Leopard Seal
A bit about them:
A seal, a hunter, a bloody big sea creature!
Dive into the Icy world of the Antarctic and 'sea' how these beautiful monsters go about their day.
Common Name:
Leopard seal or Sea Leopard
Scientific name:
Hydrurga Leptonyx
(Thin-clawed Water worker)
Closely related to/Family tree:
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Order:
Carnivora
Family:
Phocidae
Genus:
Hydrurga
Species:
Leptonyx
The Weddell Seal
The Crabeater Seal
The Leopard Seal.
Their lobed teeth (Hence the name Lobodontini) when shut together allow all members of this tribe to filter krill from water.
All species from this tribe are thought of as Least Concern.
Appearance:
Leopard seals are
aptly named for their spotted patterning along their coat.
Some would say this is because they are reminiscent of a Leopard, and that fact that they are seals.
With long sleek bodies, a Leopard Seal can grow to just shy of 4m long.
Females
are generally larger than males, weighing in at a maximum 590Kg while the males
rarely get above 300Kg.
This makes them the third largest seal species,
Elephant seals and Walruses are their only competitors.
As true seals, they don't have any external ears, but rather 'ear holes' that work much in the same way.
Underwater, they are thought to use their 'ear holes' and whiskers in
combination to detect and locate sound sources from both long and short distances.
A group is called:
A group of seals goes by many names, so take your pick:
Harem
Rookery
Bob
Herd
Pod
Status:
Range:
Leopard seals rarely
stray from their icy home of the South Pole, however they can sometimes be seen
around the South East coast of Australia and as a record breaking sighting, as
far North as Heron Island which is in the bottom end of the Great Barrier Reef!
Seeing one out of this range is extremely rare, but possible.
Habitat:
Inhabiting the icy world of the Antarctic South Pole, these seals are not disturbed by a cold environment as their thick layer of blubber keeps them warm and toasty all year long, in and out of the water.
The blue and white glassy ice floes and drift
ice are their favoured habitat.
Unlike most Antarctic mammals who prefer
"fast ice" (Ice fastened to something more solid and fixed), Sea
Leopards prefer less permanent patches of ice to live and raise their young on.
Hunting for food just below the ice or in shallow waters where they can ambush prey from the shadows.
History:
The history of Leopard Seals isn't long in relation to humans, but it is rich.
To reinforce this, I'm going to start with the death of a 28 year old Marine Biologist, Kirsty Brown, who died at the hands, or mouth rather, of a Leopard Seal in 2003.
Her colleague and the search boat that was now in the water to rescue her spotted her body 10 minutes after the attack, floating about 1km away from where she was attacked.
After trying to resuscitate her for an hour, she was declared to have drowned.
This is the only recorded human death by a Leopard seal, but not the only attack.
So, knowing
how dangerous these animals can be, enjoy this much lighter hearted story of a
photographer who seemingly was babied by a leopard seal.
They have also been known to be interested in and attack the inflatable pontoons of small tour boats in their environment, leading to many being reinforced, less one pops the boat.
Feeding style:
Leopard seals are
hunters, and ambush ones at that.
They will often wait concealed beneath the
ice for penguins or seals to jump in the water, swimming out and snatching up
the unsuspecting prey.
Of course, they don't have hands, and de-feathering a
penguin without hands can be challenging, but Leopard seals manage, very
effectively, to do this by simply biting down and swinging the penguin back and
forth in wide arcs through the air.
Each collision with the water surface helps
to break down their meal into polite, bite sized pieces.
Even without
ambushing tactics, these Seals are strong hunters.
The lack of external ears in
addition to their oddly large pectoral flippers allows the Leopard seal to fly
through the cool Antarctic waters at up to 40kmh. Compare this to the speed of
the fastest Penguin species (Gentoo Penguins), 10kmh, and you could see why
these guys are such successful hunters.
This speed in the water trades off
their mobility on land or ice floes where at best they can muster an awkward
shuffle.
Other than penguins, Leopard seals will also eat squid, fish and even other seal species.
They like
to hunt in shallow waters and will not often dive very deep to find food.
If,
despite all these food options, the Leopard Seal doesn't know what to eat, they
can sieve Krill through their teeth.
Krill is an abundant food source in the
Antarctic and makes up 45% of a Sea Leopards diet.
Leopard Seal teeth are curved and jagged so that when they close together, there are small gaps for water to be forced out, but not much else. So any krill that happened to be closed inside will be separated from the water and downed as an easy snack.
(The image above shows Crabeater Seal teeth, but shows very clearly the complexity of their sieve teeth which are very similar to Leopard Seal teeth)
Predators:
For what I believe to be the first time on this blog, Humans are not only not the biggest threat to this animal, but they aren't even a threat.
Their speed and agility in the water, coupled with their size and intimidating appearance makes them very rarely at the mercy of other animals.
Nesting/mating:
Leopard Seal pregnancies take around 8 months before a single Leopard Seal pup is born. From the time of insemination, the females can delay the implantation of the egg by 3 months to ensure her "little" pup (Sea Leopard Pups can be born in excess of 30kg!) will be born in favourable times and conditions. This can take the whole child making process last 11 months!
Once born, the young seal pup will stay in its little ice hole as mum goes off periodically to find food. The pup will survive off mums milk for only a month before being weaned off. The mother will teach her pup to swim and hunt for its own food in this time also.
Female Leopard Seals become sexually mature as early as 3 years old, while the males only mature at around 6 years old. A female will usually only have one offspring per year, and with an average lifespan of around 12 years in the wild, a female could potentially have up to 9 pups in her lifetime.
Despite having minimal predators, the Leopard Seal rarely gets to reach its
maximum age limit of around 26 years in the wild.
This is due to the extreme environment it calls home being relentlessly challenging, even to those who are born to cope with it's struggles.
Cool tricks:
Leopard Seals can only hold their breath for 15 minutes! While that seams amazing compared to humans, the average seal can hold their breath for an hour, or even up to 2 hours!
While Leopard Seals will eat most things that come their way, researchers were shocked when they caught one off the coast of Sydney which had eaten a whole adult Platypus!
While they are often shallow divers, Sea Leopards can dive to around 80m in search for food. To go this deep they have to collapse their lungs and reinflate them again at the surface!
The world's only captive Leopard Seal was held at Taronga zoo in Sydney, Australia for 7 years before having to be euthanised in 2014. He developed a prolonged illness that couldn't be treated and would have been cruel to keep him alive purely for our enjoyment.
Future prospects:
Leopard Seals seem
to be thriving in their icy home, with bountiful food and habitat, their
populations are booming.
As more and more humans visit Antarctica, for study or leisure, their presence
may affect the local populations not only by mere presence, but also from noise
pollution.
The many boats and tools needed to get through the thick ice of the Antarctic create a lot of noise, both above and below the ice.
As we are learning, most marine animals rely on communication underwater by way of sound and with increased human traffic, we essentially are creating a white noise machine which blocks out their most important form of communication.
This could quickly lead to fragmented populations, separation of mother and young and disturb hunting methods.
Sadly, with or without increased human traffic in the Antarctic specifically, there is more and more humans everywhere else.
More and more people who need food and water and shelter, all
of which need space and will travel.
Everyone, contributing to the warming of
our planet, whether knowingly or not, whether contributing tonnes and tonnes of
CO2 or just living a modest life in the 'burbs'.
It all adds up to the
shrinking of a Leopard Seals home.
While yes, they are thriving currently, if
things keep going how they're going, they are likely to be some of the first
species impacted by global warming.
So do your part to live more sustainably, and the future of the Leopard Seal will remain positive!
A huge thanks to the
podcast
' "Ice Coffee" - The history of human activity in Antarctica'
and it's co-host 'Matt McArthur' who has had his share of experiences and
stories with Leopard Seals. He provided me with many of the great photos in this months blog as well as invaluable information.
If you're interested
in the Antarctic and especially if you're interested in knowing about the
history of human activity there, then give "Ice Coffee" a go!
(Click on the name of the podcast above to get there)
References:
https://oceanwide-expeditions.com/blog/danger-beneath-the-water-10-facts-about-leopard-seals
https://en.wikipedia.org/wiki/Leopard_seal
https://www.antarctica.gov.au/about-antarctica/animals/seals/leopard-seals/
https://australian.museum/learn/animals/mammals/leopard-seal/
https://www.nationalgeographic.com/animals/mammals/facts/leopard-seal?loggedin=true
https://www.coolantarctica.com/Antarctica%20fact%20file/wildlife/leopard-seal.php
https://iaato.org/