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Mammals Leopard Seals
Mammals - Leopard Seals
He looked at me with big, puppy dog eyes, approaching to ten feet away in the clear water. His snout was down, which made his round eyes look really appealing, and he skirted around me – unsure of what to make of this strange creature. The look was uncertain, almost shy. He twisted and disappeared round a small berg. A good start, but I couldn’t see the big one. I wanted to make contact with both.
Three feet away at the edge of my vision the water exploded. My head jerked over to see the other seal completely out of the water, blocking out the sun, a full body breach almost on top of me. A gasp and a ‘whoah!’ from the gathered zodiacs. I laughed out loud, perhaps slightly loudly and a little nervously, and put my head underwater to see the seal disappear. When it reappeared, it’s snout, too, was down, the big round eyes curious.
It’s not a good idea to be too sure of yourself around animals this big, this agile and this powerful, but after a hundred or so encounters with Leopard seals from the safety of boats or shorelines I am left with the impression that in general, the way they look at you, the attitude with which they approach, gives you a strong clue as to their attitude – and how the encounter may play out.
Antarctic Peninsula area
We have most of our Leopard seal encounters off the Antarctic Peninsula – the Peninsula, and the Scotia Sea just to the northeast, are where nearly half of the Antarctic's considerable marine life is produced. The green, thick seas feed enormous amounts of Antarctic Krill, which then seems to feed almost everything else. Any seal, but particularly an energetic seal like a Leopard, can only live in particularly rich, productive seas like these, and the dense life of the Antarctic probably supports between half a million and a million Leopard Seals. We see them all season long, but sightings definitely improve into late summer. This coincides with when the penguin chicks are fledging – lots of naïve chicks with no experience, learning to swim by going to sea for the first time.
A Leopard seal 'playing' with a nearly-dead penguin
Popular conception of the Leopard seal is that they arrive to feed on the hapless chicks. While this is certainly true to some extent – we certainly see plenty of dramatic kills, the overall impression I get is that the young Leopard seals we see are rather clumsy at catching penguins, and that the reason they are in the same place at the same time is rather that both are feeding on the same krill swarms that are at their greatest as the summer ends. We often see Leopard seals lying on floes having a 'siesta' in the afternoons – they generally feed at night. They defecate on the floes – and the faeces is almost always pure krill. I'd estimate that only about one in a hundred scats in the northern Antarctic Peninsula area shows any sign of having eaten penguin – even at the times the penguin chicks are fledging. Chatting about this with Jaume Forcada, the British Antarctic Survey biologist who knows Leopard seals as well as anyone, he thinks that even the big monsters spend most of their time eating krill (- the largest natural protein source on earth), just seasonally changing diet when young seals, fur seals or penguins venture into the water for the first time.
A 2.5 metre seal, a decent size for the Antarctic Peninsula in summer
Different seals, different attitudes
So most of 'our' seals in the peninsula area are just not very good at catching penguins. They're also surprisingly shy – compared to expectations, that is. Interacting with Leopard seals in the water is not always what you might expect. We brief our divers that you can expect a seal to appear on any dive, and that you may have to deal with a rather large, rather 'in your face' animal, several times your size. I think these are the most agile and powerful seals, pound-for-pound, in the world. Of all the seals I have encountered, the Leopard seal is also the one that seems to be by far the most intelligent and engaging, too.
However, our media sense of the dramatic does tend to 'over-portray' certain aspects of these seals. We have all seen far too many dramatic photos of the 'tooth flash' – mouth open at the dome port. The tooth flash is a tiny part of Leopard seal behaviour, and seems to me to be as much as a greeting as a threat, a sometimes nervous way of saying 'just letting you know I'm here, I'm strong (so don't mess with me) and I'm interested in seeing what you are – maybe we can play'. The majority of the seals we encounter are young, and interested in us, perhaps a little shy, maybe playful, but rarely threatening. They tend to be youngsters, smaller than Leopard seals seen at other times and places – up to about two metres long, and weighing maybe 200 kilos. Generally they give me the impression of a big, playful puppy dog. The wide eyes stare at you, far more directly than other seals. With the snout held down, they approach with a slightly nervous, unsure air, coming close and then quickly swimming away, lots of sideways and upwards glances.
Typical Antarctic Peninsula seals in the water, youngsters, perhaps a year old, curious but shy
Sometimes we see bolder – which often means bigger – seals. They no longer have the same 'snout down, puppy-dog eyes' behaviour. The look is more direct, and when they surface the nostrils flare with a soft sniff. Again, they approach and then retreat, but they seem to have a more direct ‘greeting’, consisting of a head-on approach and a tiny lunge forward with the snout, more often accompanied by a flash of those amazing teeth. I’ve had this many times from boats – in the water is a totally different level of interaction. Friends and acquaintances who’ve had much more time in the water with these seals say that the best thing to do is just stand your ground to this greeting. Of course it’s never a good idea to be too sure, and the other advice often offered at the same time is that there comes a time to get out of the water. This last season we had one reasonable sized seal who pushed beyond passes, and bumped and mouthed a couple of the divers. The same as sealions often do, but somehow rather scarier. When you watch these seals hunting penguins, it is effortless – they have honed their skills, and their speed and agility puts them on a par with the most evasive, streetwise gentoo.
This beautiful eight foot long adult female was very interactive and direct, both in and out of the water, but never showed the slightest sign of aggression
The last ‘category’ of Leopard seal is the scary monsters. I've only seen a handful of these, and always in the winter or spring, away from the northern Peninsula area. I've seen them off fur seal colonies as the pups are getting bolder and starting to move offshore, and off King Penguin colonies in winter when the penguins are at their weakest. The real monsters are usually females, who grow considerably bigger than the males - anything over two and a half metres takes on a whole new attitude. At about this size they really broaden out. Their jaws get thick and heavy, their forequarters thicken, the crown on their heads widens, and the smile seems to widen. I've seen a couple of seals over three metres long – and they must have been over 500 kilos each. They take on the famous ‘reptilian’ look - something between a velociraptor and a tyrannosaurus. There are no coy sideways or upwards glances and no hint of nervousness - they always look at you head on, and surface with a snort, nostrils flared wide. The only other animal I’ve seen give such a direct and predatory look is a polar bear. These are not seals I would ever choose to get into the water with.
This is the largest Leopard seal I ever saw, a female well over three metres long, in winter at South Georgia. Notice the massive, broad head. A relaxed animal but not one I'd ever consider snorkelling or diving with.
I once had an encounter with a monstrous female in the water – a nine foot female who came out of nowhere in really poor visibility. I only realized she was there when she appeared five feet away with a close pass. It was easily the scariest experience of my life – not a movie kind of scary, the kind where you put on a brave face. This was a very chilling, unambiguous, 'I might die in the next couple of minutes, there's absolutely nothing I can do about it and I want to whimper and cry' kind of fear. The unexpected adrenaline spike left me shaking and hyperventilating, and I found myself swearing a long string of expletives at the huge head staring uncomprehending at me over my fintips. Looking back, she had been curious and not even slightly aggressive.
Predators of the highest order
My fear had not been entirely abstract – the British Antarctic Survey biologist Kirsty Brown was killed without warning by a huge Leopard seal a few years ago. After her death, a report gathered information from divers and other people who had encountered Leopard seals, and a handful of other occurrences of direct attacks had been documented. The report concluded that there was a continuum of behaviour, from curiosity to aggression, that generally progressed as the encounter progressed – although rarely did this end in an attack. Not really surprising behaviour – this goes for any large predator.
Watching a Leopard seal literally shake a penguin out of its skin is a dramatically horrible yet strangely compelling sight. The seal has no slicing teeth, so the only way it can get meat from a penguin is to shake it apart – this is not merely vicious ‘play’. The power of Leopard seals – even for their size, is incredible. I’ve seen Leopard seals see off bull elephant seals, and colleagues have seen them throw around bull fur seals and cooperate to kill elephant seals. Something human-sized is well within their range. But to be fair this also goes for any large marine animal, particularly in the marine environment. Pilot Whales, Bottlenose Dolphins, Sealions and large seals have all 'played with' or 'attacked' divers – if we choose to enter their world there are risks involved. To put it in context, to my awareness a similar-sized predator, the beloved bottlenose dolphin has killed as many people (one) as Leopard seals have, and attacked many more, and sealions, particularly around breeding season, can be far more belligerent and unpredictable than Leopard seals, without having the ‘killer’ reputation.
I’ve often seen divers and snorkelers with Leopard seals inches behind them or off to the side – often the divers unaware that they had company. The seals like to approach unseen – perhaps like any predator, but also to take a closer look at these large, strange, clumsy animals without the pressure of a head-on greeting. The overwhelming impression, though, is of curiosity and playfulness rather than aggression.
This is the feeling I still have now – memories of my last in-water encounter with a couple of seals. My camera struggled to focus amongst the ice crystals thick in the water as the young seal gingerly approached, stretching gently out to my camera's port and my hand with it's whiskers to the camera port. staring at me with those big eyes. The other seal would stay further away, curious but seemingly intimidated by the group of drysuit-clad photographers. The bolder seal would come within a foot or so, then twist and disappear to the edge of visibility, or dive down and hide under the iceberg. Their acrobatics were effortless, beautiful.
A 'hybrid' seal/sealion
Eared seals – the sealions and fur seals – swim by flapping their long, powerful foreflippers. They basically ‘fly’ through the water like birds, or like manta rays. They are fluid and agile, their tiny pelvis and long trailing hind feet simply acting as rudders. True seals, the group which includes the Leopard seal and most of the southern ocean seals, are generally much bulkier, much more solid and slightly inflexible than eared seals. They are slower, less agile and swim with sideways movements of their large rear flippers.
The long foreflippers and powerful pectoral girdle are more like those of a sealion than those of any other true seal.
The Leopard seal is a true seal, but is in many ways more like an eared seal. Like other true seals, it uses sinuous sideways movements of its rear flippers for propulsion – although these feet are bigger, broader and more winglike than most. The real difference, though, is in the forebody. Unlike any other true seal, but like all the eared seals (ie. sealions and fur seals), the Leopard seal has long, powerful, swept back foreflippers, and huge chest musculature and skeleton. These powerful forelimbs are flapped for propulsion as well as for high speed turns. They are the only true seal that uses all four limbs to swim, and are both faster and more agile than any other, at the same time as being bulkier and sleeker than a sealion, and far more powerful in the hindquarters. I could not imagine any other true seal porpoising behind a speeding zodiac, or breaching clear of the water, but I’ve seen Leopard seals do both.
They are by far the most beautiful of all seals in the water, and have a wonderful mix of the curiosity and agility of a sealion and the grace and glide of a true seal. Perhaps it’s the underwater equivalent of the grace of a leopard or a cheetah – the spotted pattern adds to the picture.
An odd breeding season
Late last November, we came across a Leopard seal hauled out on a floe, nursing her pup. The pup was big, over five feet long. It was also rather fluffy and looked rather like you might imagine a stuffed toy Leopard seal to be. Okay, a little bit of Disneyfication doesn't do any harm.......
A month-old pup, weaned longer and later than other Antarctic seals
Any other true seal would have weaned a long time ago – early spring is normal weaning time for most true seals. But then, accepted wisdom doesn't know very much about Leopard Seals. Almost noone ever sees births or any of the weaning process. All we know is that the larger females have a reputation for being rather aggressive and solitary during the breeding season, chasing off each other and the smaller males from their pups.
This mother, though was anything but aggressive – she looked at us with mild curiosity, then dozed with her pup. She was beautiful, sleek, calm. It was the end of November and this big, healthy looking pup was still being fed. Elephant seals and Weddell seals weaned at least a month ago, even the crabeaters had long abandoned their pups.
Presumably the krill swarms are still building up this early, and late weaning fattens the pups to be independent rather bigger and rather later, to coincide with plenty of fat krill. This sets them up to find their krill and their independence, to pack on a few pounds of muscle and learn how to use their agile bodies. They can hone their skills catching the enormous masses of krill through December and January, ready for their seasonal change of diet - to try their luck on the naïve and dopey penguin fledglings that will appear in the water in February. Seems like rather an elegant strategy to give the next generation a good start to me.
Anthropomorphoism in descriptions irritates me. These are not ‘sinister’ animals, but ones whose survival depends on their being curious, investigative and bold. I can’t conceive how these animals view the world, or these strange and clumsy little creatures that invade their sea more and more frequently for periods of a few minutes. What I go away with, though, is that they are intrigued by us, slightly apprehensive, but in the summer time of plenty, they would have no reason to be dangerous. The overall impression was of an effortless elegance and neutrality that our hype and our need for drama do a huge disservice to. They never asked to be the ‘Happy Feet’ or ‘Eight Below’ villains.