Snubfin dolphin

Snubfin Dolphin Illustration by E. Hawkins

Scientific name: Orcaella heinsohni

Formally known as Irrawaddy dolphin the Australian snubfin dolphins were recognized as a genetically separate species in 2005.

DISTINGUISHING FEATURES

  •  Snubfin dolphins grow up to 2.7m and weigh 133kg. Males are typically larger than females that reach 2.3m in length and weigh 114kg.
  • Snubfin dolphins are characterised by a round head, no beak or rostrum, small dorsal fin and broad, paddle-like pectoral fins.
  • Snubfin dolphins have a three-tone colouration. They are dark brown along the dorsal cape and light brown on the sides with a white underbelly.
  • Snubfin dolphins have conical teeth, usually less than 20 in each row.

 REPRODUCTION & BREEDING

  •  There remains little known about this species with much of its reproductive biology including the age of maturity and longevity unknown.
  • Breeding and birthing occurs all year round.

DISTRIBUTION & HABITAT

  •  Inhabits near-shore tropical waters from Broome in Western Australia to the Fitzroy River Queensland and parts of Papua New Guinea.
  • Primarily found in shallow waters close to the coast, often near river mouths. Populations tend to be resident with individuals occupying relatively small home ranges.

DIET

  • Snubfin dolphins are generalist feeders with a diet that primarily consists of fish, squid, cuttlefish, octopus and shrimp.

SNUBFIN DOLPHIN SOCIETIES

  • Snubfin dolphins are generally found in small populations of less than 100 individuals.
  • Typical group sizes consist of less than 15 individuals.
  • Snubfins are generally shy towards boats, have low surface profiles and are generally unpredictable. They are highly social among themselves and often seen in mixed species groups with Australian humpback dolphins.
  • A unique behaviour exhibited by snubfin dolphins is the spitting of water. The purpose of this behaviour remains a mystery with some theorising that it is used as a hunting tactic.

COMMUNICATION

  • Snubfin dolphins produce a variety of sounds described as broadband clicks, pulses and whistles. Clicks and pulses can sound similar to creaking and buzzing when the dolphins are foraging for prey. Whistles are thought to be used to communicate between individuals and are more commonly produced during social behaviours.

THREATS

  • Snubfin dolphins are protected in Australian waters, however, their future remains uncertain. Some populations have heavy contaminant loads as a result of pollution from land run-off and coastal development.
  • In Australia, pollution from marine debris, litter, run-off, noise, habitat degradation, interactions with fisheries, overfishing, climate change, coastal development and vessel activities threaten the survival of snubfin dolphins.