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, an extremely knowledgeable ranger, 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 is 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; we saw some of these newly weaned pups.
About
a
quarter of the females 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).
