The twins were born on Tuesday at Frösö Zoo in Östersund, northern Sweden. They had white fur, something previously unheard of among pygmy marmosets, a type of monkey.
The first of the monkeys, a male, died on Wednesday. Late on Thursday the monkey’s twin sister also died.
Keeper Åke Zetterström said that they may have died because their mother had rejected them. He also told Expressen that albinos are particularly sensitive.
“We’re now hoping to get new white monkeys, who will hopefully cope better,” he said.