Tiger joy! Zoo lets closely-guarded secret slip at last by announcing birth of four rare critically endangered cubs

A  zoo has let slip that four tiger cubs from a critically endangered species have been born, after keeping it a closely guarded secret for weeks over fears they wouldn’t survive.

Officials at the Wroclaw Zoo in the southwestern Polish city of Wroclaw said the Sumatran tigers – whose numbers have dwindled to around 400 in the wild – were born on July 22.

But the zoo chose not to go public with the news until they could grow, gain some strength and be vaccinated, zoo spokesperson Weronika Ysek said.

Each cub is now about double the size of a domestic cat, at over 18 pounds (8 kilograms) each.

Sergiusz Kmiecik, acting president of the zoo, which has been breeding Sumatran tigers since the 1960s, said: ‘The joy is even greater that all four tigers are developing healthily, are active, eager to eat and play with each other and with their parents.’

The four cubs are the offspring of mother Nuri and father Tengah, who four years earlier produced a female, Surya 

Each cub is now about double the size of a domestic cat, at over 18 pounds (8 kilograms) each

Tigress Nuri with one of the four tiger cubs at the Wroclaw zoo. The cubs are currently unnamed

Sumatran tigers – the most critically endangered tiger subspecies – are under increasing pressure due to poaching and their shrinking jungle habitat

A view of two of the young Sumatran tiger cubs feeding from their mother who is laid down

The zoo is also celebrating that the litter included three males and one female. The males may help balance out the zoo population

The Polish zoo proudly hailed the birth of the litter as ‘a breeding success on a global scale’

The zoo, located in the southwestern Polish city of Wroclaw, has been breeding Sumatran tigers since the 1960s 

The four cubs are the offspring of mother Nuri and father Tengah, who four years earlier produced a female, Surya.

She currently lives in a zoo in Cottbus, Germany.

The zoo proudly hailed the births as ‘a breeding success on a global scale’.

Pawe Sroka, the head of the zoo’s department of predatory mammals, noted that Tengah had stayed with the cubs from the beginning, which is rare for tigers.

He said: ‘He was calm, gentle, and even helped Nuri with care, learning how to `handle’ the cubs.’

The zoo is also celebrating that the litter included three males and one female.

Females predominate in European zoos, so the birth of three males can help balance their population.

It is not yet clear where the four cubs will end up going, and they still have a lot of growing to do before that is decided, Ysek said.

They also haven’t been named and the zoo is considering letting the zoo’s visitors and fans take part in their naming.

Sumatran tigers – the most critically endangered tiger subspecies – are under increasing pressure due to poaching and their shrinking jungle habitat.

There are only about 400 of them left in the wild, according to the Wroclaw Zoo, which also has a foundation that works to support their protection.