A New Zealand zoo revealed Monday that it won't euthanize the tiger that fatally attacked a zookeeper, citing its rarity and its necessity to an ongoing breeding program.

Oz, the Sumatran tiger involved in the incident, killed Samantha Kudeweh, 43, Sunday morning inside the animal's enclosure at the Hamilton Zoo, reported the Associated Press. Kudeweh is a veteran at the zoo, having worked there for more than 20 years. She was also a mother of two children, aged nine and three.

The zoo houses five Sumatran tigers and is owned and operated by the Hamilton City Council. Lance Vervoort, the council's general manager for the community, said in a statement there was always a risk for zoo staff in managing big animals like Oz, but that isn't a reason to put him down.

"Although there is an inherent risk for zoo professionals who manage big cats like Oz, there is no wider ongoing risk. There is no reason for us to put Oz down," he said, according to KTLA 5.

Sumatran tigers are considered critically endangered, with less than 400 of the subspecies alive in the wild on the Indonesian island of Sumatra. This fact was also cited by Vervoort as another reason for why the zoo has decided not to euthanize the tiger, according to Fox News.

"Oz is a significant animal for his species. He is the father of our two cubs, and he is vital to the ongoing breeding program to conserve this rare species."

Vervoort indicated that for now zoo professionals believe the attack was in line with tiger's natural instincts, going on to note that the zoo won't comment on what went wrong until an investigation is completed.

The zoo was closed following the incident, and will reopen Thursday.