Europe's second walrus born
LONDON, England (CNN) -- Walrus 'Olga' has had only the second calf of its type to be born in captivity in Europe -- eight years after she gave birth to the first.
'Olga,' who was rescued after becoming stranded on the U.S. coast, gave birth to 'Boika' at the Dolfinarium Harderwijk sea mammal park in the Netherlands on Sunday.
It came eight years after she had 'Nikolai' at the same center.
"She has done very well," Willamin Eggengoor from the Dolfinarium Harderwijk park told CNN.
"She is doing fine. Mother and calf are very tired. They are sleeping almost hand in hand -- which is good."
'Boika' is believed to be only the second Pacific Walrus to be born in Europe outside of the wild.
Walruses do not have large families, and the five at Dolfinarium Harderwijk are unusual.
"We are one of the few parks that have walruses. We have a group, which is unique," Eggengoor added.
"Most places have one or two, we have five," she added.
All the herd have been given Russian names to reflect the species' origin.
Boika, meaning 'fighter,' weighed in at 50 kilos. He is already one meter long and sporting a large moustache.
The baby walrus will stay at the park and be raised by Olga, who is unable to be returned to the wild because of poor eyesight.
"We are leaving the baby with its mother. Most parks take calves away -- but we don't," Eggengoor said.
A new enclosure is being built for the growing family, due to be completed in 2005.
Dolfinarium Harderwijk is the only park in Europe where there have been two successful walrus births in captivity.
Adult male walruses can weigh close to two tons -- about the weight of a pickup truck and can grow up to 14-feet long.
The large pinnipeds, related to seals and sea lions, eat up to 7 percent of their total body weight per day.
Calves are born with ashen gray with short, soft fur. Within days, the calf becomes more robust and its fur turns reddish-brown.
A calf grows about 15 cm in length each month. In a zoological environment, a calf gains 0.7 to 0.9 kilos per day.
The gestation period of a walrus is 15 months.