Hertha was born in 2018 to Berlin Zoo resident Tonya and Volodya, now residing and spreading his genetic code in facilities in the Netherlands, who were brought together to breed.
However, it has now been revealed that Volodya and Tonya are actually brother and sister, meaning the cub named after one of the city's football teams is the product of incest.
How was this revealed?
Parents Volodya and Tonya both came from the same breeding program in Russia. Moscow Zoo biologist Marina Galeshchuk noticed a disparity in Tonya's old documents last year, prompting further investigation.
Introducing Berlin's new baby polar bear
Berlin's Tierpark has welcomed a new family member, a polar bear cub. Born to mother Tonja, the little cub charmed Tierpark visitors during her first public appearance.
Image: picture-alliance/dpa/B. Pedersen
Hello world
Berlin's Tierpark presented its latest addition on Saturday, a brand new baby polar bear. Nine-year-old mother Tonja and her cub, who is still to be named, made their first public appearance together with mom keeping a close eye on her baby as she explored the outdoors for the first time.
Image: picture-alliance/dpa/B. Pedersen
Under mom's paw
The first few months of the cub's life were spent in darkness with her mother. Baby polar bears are born deaf and blind and need intensive care from their mother when they are first born. Zoo directors have said the cub's name will be determined in collaboration with potential future adopters.
Image: picture-alliance/dpa/P. Zinken
Like mother, like daughter
The zoo's polar bear keeper, Florian Sicks, said the bond between the two was very close. "Tonja is a very good mother, taking incredibly good care of her cub, never letting her out of her sight. We can't complain."
Image: picture-alliance/dpa/B. Pedersen
A new celebrity
There was quite a turn out for the cub's first public appearance. Many photographers came to capture the baby polar bear's first steps outdoors and they weren't disappointed. The cub provided the crowd with plenty of picture-perfect opportunities.
Image: picture-alliance/dpa/P. Zinken
Putting on a show
The cub must have known the cameras were for her. She ran around the enclosure and rolled on the ground, absorbing her new environment. She even took a quick dip for the paparazzi.
Image: picture-alliance/dpa/P. Zinken
'Love you, mum'
The cub's mother Tonya sadly lost three cubs in the past two years. The mortality rate of polar bears is very high during the first three months of life. Male polar bears don't play a large role in the lives of their young — the cub's father, Wolodja, lives in a zoo in the Netherlands.
Image: picture-alliance/dpa/P. Zinken
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It transpired that Tonya had been mixed up with another female born at around the same time. The mix-up was confirmed by genetic analysis.
Galeshchuk has been the coordinator of the European Conservation Breeding Program for polar bears since summer 2020.
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How has Berlin reacted?
In a statement from the zoo and the animal park, she is quoted as saying, "If we had known about the relationship between Tonya and Volodya, we would of course not have recommended the two polar bears for breeding. That was a mistake."
Tierpark director Andreas Knieriem said it was a case of human error and that there was no ill will towards Moscow. He said the Moscow Zoo staff had been fully transparent.
"This serious mistake is a regrettable setback for the careful work undertaken by the European breeding program."
Tonya has now been banned from having any more children because her parents' lineage is already very strongly represented within the European captive breeding program.
The mother and cub will stay in Berlin for the time being.
Tonya was mixed up with another polar bear when she was in quarantine in RussiaImage: Kira Hofmann/dpa/picture alliance
Did anyone know about this?
The inbreeding should not affect Hertha's health, according to experts.
When the two bears arrived in Berlin in 2013, some people raised suspicions that the two were siblings, however, the zoo rejected these theories, according to James Brückner from the German Animal Welfare Federation.
He said the mix-up was a "disaster for the already questionable breeding efforts for polar bears in zoos" and called on zoos to stop keeping and breeding polar bears.
Polar bears are listed as "vulnerable" on the IUCN Red List on the basis of their declining habitat, but not as endangered. Between 20,000 and 31,000 are thought to be left in the wild.
aw/msh (dpa, AFP)
The plight of the polar bear
Polar bears are one of the most well-known icons of the environmental movement. On International Polar Bear Day, DW takes a look at how the world's largest land carnivore is holding up in the warming north.
Image: picture-alliance/dpa/Keystone
Black and white
Despite outward appearances, a polar bear actually has black skin. They only appear white because of highly reflective, translucent fur around 2.5 to 5 cm (1-2 inches) thick. The fur, along with an insulating layer of fat, helps keep them warm in frigid Arctic conditions. To keep from slipping on the ice a polar bear's foot is covered with small, soft bumps that create friction.
Polar bears rely on marine fat, or blubber, to stay alive. Their main source: seals, which they hunt on sea ice in the winter months to store energy for summer and fall, when food can be scarce. They can put away as much as 45 kilograms (100 pounds) in one meal. But with sea ice now melting earlier and forming later in the year, bears are spending longer periods without food.
Image: picture-alliance/Arco Images/H. Schouten
Born in snow
Food scarcity can cause birth rates to drop in unhealthy bears and cubs can die from a lack of fat on nursing mothers. Most females give birth once every three years, digging their dens in early winter and waiting for the snow to cover the entrance before giving birth — largely to a litter of one or two cubs. The mother and her young leave the den and head toward the sea ice in March or April.
Image: picture alliance/blickwinkel/F. Poelking
A (mostly) solitary life
A cub will spend the first two to three years of its life with its mother. During this time the mother will be fiercely protective. Eventually though, she will chase them away or abandon them, leaving them to fend for themselves. Besides brief encounters during mating season, polar bears will then spend most of their lives alone — although they may occasionally share a large kill with other bears.
Image: Polar Bears International/BJ. Kirschhoffer
Nap time
Unlike other bear species, polar bears don't hibernate. With the exception of pregnancy, when a female polar bear remains in her den until her cubs are large enough to survive outside, they stay active all winter while food is plentiful. But they're happy to take a nap whenever a snowstorm hits. They can even remain in one place for hours while the snow piles up around them.
Polar bears are native to the Arctic and can be found in Russia, the US, Norway, Greenland and Canada, which is home to around two-thirds of the global population. They spend much of their time on the ice hunting and breeding. But as the world warms the northern ice cap retreats, threatening their habitat.
Image: Polar Bears International/Kt. Miller
Bear vs. human
With loss of their ice habitat, polar bears are increasingly coming in contact with humans. People in settlements around Canada's Hudson Bay may run into the bears, typically young adults — inexperienced hunters — and mothers with cubs at dump sites, where they scavenge for food. In Churchill, Manitoba, authorities have built a jail where nearly 30 polar bears can be held before being relocated.
Today there are roughly 22,000 - 31,000 polar bears left in the wild, and the population is considered vulnerable. In addition to habitat loss, the bears are also threatened by unsustainable hunting and industrial development, which includes offshore oil and natural gas exploration. Some estimates suggest polar bear numbers will decline by more than 30% in the next 30 years.
