The Houston Zoo celebrated Mother's Day with Cheyenne the orangutan.
Cheyenne's maternal instincts led her to adopt two-month-old Aurora after the baby was rejected by her own mother.
Zoo officials said orangutan mothers and babies have an incredibly close relationship. Baby orangutans don't have a support network around to give them the many lessons of finding food, building nests and other survival skills. Their mothers teach them everything about survival in the forest before they set out on their own.
Sunday was also Cheyenne's 40th birthday. The zoo filled her habitat with wrapped presents filled with treats.
Cheyenne and Aurora are lending their image this year to MOM, the Missing Orangutan Mothers Campaign of Orangutan Outreach. The MOM Campaign is working to bring attention to the crisis facing the world's orangutans and encouraging people to help protect them.