Nikko the white-handed gibbon received the best Christmas present ever -- a new blonde-haired mate named Gladys who is 18 years younger than he is.

Nikko, 30, lost his longtime mate to illness this past year at the Oakland Zoo, and keepers noticed that his normally cheerful behavior had changed. Nikko's early morning songs became silent after his mate's death.

Gibbons mate for life and are monogamous, so when 12-year-old Gladys needed to be relocated from the Gladys Porter Zoo in Brownsville, Texas, arrangements were made to move her to Oakland to help console the grieving Nikko.

Zoo officials say the pairing is going well so far; the two have groomed each other, hugged and had about 30 days to get acquainted in their night house where they could see each other but not touch.

They were recently introduced in their Gibbon Island habitat and things have gone well.

"It took about 10 minutes to get to know each other and they've been together ever since," said primate keeper Dannielle Stith. "They groom each other and sing together."

Gibbons are lesser apes and are found in Indonesia, Laos, Malaysia, Myanmar, Thailand and northern Sumatra. They are currently listed as endangered due to deforestation and pet trade. Gibbons can live 30 to 40 years in captivity, but less in the wild. They weigh from 8 to 17 pounds and are about 3 feet tall. Gibbons eat mostly fruit, but sometimes leaves, insects or vegetables.

Nikko and Gladys can be seen in their habitat at the Oakland Zoo, where they appear to be living happily ever after surrounded by a moat.

Jane Tyska is a multimedia photojournalist based in Oakland. Follow her at Twitter.com/tyska.