Big party for a big Zoo resident

PHILADELPHIA ZOO (WPVI) -- A big birthday celebration at the Philadelphia Zoo Thursday.

Louis the gorilla turned 17 years old Thursday.

There was a big birthday sign in his exhibit at the zoo.

Although Louis seemed a bit distracted, preferring instead to sample all of the birthday treats given to him, including a yam cake.

Louis has been part of the Philadelphia zoo family since 2004.

He's one of five lowland gorillas at the zoo, all of them considered critically endangered.