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Explore Three Capes this August

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Tasmania's award-winning Three Capes Track has been a runaway hit with walkers, with more than 28,000 local, national and international visitors completing it since it opened in December 2015.More

Flags fly at Mount Nelson once again

26/06/2018

Tasmania's first signal station has been restored more than 200 years since it began operation on Mount Nelson.
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Southwest ecological burns important for orange-bellied parrot conservation

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Rissos Dolphin

Drawing by Graham Sanders
Risso’s Dolphins are robust dolphins with a blunt head, lacking a distinct beak. The forehead has a distinctive deep crease. The mouthline slopes upward and contain about seven pairs of teeth. The flippers are long, pointed and recurved and the dorsal fin is tall and sickle-shaped. Newborns are light grey and adults are a very light grey to white with a narrow cape on some individuals. The ventrum is dark with a large white anchor shaped grey patch. They often heavily scarred. Both sexes reach up to 230kg in weight. They are very gregarious swimming in groups of 25 up to several hundred and often swim in a line formation although single animals can be found swimming alone at times.

General Information

Risso’s Dolphins are abundant in tropical and temperate waters. They are still hunted off Japan. They generally occur in waters deeper than 1km . They are regularly seen with other cetaceans particularly pilot whales and they have been known to interbreed with Bottlenosed Dolphins. Calving is generally in summer although a newborn was recorded from Victoria in winter. Birth weight is around 60kg and 1.5m. Weaning occurs around 2m in length and maturity at about 3m length. They breed at two or three yearly intervals. They feed mainly on squid.

Stranding Information

Risso’s Dolphins have been recorded as stranding from all Australian States including one from Tasmania. All Australian records of strandings are single individuals although mass strandings have occurred in other parts of the world.