Watch: Twin tiger cubs emerge from their den for the first time

CHESTER, England - Two rare tiger cubs born at a zoo in England emerged from their den this week to make their first playful, public appearance. 

The twin female cubs, named Alif and Raya, were born on Jan. 7 at the Chester Zoo, a 128-acre site located about 15 miles southeast of Liverpool, England. The zoo announced their birth in February, saying the new family had spent the past several weeks bonding in their den.

In an update on Monday, the Chester Zoo shared video of Alif and Raya finally venturing outside the den for the first time – engaging in "some playful rough and tumble."

Zoo staff caught the twin cubs having some adorable moments outside under the watchful eye of mom Kasarna. 

The Sumatran tiger cub twins, named Alif and Raya, are pictured after emerging from their den for the first time at the Chester Zoo in Chester, England. (Credit: Provided / Chester Zoo)

Sumatran tigers are the most critically endangered tiger subspecies, the zoo said. They’re only found in patches of forest on the Indonesian island of Sumatra, and only 350 are thought to remain in the wild. 

An increasing human population has seen more than 90% of the Sumatran tiger habitat wiped out, bringing the big cats closer to conflict with villagers, farmers and livestock, the zoo said. 

The species is also heavily poached for its skin, bones and canine teeth, which are sold illegally in traditional Asian medicine markets, the zoo added.

"These majestic animals are hanging on to survival by a thread in Sumatra. They’re one of the world’s rarest tiger subspecies and so to see these two cubs thriving here is absolutely wonderful," Dayna Thain, the Chester Zoo’s carnivore keeper, said in a statement. 

The Sumatran tiger cub twins, named Alif and Raya, are pictured after emerging from their den for the first time at the Chester Zoo in Chester, England. (Credit: Provided / Chester Zoo)

"The cubs are still a little shy and pop in and out of the den with mum Kasarna, but it’s going to be a real privilege to watch as they grow in confidence and their feisty personalities really start to show through," Thain added.

Raya was named after Mount Raya in Sumatra, Alif is a popular name in Indonesia, the zoo said.

Sumatran tigers have webbed paws, which make them "excellent swimmers," the zoo said. The white spots on their ears act as false eyes, making them appear alert from behind. 

There are nine subspecies or types of tigers, three of which are now extinct. The remaining six subspecies include the Sumatran, Bengal, Indo-Chinese, South China, and Amur tigers. 

The Sumatran tiger is the smallest of all tiger subspecies, the zoo said.

This story was reported from Cincinnati.