Dugongs

1 Ladies of the Sea

The word 'dugong' derives from the Malay duyung, meaning 'lady of the sea'. Other common aliases for dugongs include 'sea cow', 'sea pig' and 'sea camel'. "Dugongs are actually closer related to elephants and hyrax, a type of guinea pig," says Barnes.

2 Holy (sea) cows

Dugongs are mentioned in the Bible in Exodus 25:5 and 26:14 and also in Numbers. The hides of dugong (aka tachash) are believed to have covered the Tabernacle, the portable tent dwelling for the Holy Spirit built by Moses in the 10th century BC.

3 Fussy eaters

The dugong is the only strictly herbivorous mammal in the sea. "Pig and Wuru are fed English spinach, pak choy, endive, chum soy and cos lettuce and will eat up to 40kg of leaves every day," says Barnes. "That's 20 per cent of Pig's total body weight!"

4 No mermaids

The Dugong is the original 'siren' of the sea, being one of four living species of the order Sirenia that once flourished worldwide. Greek and Roman mythology spoke of sirens as water nymphs that charmed sailors to sleep with their songs then tore them to pieces. In later centuries, ancient mariners mistook dugongs for human women, the origin of "mermaids". Pig is stridently masculine though, says Barnes. "He's a typical maturing male - and his domineering, sexually charged behaviour is very unladylike."

5 Old favourites

In 1959, a 5,000-year old wall painting of a dugong drawn by Neolithic peoples was discovered in Tambun Cave, Perak, Malaysia.

6 Famous five

Most Dugongs live in the northern waters of Australia between Shark Bay and Moreton Bay. Pig and Wuru are the only dugongs in captivity in Australia and two of just five on exhibition around the world. The pair was rescued several years ago after being found stranded and malnourished off the coast of Queensland and, despite repeated attempts to release them, were considered unable to survive in the wild.

7 Showoffs

During the Renaissance and the Baroque eras, dugongs were often exhibited in wunderkammers ('wonder rooms' or 'cabinets of curiosity') in sideshows where they were billed as 'Fiji mermaids'. Barnes says that Pig is a flagrant exhibitionist. "He plays with boat buffers, buckets and witches' hats. He even wears a doormat like a Superman cape."

8 Big girls

Dugongs reach an average length of 2.7 metres and a weight of 250 to 300kg. Females tend to be larger than males: the largest known specimen, a female from off the Saurashtra coast of west India, measured four metres and weighed a tonne.

9 Delayed adolesence

Dugongs live for 50 years or more. Females give birth only a few times in their lives after a gestation period of 13 months. They are highly nurturing mothers, only weaning their babies after two years. It is then a further eight to 18 years until they become sexually mature.

10 Dugong Love

Barnes doesn't want Pig, 10, and Wuru, 4, to procreate, although Pig's oncoming maturity means it's a possibility. "It'd be cute, alright, but there'd be no possibility of returning a calf born in captivity to the wild. And we'd go through a helluva lot more lettuce."