The Maryland Zoo's four-year-old giraffe, Kipepeo, gave an unexpected birth to a healthy baby giraffe March 27.

Maryland Zoo said there is no record of Kipi breeding before she arrived to Maryland. Giraffes sometimes don’t visibly show when they are pregnancy in part due to their large body size, zoo officials said, adding that a hormone analysis is usually needed to detect a pregnancy.

Keepers at The Maryland Zoo in Baltimore said no one knew that Kipi, a 4-year-old reticulated giraffe who arrived at the zoo in November, was pregnant.