Little information is known regarding the Australian snubfin dolphin, as observations of this species are rare. Scientific research has pointed out that the Australian snubfin dolphin is closely related to the Irrawaddy dolphin. In fact, until recent years, it was believed that the Australian snubfin dolphin was a different colored version of the Irrawaddy dolphin.
As their name suggests, the Australian snubfin dolphin can be found swimming in the Northern Australian waters. The Australian snubfin dolphin makes up one of over 40 different dolphin species.
Physical Characteristics and Appearance
These marine mammals are noted for their similar physical appearance to the Irrawaddy dolphin. However, some characteristics differ between the two species. The Australian snubfin dolphin has a brownish to gray colored back that gets lighter along the sides, and the underbody is white, unlike the Irrawaddy dolphin, which is a deeper grayish skin tone.
These dolphins possess a rounded head that’s blunt around the mouth area and lack a beak, and they have a pair of snubbed fins along the sides of their body, hence the name. The dorsal fin is small, tapered back, and located further down the back than other dolphin species. They also have a pair of round dark gray to black eyes, and the blowhole is positioned on top of the head directly above the dolphin’s eyes.
Regarding their body length and weight, the average size for the Australian snubfin dolphin is around 7 – 9 ft. long, with females typically growing slightly larger than their male counterparts, and the average weight for these marine mammals is between 200 – 400 lbs. Because the Australian snubfin dolphin is a marine mammal, it is warm-blooded, breathes air, gives birth to live young, and produces milk to feed its babies.
Diet and Hunting Methods
The primary diet of the Australian snubfin dolphin consists of various fish and cephalopods. They have also been observed bottom-feeding when searching for food. As with other dolphin species, these dolphins’ echolocation can be used to navigate the ocean at night and search for potential prey.
Habitat and Migration
The Australian snubfin dolphin is found exclusively in Australia, primarily in Northern Australian waters. These dolphins inhabit waters off the northern coast within Australia, minimizing their offshore range.
Social Structure and Communication
Not much is known about the social structure of these dolphins, as observations are too rare to come to any conclusions. However, they are believed to be naturally rare species. These dolphins have been observed traveling in pods of 6 or fewer dolphins. However, rare encounters of 12 or more have also been observed.
Communication among the dolphin species consists of various high-pitched clicks and whistles that allow dolphins to communicate with one another, alert others of predators, search for a potential mating partner, inform their pod of food sources, and communicate several other important things to other pod members and local dolphins.
Mating, Reproduction and Lifespan
The average gestation period for these dolphins is believed to be between 12 – 14 months. Newborns are most likely fed milk and nursed until they can hunt and fend for themselves. Sexual maturity begins between the ages of 4 and 8 years, when these dolphins may begin mating and bearing offspring of their own. From the limited information gathered, it is assumed that the Australian snubfin dolphin has a lifespan of around 30 years.
Threats and Predators
The Australian snubfin dolphin faces several threats that are primarily humans based. However, physical scarring suggests that they may also face occasional threats from sharks. Below is a list of the most common threats Australian snubfin dolphins are likely to face:
- Over-fishing
- Waste/chemical Pollution
- Bycatch
- Boat strikes
- Habitat degradation
- Noise Pollution
- Direct kill
- Sharks
Over-fishing– The Australian snubfin dolphin may face threats from over-fishing, which can cause these marine mammals to face issues with depleting food supplies due to human competition. Lowered available food resources would require these marine mammals to migrate away or potentially deal with increased competition for food resources.
Waste/chemical pollution – Waste and chemicals from commercialized areas and agricultural runoffs may interfere with the habitat of the Australian snubfin dolphin. Increased pollution could diminish food stocks, disease, and/or other health/reproductive complications.
Bycatch – In commercial fishing areas, snubfin dolphins have been known to accidentally swim into fishing nets and shark nets while looking for food and, as a result, end up drowning due to their inability to resurface for air. Because dolphins are marine mammals, they cannot survive underwater for very long and must frequent the surface to take in fresh air before holding their breath for another dive.
Boat strikes – Boat strikes are another potential cause of injury or death among the Australian snubfin dolphin. As medium to large boats passes by, they risk striking a dolphin as they travel. This is likely more frequent in highly commercialized areas and inhibited with larger numbers of snubfin dolphins.
Habitat degradation – The construction of marinas, recreational areas, and resource extraction facilities/machinery can all create negative ecological impacts on the habitat of these marine mammals.
Noise pollution – Some researchers believe that noise pollution is becoming a growing concern in areas populated by marine mammals. Noise pollution can interfere with echolocation and a marine mammal’s ability to identify natural sounds in the ocean. It is even believed that loud human-made noises may create lesions and other forms of tissue damage to the brain and ears.
The more commercialized the area, the more opportunities for noise pollution to occur.
Direct kill – While not well recorded, these marine mammals may be purposely killed by hunters/poachers. However, the cause for this is unknown.
Sharks – Lastly, the Australian snubfin dolphin may be attacked by sharks such as the bull shark and tiger shark. The success of these attacks is unknown. However, there has been scarring observed on the bodies of these marine mammals that have been made by predatory sharks, which suggests that these attacks may occur from time to time.
Due to their rare status, these dolphins have been given a high conservation priority status.