A Weaner's World
March 15, 2012
A young Northern elephant seal’s life is difficult from the start. At the very moment a pup emerges from the comfort of the mother’s womb, it is greeted by a harsh and violent world. Other mothers may threaten the newborn, often with their teeth, if it wanders or wobbles too close. A neighboring cow might even attack a pup as it is being born.
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| A neighbor cow bites a newborn |
This defensive strategy may protect a cow’s precious milk from being stolen by other wayward pups. Despite being fiercely protected by its own mom, the new pup can hardly escape the males that barrel through the colony in order to chase off intruders or mount the cows in a show of dominance. Often, the new weak pup can be crushed by a two-ton male that it didn’t even see coming.
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| MC Hammer with large pup that he had just killed |
Sometimes, a pup will become separated from its mother during a scuffle between cows or adult males. It’ll wander around, desperately calling to its mom while other cows snap at it with their sharp teeth. Occasionally, the mother will find the pup and they will be happily reunited. At other times, a lost pup’s mother will abandon it altogether for a variety of different reasons. Because other nursing cows will viciously chase the pup away, it will often end up starving to death. Sometimes the abandoned pup may die faster from wounds inflicted by aggressive adults since it has no mother to protect it. The luckier pups will nurse from their mothers for an average of 28 days before they are weaned and are left alone on the beach. We affectionately call them “weaners.”
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| Mothers squabble over pups and territory |
On rare occasions, however, an abandoned pup might find a surrogate mom who will let it nurse along with her own baby. Despite finding a source of life-giving milk, the adopted pup will have to fight really hard for its share, since the cow’s biological offspring will often be bigger, healthier, and greedier. Sometimes the adopted pup will gain enough weight to make it to weaning, although it often will be smaller than his adoptive sibling. We saw one such case on the island this year, when a tiny female pup abandoned several days after birth found a replacement mother, Lodi, to nurse her. This feisty little creature, was nicknamed “Little 26” (after the number that Lodi and her own pup were bleached with to keep track of them), and she completely won our hearts.
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| Little 26 (left) nursing along with her adoptive brother |
She was still tiny when Lodi finally left, about half the size of her adoptive brother, “Big 26.” Nevertheless, the tiny weanling found a group of other weaner friends to play with and snuggle up to in order to stay warm. Like the other weaners, she molted her black fuzzy lanugo (natal pup fur) to reveal a silvery weaner coat. She moved all around Sand Flat and had an immense amount of energy despite being so thin that she was basically skin and bones.
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| Little 26 (right) with friends |
Deep down we all knew that she wouldn’t make it without the blubber reserves that weaners use to provide nourishment and hydration while they learn how to swim and forage in the sea. A few days ago, Little 26 fell into a gulch and was washed away by swells. Whether she’ll swim to safety somewhere and learn to eat fish quickly enough to survive (which is highly unlikely), we’ll never know. But it is so unusual and amazing that an abandoned pup could find a cow that would let it steal milk, and then survive for so long afterwards.
Luckier pups with more experienced mothers will nurse continuously until they grow from their birth weight of 60-80 lbs to a weaning weight of 200-300 lbs. Protected by their knowledgeable mother, they will spend all of their time eating and sleeping, comforted with their warm mothers by their side. They’ll sleep for hours at a time, undergoing sleep apnea during which they won’t breathe for many minutes in order to save energy and prevent precious water evaporation by breathing. They’ll build up the vital blubber layer that will give them valuable nutrition in the several months they will have to fast before their first trip to sea.
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| Pup with protective mother |
Their idyllic life will end abruptly when their mother is impregnanted by the alpha male of the colony and departs for her own long journey in the sea to replenish her lost resources. Without the food and protection of its mother, the new weaner will have to face a harsh and difficult world. First of all, the huge amount of accumulated blubber makes it difficult for it to move around on land. It makes it a challenge getting out of the way of fighting males, and often times new weaners are brutally attacked by adult males due to displaced aggression or simply for getting in the way.
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| Weaner with gashes from an adult male attack (foreground) |
We witnessed one such incident in Mirounga Beach when MC Hammer put a few very deep gashes in the neck of Grasshopper’s male weaner as soon as his mother left the beach. While scrambling to leave the dangerous Mirounga Beach territory, Grasshoper’s weaner fell several feet into Log Channel, a narrow gulch in which animals can often become trapped until higher tides and swells can help wash them back up onto safer land. The injured weaner spent several days bleeding and shivering in Log Channel, occasionally getting carried out toward the perilous sea by the strong waves. Surprisingly, he managed to ride one of the waves back out of Log Channel onto the safety of the Isthmus one morning. Although he was safer on land, now he had to face the aggressive gulls who incessantly pecked at the infected flesh of his neck wounds.
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| Grasshopper’s weaner with neck injuries |
Sometimes the gulls can wear down an injured pup in this way, and we have often seen gull attacks precede a pup’s untimely death. Surprisingly, Grasshopper’s weaner managed to hold on. He recovered with time and his wounds are now healed to the point of being nothing but battle scars. For now, he looks healthy and active, and spends most of his time playing with other weaners. He has even returned to Mirounga Beach and began to venture into the shallow waters by his birthplace.
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| Healed Grasshopper (front row, third from left) with friends |
Some weaners get really, really lucky. Unwilling to accept their fate as an independent young seal with no constant source of milk, they persistently seek another source of nourishment. Sometimes, such pushy youngsters will have the good luck to find a cow that had recently lost her own pup and is willing to adopt another. Such weaners revert back to puphood and can sometimes nurse for up to 4 more weeks from their surrogate mother, growing up to twice as large as their normal cohorts – up to 600 pounds! However, being a superweaner is not necessarily an advantage. Their large size impedes their movement on the beach, making it difficult to evade aggressive males and necessitating a longer fasting period on land before they are svelte enough to enter the sea. Last year, we witnessed MC Hammer gravely injure that season’s sole superweaner, causing her to die from horrific head wounds. This year’s superweaner had a much happier fate. He was one of our first weaned pups, born to an older cow named Kyra. He found a second mother in Ivy, a cow that was separated from her own pup early in its life. Although Ivy often seemed irritated with Superweaner’s persistent urgings for more milk, he eventually won her over and she ended up letting him nurse for 13 days!
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| Superweaner with Ivy |
Although he was bigger than most of the other weanlings, he did not grow to the gargantuan proportions that we saw in last year’s superweaner, which is probably a good thing since he’s been able to move around well enough to avoid danger. Right now, we can hardly tell him apart from the other weaners. Perhaps this little extra nutritional boost was all he needed for a good start in life.
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| Superweaner (left) with normal weaner |
So what is life like for all of the other weaners? Well, it involves plenty of sleeping during the first few weeks in order to save energy and ration those precious fat reserves. They huddle in little groups called ‘weaner pods’ for protection while the adult seals are still around in the colony.
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| Sleepy weaners |
Once they start losing weight, the weaners become more active and start exploring their surroundings, learning how to swim, interact with each other, and all of those other vital skills that they need to survive in the sea. They learn these skills by playing in puddles, submerging their noses in muddy water and bl
owing bubbles, rooting around for rocks and washed-up jellyfish, picking them up and trying to chew on them.
owing bubbles, rooting around for rocks and washed-up jellyfish, picking them up and trying to chew on them.
They learn that rocks and sand and plants are not edible, and they learn how not to swallow water or get it up their nose.
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| Chewing rocks |
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| Blowing bubbles |
They learn to fight by playing with each other in little groups, lightly biting their friends’ necks, hind ends, flippers, or any other body parts that look fun to chew.
They vocalize at each other and learn aggressive social cues from weaners that don’t seem to want company. They discover what lies behind them by tilting their heads back and rearing up as high as they possibly can by using their impressive abdominal muscles. They find out that they have hindflippers by leaning back and biting on them. These seemingly ridiculous activities build necessary skills that help them fully assess their surroundings and understanding sensations in their hind body that might mean danger from attacking predators.
After all of this time building up their strength on land, the weaners are finally drawn to the sea. Northern elephant seals are truly pelagic marine mammals, meaning that they spend the majority of their life in the ocean, traveling further, wider, and deeper than most seals, eating and even sleeping in the water. But the weaners need some training before they can go on their first long trip to sea. They start by venturing into the shallows near their natal beaches. They begin swimming clumsily in protected waters, playing together in the waves, diving down for jellyfish and other objects to play with, and chasing each other under the water.
Eventually, they’ll swim farther out, building up the strength and coordination necessary to navigate rough seas. They’ll chase fish until they learn to catch them in their mouths, although it might take them some time to learn to swallow them whole. They’ll learn to look for gentle sloping beaches where they can haul out to rest, and how to swim with speed and agility to avoid sharks. It’s hard to believe that they’ll be able to accomplish all this when we look at them now, clumsily splashing in the waters.
However, two cases that we’ve seen this year have proven to us that elephant seals can manage to survive even before they’ve completed ‘weaner training.’ One afternoon while looking for marine invertebrates, we found an unknown male pup in the intertidal area below Sand Flat. He seemed rather small, possibly having been separated from his mother by high swells before he was ready to be weaned. We put a tag in his hindflipper and dubbed him “Mystery Weaner,” although we conjectured that he could have come from the small harem across the channel on West End Island.
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| Mystery weaner when we first found him |
After spending several days shivering in tidepools and being bashed by high swells, he disappeared and we considered him gone. Much to our surprise, Mystery Weaner reappeared several days later on Sand Flat and has now fully integrated into the local weaner society. How he managed to survive such rough conditions, swim through the rough seas between Southeast Farallon Island and West End, and then haul out onto Sand Flat – we have no idea. But we do know that he’s doing quite well so far, although he is a little bit smaller than some of his local weaner friends.
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| Mystery weaner (front row, darker animal on the right) playing with a Sand Flat weaner |
One of our Sand Flat pups has had quite an exciting life as a weaner. Refusing to spend his days wallowing in the stinky puddles on Sand Flat with other clueless weaners, he opted instead to climb up to the grassy terrace a
bove Sand Flat and explore quite different surroundings.
bove Sand Flat and explore quite different surroundings.
He wobbled around in the grass for several weeks, at one point making it up almost to the houses. He got some quality, undisturbed sleep in the soft grass, but eventually tired of life alone in the highlands.
After returning to Sand Flat, he disappeared the next day in search of more adventure. Although we started thinking that he didn’t make it in the sea, he reappeared in one of the gulches on the other side of the island 10 days after we last saw him.
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| ‘Miracle weaner’ returns to the gulch |
He proved to us that weaners can indeed swim and survive in the sea fairly soon after being left by their mothers, although he might be a little more precocious than the rest. And while Northern elephant seal weaners spend up to two and a half months on land (on average) before their first big trip to sea, there definitely is individual variation in their behavior.
The mortality rate for weaners in their first year of life is greater than 50%, but those that make it past that point will have a much better chance at survival since that percentage will decrease with age and skill. Many will return to this same island and the same beaches to give birth to their own pups, as we’ve seen with successful breeders such as MC Hammer and Kyra, who were both born and tagged on the Farallons. A difficult life awaits our Farallon weaners, but perhaps we’ll be lucky enough to see some of these amazing animals return here in the winters ahead.