Perth Zoo's massive matriarch turns 59

Perth Zoo's matriarch has been treated to a fittingly large birthday celebration, with staff preparing a giant cake for the 59-year-old Asian elephant.

Tricia, who arrived at Perth Zoo from Singapore in 1963, was presented with a three-tiered bran cake, decorated with frozen fruit juice and iced with her favourite peanut butter.

The zoo's senior citizen, named after 1962 Miss Australia Tricia Reschke, is beginning to show her age according to senior elephant keeper Kirsty Carey, but remains a staff favourite.

"To help with some age-related niggles, Tricia receives deep tissue massages with the assistance of an equine massage therapy backpack," Ms Carey said.