Oz aquarium's dugong fete

The Sydney Aquarium celebrates 21 years of operations, with two rare marine mammals.

The Sydney Aquarium turned 21 on Thursday and celebrated with the aid of two favourite residents, Pig and Wuru.

Pig, a 10 year-old male, and Wuru, a 4 year-old female, are both orphaned dugongs cared for by aquarium staff.

Anniversary treats included special dugong-friendly presents and a unique birthday cake made of lettuce.

Dugongs are marine mammals like the Manatee, which inhabits parts of North and South America, as well as Africa, believed to have been mistaken for mermaids by sailors.

As a result, they have been given the scientific name Sirenia, after the beautiful Sirens of Greek mythology.

With a conservation status of "vulnerable", there are less than 10 captive dugongs in the world.

The presence of two of the precious animals at the Sydeny aquarium made them the obvious choice for the celebration.

So there was no better way then to do it with dugongs.

Puja Bharwani, Reuters.