A polar bear at Berlin Zoo has given birth to her third son.

Tonja gave birth on 1 December, and the park has released images of her newest arrival cosying up to her mother in their habitat.

According to the park, Tonja had been sleeping for 22 hours a day up until the birth. She had put on extra fat during the pregnancy, going up to 390kg (859lbs) from 230kg (507lbs).

Image: The cub is seen on its mother's chest

The cub has been described as being the size of a guinea pig.

It comes after Tonja lost two infants, a 26-day-old in January who had not been named, and her four-month-old Fritz, who died of hepatitis last year.


Dr Florian Sicks, from the zoo, watched the animals soon after the birth from a camera inside Tonja's enclosure.

Image: Tonja has given birth to a cub

She said: "When around 9pm on 1 December, loud smacking noises were heard for the first time for a long time, my first tension eased a bit.

"Meanwhile, the polar bear cub regularly drinks and approaches a rhythm of about 2-3 hours."

The zookeepers suspected she was pregnant but because of the animal's size and their reputation as land protectors, sedating her to get an ultrasound was too risky.

The cub's father is a polar bear called Volodya.

Image: Visitors will not be able to see the bear for the first few days at least

Zoo director Dr Andreas Knieriem said: "In the first 10 days, the mortality rate is particularly high, but we are very confident and keep our fingers crossed.

"Tonja has always looked after her cubs so well and she does it again. Thanks to the camera technology, I too - even from home - can be there again and again live and watch the two in their casting cave."

No one will approach the cave where Tonja and her cub are for the next few weeks to allow her to rest. The bears will probably first come out into the open in the spring.

Zookeepers are particularly happy with so many arrivals since the death of Knut in 2011.