The "Australian Sea Lion", Neophoca cinerea, is confined to Australian Waters. Occasional Australian Sea Lions have been found
off New South Wales, Victoria, Tasmania and as far north as Shark Bay in Western Australia, but their normal range is confined to South Australia and southern Western Australia. The total world population of this rare species is about 11,000.
The AustralianSea Lion is vulnerable to land based predators and most of
their resting and breeding areas are on islands. This is now a totally
protected animal, having suffered very badly from hunting in earlier
times. On Kangaroo Island there is a colony of about 700 Australian Sea
Lions. Human visitors are allowed to see this colony under strict
supervision. A single ranger accompanies each group, but the bus driver
acts to help control us. I have been there twice with my family. The
more recent time was Easter Saturday 2009.
On
this visit our tour group was lucky enough to be escorted by Mary, one
of the rangers, as well as Robert our excellent driver from sealink.
Visitors are not allowed to approach closer than ten metres (33 feet)
to the Australian Sea Lions. This is not as simple as it sounds because the Australian Sea Lions do not always keep away from Humans. In fact,
Mary told us that they sometimes go window shopping at the visitor's
centre. While we were there, on our way down the board walk to the beach we saw a baby Australian Sea Lion only a few feet from our path.
Mary
did not have an easy job, controlling a multinational group of about 40
including children, as well as imparting interesting bits of her
extensive knowledge. Despite the able assistance of Robert this was not
an easy task for a lone ranger.
Mary told us that the Australian
Sea Lions spend about three days at sea feeding, and then return to
land for three days. Australian Sea Lions do not sleep in the water. If they did they would be very vulnerable to their enemies which include the Great White Shark and the Killer Whale. Australian Sea Lions dive to considerable depths
at the edge of the continental shelf and very rapidly eat invertebrates
like crabs and lobsters. While feeding on this type of prey, Australian
Sea Lions typically close their eyes and feel for the invertebrates
with their whiskers. Australian Sea Lions also eat fish squid and
possibly the occasional penguin.
Mating occurs about a week
after the pup is born. The embryo then rests for three months before
starting to grow. This resting period is called an embryonic diapause.
The embryo grows for another 15 months before birth, so the single pups
are born 18 months apart. The pup is weaned at seventeen and a half
months. The pup will continue calling its mother for sometime
afterwards and we saw some of these newly weaned pups.
About a
quarter of the female do not have another baby straightaway, and these
may continue feeding their pups until they are 23 months old.
On
land the Australian Sea Lions rest. In warm weather they will be on the
beach, but if the weather is cold they will climb up into the sand
dunes. At Seal Bay, Australian Sea Lion numbers are very closely
monitored, and the results compared with another colony that does not
get human visitors. No evidence has been found of any harm being done
by the carefully supervised visitors.
When sealing was allowed, the Australian Sea Lions were killed by the tens of thousands,
basically just so they could be boiled down for their oil. Unlike
seals, Australian Sea Lions do not have a very valuable coat, having
much coarser hair.
Australian Sea Lions have been protected by
Western Australian Law since 1892, by South Australian Law since 1964,
and by Australian federal law since 1975. Despite this legal protection
their numbers do not seem to be increasing, and may be declining.
Australian Sea Lions sometimes get entangled in fishing nets and other
things like Cray fishing equipment. If they are unable to reach the
surface they will drown.
There has also been concern about fish
farms being started close to the areas used by Australian Sea Lions.
Although Australian Sea Lions are totally protected be both federal and
state law, there is little doubt that some are still shot illegally.
Australian
Sea Lions will live for up to 25 years. The females become sexually
mature at about 5 years old and the males at about 8. Males can weigh
up to about 640 pounds (300 Kg) and the females up to about 220 pounds
(100 Kg). On land they look a little ungainly, but they can apparently
move as fast as a Human over the sand. A new born pup weighs about 15
pounds (7 Kg).