First-time mother Zayana, the Sumatran tiger at Auckland Zoo, has killed one of her cubs after her other cub died during birth. Photo: Supplied / Auckland Zoo
A Sumatran tiger at the Auckland Zoo has killed one of its cubs just after giving birth.
The four-year-old tiger named Zayana arrived at the zoo in November last year from Topeka Zoo and Conservation Centre in Kansas.
On Friday, the first-time mother gave birth to two cubs, with one of them dying during delivery. Left with only one offspring, the tiger killed the cub overnight.
Auckland Zoo senior keeper of the carnivore team Nick Parashchak said when only one cub was born, it was not unusual for a tiger mother to kill it.
"If there's only one cub, they have to invest in raising it, and that means that they don't get to breed for another two years.
"It's a lot of energy expenditure in that one cub so it's not really beneficial for the survival rate of the species."
He said although unfortunate, the incident was not uncommon in the wild.
"Their natural instincts will kick in, so having only one cub in the wild is not beneficial for the continuation of their genetics and their species, so sadly that cub didn't survive."
Parashchak said that was the first time a cub was killed by its mother at Auckland Zoo.
"These were the first cubs we have had in the last 15 years, but I have experienced similar situations in my previous institutions around the world.
"We do a lot of research into the subject, so we were prepared that this could be a situation where only one cub would be born."
Auckland Zoo team leader Lauren Booth said the team were encouraged to see Zayana's natural instincts come to the fore when she was faced with the challenging situation of giving birth to just a single cub.
"In the wild, the mortality rate for juvenile big cats is high - 50 to 70 percent - and research shows that producing only one offspring creates an even tougher higher-stakes situation.
"Similarly in zoo-based populations, survival rates for a single cub versus multiple cubs are also less successful."
Zayana will soon have a mating cycle with Ramah, the male Sumatran tiger at Auckland Zoo. Photo: Supplied via Auckland Zoo / Kathleen Otto
A tiger mother always wanted to ensure that the two years of effort and resource she needed to invest in raising offspring would benefit her species' population and survival, Booth said.
"Having a larger litter size offers Sumatran tigers the best chance of successfully rearing young, so when only one cub is born - a vulnerable situation, it's not unusual for a tiger mother to kill the remaining cub, which is what has happened here."
Sumatran tigers were listed as 'Critically Endangered' on the International Union for Conservation of Nature (IUCN) list of Threatened Species.
Fewer than 400 of these tigers remained in the wild.
Internally within zoos, there were close to another 400 animals, as part of zoos' global breeding and advocacy programme for this species.
Booth said the tiger would shortly be prepared to have another mating cycle with Ramah, a male Sumatran tiger also living at the zoo.
"While it's sad that this first breeding has been unsuccessful, Zayana has proven she can successfully conceive and give birth, and we observed her demonstrating some positive mothering behaviours towards the first cub prior to the birth of the stillborn cub."
She said despite the death of her cubs, Zayana's health and well-being were good.
"After an exhausting couple of days, she has had plenty of rest and care from the carnivore team, and they report she is now back to her relaxed self - which is great, especially as she will soon have the opportunity to be with Ramah again."
