Species: Sousa sahulensis
Bundjalung name: Unknown
Status (IUCN): Near threatened

Characteristics

• Length/size: Adults can reach up to 2.75 meters in length and weigh 260kg. Newborn calves are around 1m in length and weigh 14kg.

• Colour: Distinguished by pale grey colouration, long slender beak and low triangular dorsal fin. Adults can acquire white-pink scars that increase with age and speckling on the dorsal fin.

• Breeding/reproduction: Gestation period of 10-12 months. Calves are highly dependent on their mothers for the first few years of life. It is thought that humpback dolphins reach maturity between 10-12yrs. Females give birth to a single calf approximately every 2-4 years. Humpback dolphins can live for over 40 years.

• Diet: Humpback dolphins are carnivorous and feed on a variety of fish, squid and rays.

Habitat: Humpback dolphins live close to the coast within the tropical waters of Australia and Papua New Guinea. They typically are found in small groups near estuaries, deep channels, rocky reefs, in sheltered bays, open ocean and occasionally in surf zones.

Societies: Typically found in small populations (~100) within their range and in small groups of around 4-5 individuals. They are very social animals and live in complex fission-fusion societies where the composition of groups can change over time. Humpback dolphins live in sexually-segregated societies with males forming small strongly-bonded paired-alliances and females having larger networks of associates. Some individuals will display preferences for certain areas and have year-round residence.

Communication: Dolphins produce a diverse range of sounds that include echolocation or sonar clicks, whistles, and burst pulse sounds such as ‘squawks’ and ‘squeaks’. Whistles are used to maintain contact, identify, and to locate other dolphins. Clicks are used for echolocation, assisting in navigation and feeding.

Threats: Marine mammals such as dolphins are protected in Australian waters, however, their future remains uncertain. The largest threats to dolphins in Australia are human pollution, habitat degradation and climate change. Many dolphin deaths in coastal waters have been attributed to ingestion of litter, boat strikes and pollutants such as insecticides. n other areas of the world, tuna fishing, gill netting and drift netting industries in addition to dolphin fisheries contribute to a large number of dolphin deaths each year.

Learn more with the Australian humpback dolphin fact sheet.