The rare colobus monkey named Delu at the Oregon Zoo is turning one year old and zookeepers organized a celebration.

Oregon Zoo Photo

Mali holds her new baby close.

Delu has done extremely well her first year of life, according to Africa Keeper Liz Zimmerman, and she has achieved several milestones. The young colobus has weaned herself from her mother's milk and already lost her pure-white baby coloring. She is now a striking black-and-white, similar to her parents.

Zookeepers were throwing a party for Delu on Friday, Dec. 21. Visitors can learn more about the rare monkey during a zookeeper chat at 10:30 a.m.

Zimmerman said Delu is very independent and fits in well with her zoo family.

"She spends her days wrestling with her parents, Mali and Kiku, or 'Aunt' Zoe, while exploring her habitat. She also grooms the adults, which is an especially important behavior for these social animals, because it helps strengthen their relationships," she explained.

Delu is the fourth baby, and first female, mother Mali, 11, and her mate, Kiku, 16.

"We chose the name Delu, because it is a Hausa word for 'the only daughter,'" says Zimmerman. Hausa is the native language for the majority of Nigeria, and is prominent across West Africa and in Ghana.

The colobus monkey is a threatened species in the wild and continues to lose habitat as humans cut down forestlands. The rare monkey is also hunted and killed -- for the bushmeat trade and for its beautiful fur, or captured and sold as part of the illegal pet trade.