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INTRODUCTION

The Dugongles of Humpybong Village have been created as a fun and informative way to reach young people’s hearts and imagination; especially on issues of our local and wider environment.

Our Family is gentle, funny, mischievous, and sensitive, it has lots of friends and visitors that bring with them a host of oddball characters and situations that help to highlight environmental problems.

This is an awareness programme, not a donation seeking exercise or appeal on behalf of any particular environmental organization or group.

If the exploits of our Dugong Family generate sufficient interest that people do wish to donate money, then they should contact appropriate environmental charities or institutions, for example; Australian Marine Conservation Society, The University of Queensland, Griffith University, Queensland University of Technology, James Cook University or the Queensland Conservation Council.

These entities are actively involved in research and programmes that directly benefit wildlife in our Queensland environment.

Dug has some interesting information about his family compiled by: -

The Great Barrier Reef Marine Park Authority

and James Cook University.

Facts about Dugongs

Species: Dugong Dugon

Order: Sirenia

Genus: Dugong

Dugongs, or sea cows as they are sometimes called, are marine animals which can grow to about three metres in length and weigh as much as 400 kilograms. They are the only marine mammals in Australia that live mainly on plants. The name sea cow refers to the fact that they graze on the seagrasses, which form meadows in sheltered coastal waters. As dugongs feed, whole plants are uprooted and a telltale-feeding trail is left. Dugongs are more closely related to elephants than to marine mammals such as whales and dolphins, but their closest living aquatic relatives are the manatees.

Manatees are aquatic mammals that live in freshwater rivers and coastal waters of West Africa, the Caribbean, South America and the southern United States (Florida). Another close relative was Steller’s sea cow, previously found in the northern Pacific. It was hunted to extinction in the 1700s by sealers for its meat. It grew almost three times as long as the dugong and fed on large algae (kelp).

Distribution

Dugongs inhabit shallow, tropical waters throughout the Indo-Pacific region. Most of the world’s population of dugongs is now found in northern Australian waters between Shark Bay in Western Australia and Moreton Bay in Queensland.

Life in the sea

Dugongs swim using their whale-like fluked tail and they use their front flippers for balance and turning. Their movements are often slow and graceful. Early explorers and sailors believed that they were mermaids because of their streamlined bodies and the large teats at the base of their flippers. They have a rounded head with small eyes and a large snout. The nostrils are at the top of the snout and, like mammals, dugongs must surface to breathe.

However, unlike other aquatic mammals such as some whales, dolphins and porpoises, dugongs cannot hold their breath under water for very long. It is generally for only a few minutes,

especially if they are swimming fast.

Dugongs have poor eyesight but acute hearing. They find and grasp seagrass with the aid of coarse, sensitive bristles, which cover the upper lip of their large and fleshy snout. Small tusks can be seen in adult males and some old females. During the mating season, male dugongs use their tusks to fight each other.

Physical Data

Maximum longevity (most die at a younger age)~70 years

Pre-reproductive period (females) 6-17 years

Pre-reproductive period (males) 4-16 years

Gestation period 13-15 months

Litter size 1

Lactation length 14-18 months

Calving interval 3-7 years

Maximum possible rate of increase ~ 5% per year

(e.g. low natural mortality & no human-induced mortality)

Estimated natural mortality rate ~ 5% per year

The slow breeding rate and long life span mean that dugongs are particularly susceptible to factors that threaten their survival. Throughout their worldwide range they are threatened by human impacts, particularly on their habitat.