Denver the giraffe is hitting a big milestone Friday, Feb. 1, and all of Tucson’s invited to her big party. Kicking off at 10 a.m, the zoo crew will welcome the public. The first 20 people in line at the event get to feed Denver a birthday biscuit.

The zoo keepers already celebrated the big day Thursday, Jan. 31 with browse laid out to read “30” and a giraffe biscuit cake holding 30 birthday carrot "candles."

Reid Park Zoo first met Denver back in 1990, when she first arrived just before her first birthday. Denver has since been a mom to four calves—two boys and two girls.

“Denver doesn’t know she’s a giraffe," said Reid Park Zoo Keeper Kelly. "Giraffes are skittish and very cautious by nature, but Denver will come right up to you. She’s very curious.”

According to the zoo, the median life expectancy of a female giraffe is 25. At 30, Denver is just a couple of months younger than the oldest giraffe in the nation. To keep Denver in her old age, her Keepers feed her high calorie food with lots of vitamins, and weigh her twice a week to make sure she's maintaining her weight. Denver's mother lived to be an estimated 32 years, so longevity seems to be a family trait.

In the giraffe habitat, guests can tell Denver apart from her companions because she is the smallest giraffe at the Zoo. Her spots are entirely filled in and she has a spot in the shape of an upside down heart on one of her shoulders.

The Reid Park Zoo is located at 3400 E. Zoo Court, and opens at 9 a.m.