayana is in the final month of her pregnancy, she’ll gain more weight (additional to the 4kg she’s already put on) and will spend more time resting and sleeping, and she and the team will continue to monitor her closely.

“Zayana is a very calm, confident, and relaxed cat, and everything is proceeding really well at this stage, but she still has a long way go; she needs to get through the rest of her pregnancy, successfully give birth to, and then rear, healthy cubs. We’re hopeful that this time around will be smooth sailing, but as experienced animal professionals we are always very aware of the range of risks involved with any pregnancies and births."

“As research shows and as we’ve already experienced with Zayana, mortality rates are high (50% - 70%) when big cats have small litters, and a mother must decide whether or not to invest the two intensive years required to raise offspring, and not have the opportunity to breed again during this time,” says Lauren.

While Zayana’s first breeding in September wasn’t successful, Lauren and team are encouraged by the fact that she successfully gave birth, and they also got to observe some positive mothering behaviours towards the first cub prior to the birth of a stillborn cub.

“Our job is to be prepared for every possible scenario so that we can support Zayana to be as successful as she possibly can, and we are. We hope this will result in her and Ramah contributing valuable new genetics to enhance and help sustain the international zoos’ breeding and advocacy programme for this critically endangered big cat that’s facing so many challenges in the wild.

“The Sumatran tiger is such an incredible species that we feel so privileged to work with and enable our visitors to experience – and in doing so, join us in supporting critical mahi with our conservation partners to conserve these big cats in Sumatra.”

We look forward to sharing more news about Zayana in the coming weeks!

Background:

• Auckland Zoo’s Sumatran tigers: Male Ramah (6) from Oklahoma City Zoo and female Zayana (4) from Topeka Zoo and Conservation Centre (Kansas) arrived at Auckland Zoo in early November 2022. With their arrival came a breeding recommendation from the World Association of Zoos & Aquariums (WAZA) Global Species Management Plan (GSMP) for Sumatran tigers, who bring valuable new genetics to enhance and sustain the Australasian region’s population for this Critically Endangered big cat species.
• Breeding: Female Sumatran tigers reach sexual maturity around 3-4 years of age, and males at 4-5 years. Females come into oestrous every three to nine weeks, and following conception, have a 100 – 108-day gestation before giving birth. Average litter size is 2-3 cubs, which the female rears alone. In the wild, there can be between 200-250 matings over the course of the female’s receptive period (between 4-7 days) as cats are induced ovulators – requiring the multiple stimulation for ovulation to occur.
• Rearing newborn cubs: Just as in the wild, in a Zoo environment a tiger mother can keep her cubs in a secluded space – potentially for up to 12 weeks (3 months), or until she determines it is safe for them to be out and seen.
• Conservation status: The Sumatran tiger is listed as ‘Critically Endangered’ on the International Union for Conservation of Nature (IUCN) list of Threatened Species. Fewer than 400 of these tigers remain in the wild. Internally within zoos, there are close to another 400, as part of zoos’ global breeding and advocacy programme for this species.