"Mr. Mom" takes over the care of the 2-year-old after the matriarch passes.

At the Denver Zoo, a male orangutan has taken an unusual motherly role after the death of the family's matriarch.

Last month, Nias, a Sumatran orangutan, unexpectedly died on December 17. She was 32 years old. Nias had two daughters; 10-year-old Hesty and 2-year-old Cerah. On Tuesday, zoo staff members said Nias's father, Berani, had stepped up to take care of the young orangutan.

"In the wild, orangutan males are not involved with their offspring. To see Berani step up as Mr. Mom, is an extremely rare situation—and Cerah couldn’t have asked for a better dad," officials said. "Berani is so attentive and protective of her, seeing to all her needs. He will carry her, comfort her, and even snuggles her when she sleeps."

In pictures taken by zoo officials (below), Cerah can be seen playfully biting on Berani's chin. Berani doesn't seem to mind.

Berani and Cerah, Courtesy of Denver Zoo

It seems Hesty, Cerah's big sister, has also been spending time with the two of them. She can be seen playing with Cerah throughout the day.

"The three of them are sticking together and moving forward," said the zoo.

For more information on Nias and her impact on Denver Zoo and its guests, click here to read her tribute.

What do you think of Berani stepping up as "Mr. Mom"? Have you visited him and Cerah at the Denver Zoo recently? Share your photos/videos with us in the comments.