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Dusky Dolphin

 

Doing it Dusky!

 

 

All dolphin are a delight to behold, but this one more than most.

Dusky dolphin are one of the most acrobatic of all of the dolphin species.  These two metre long speedsters are often easy to spot from a distance, as their leaps and jumps can propel them more than six metres in the air as they cavort together at the ocean’s surface.

All dolphins are of course mammals.  This means that they:

  • Have a vertebrae (or backbone)
  • Feed their young on milk
  • Have some form of hair, fur, or bristles
  • Have warm blood

All dolphin and whales belong to the mammalian order of Cetacea.  This order is broken up into two sub-orders: Mysticeti (baleen whales such as the humpback), and Odontoceti (toothed whales such as the sperm whale and all of the dolphins and porpoises).  Dusky dolphins are part of the family Delphinidae, which include all of the dolphins, and many larger creatures that we term as whales.  Pilot whales, false killer whales, and even orca themselves are all really large dolphins and are a part of the same family as the dusky dolphin.

All dolphin have a beak-like snout, and conical teeth which are used for grabbing and holding their prey.  Once caught they generally swallow their prey whole.  Whilst the beak on the dusky dolphin is smaller than and not as pronounced as its bottlenose cousins, it is still there.  Porpoises differ from dolphin in that they do not have a beak at all, and their teeth are spade-shaped.  This gives them the option of cutting as they bite, so they could far easier bite a chunk out of their prey rather than just grabbing it.  In Australian waters the only porpoise that we have is the spectacled porpoise which lives in sub-Antarctic waters and doesn’t to my knowledge approach the mainland.  This is a creature you might see in places such as Maquarie Island or Heard Island. 

Dusky dolphin tend to like deep offshore water, hunting in pods which can sometimes number less than 20, but often more than 100.  Pods of several hundred individuals are not uncommon, and when this occurs they are brilliant to watch, as at least twenty to thirty individuals will be airborne at any given instance! 

They can be found in the southern hemisphere in temperate and sub-Antarctic waters.  Kiakoura in New Zealand is the place best known for these marine mammals, as they are there in numbers all year.  Kiakoura is a well known area for a diverse range of marine mammals as a cold north-bound current collides here with a warm south-bound one, causing an explosion of planktonic life and the subsequent attraction of the whole food chain around this is stunning.  Deep water is also found just a kilometre off shore here, making it a perfect place to observe deepwater mammals such as these.  In Australia these dolphin have been seen in places such as southern NSW, the eastern edge of Bass Strait, Wilson’s Promontory and Cape Shank (suggesting they move through Bass Strait at times), Kangaroo Island, and Tasmania, but nowhere with any consistency.  Though if there were more boats going out into the deeper water off the continental shelf, sightings of these mammals would undoubtedly improve. 

They are definitely a dolphin to watch out for!

 

 

 

Useful Stuff!

 

Classifying Creatures: 

All living creatures, plants and animals, are given a scientific name which not only can tell you things about that creature, but which makes it separate and identifiable from any other living entity. 

All living things are given seven names (usually in Latin), representing the seven categories of Kingdom, Phylum, Class, Order, Family, Genus and Species.  Kingdom is the most general category, descending in order to Species which is the most specific.  Normally the creature is known scientifically by the last two categories, Genus and Species.  Thus the scientific name for the Dusky Dolphin would be Lagenorhynchus obscurus.  However the full scientific name for the duskies would be:

 

Kingdom          Animalia                       (All animals)

Phylum             Chordata                      (Those with a backbone)

Class                Mammalia                    (See in the article!)

Order               Cetacea                        (Whales Dolphin and Porpoises)

Family              Delphinidae                  (Dolphin)

Genus               Lagenorhynchus            (Group with a small beak, includes hourglass dolphin)

Species            obscurus                       (Dusky Dolphin)

 

 

Sometimes these groups have another placed between them to give more clarity to the definitions.  For instance, these dolphin have the sub-order Odontoceti, which would be placed between the Order and Family names.  Sometimes the final name can go to eight or nine places!

 

 

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