Speaker 1: Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff. Lauren Vogelbaum. Here.
Speaker 1: Each summer, for reasons we humans don't particularly understand, about
Speaker 1: twelve thousand male Pacific walruses pack themselves onto the beaches
Speaker 1: of Round Island, off the southwest coast of Alaska in
Speaker 1: the Bering Sea. That's some nine million pounds worth of
Speaker 1: walrus on a two mile long island. For a metric friends,
Speaker 1: that's around four million kilos on a three kilometer stretch.
Speaker 1: Known as rather gregarious creatures, the walruses may simply enjoy
Speaker 1: one another's company, although they do occasionally jab a neighbor
Speaker 1: with their long tusks to assert dominance. Or perhaps they're
Speaker 1: trying to stay warm in the far below freezing temperatures.
Speaker 1: Whatever they're up to, the female walruses are far away
Speaker 1: in root, back from their yearly migration north, with calves
Speaker 1: in tow. Whatever the reason for this month's long mail bonding,
Speaker 1: it presents an ideal setting for scientists to study the mammal.
Speaker 1: In the years since research began, biologists have learned a
Speaker 1: lot about this hearty creature of the Arctic, whose name
Speaker 1: possibly roots from a sort of funny combination of the
Speaker 1: Dutch words for horse and whale. Walruses are the second
Speaker 1: largest pinniped, which is an order of animals that also
Speaker 1: include seals and sea lions. Only the elephant's seal can
Speaker 1: grow larger. Walruses are also the only member of the
Speaker 1: order to possess tusks, two especially long upper canines that
Speaker 1: can reach lengths of three feet nearly a meter and
Speaker 1: weigh twelve pounds each that's over five kilos. They primarily
Speaker 1: use their tusks as built in tools for managing their
Speaker 1: icy environments. They can hook their tusks into the ice
Speaker 1: to pull themselves out of the water or just take
Speaker 1: a break from swimming, or when underwater, break breathing holes
Speaker 1: in the ice. Both the males and females have tusks,
Speaker 1: but the males are longer, straighter, and stronger, and can
Speaker 1: continue to grow for fifteen years. They do also use
Speaker 1: them for establishing dominance when males get feisty. The especially
Speaker 1: thick skin around their neck and shoulders protects them from
Speaker 1: sharp jabs. Walruses are darkish brown in color and have
Speaker 1: large round bodies. They seem clumsy on land, but after
Speaker 1: all they spend About two thirds of their lives in water,
Speaker 1: where they move easily and can dive down about the
Speaker 1: length of an American football field. Walruses have four flippers
Speaker 1: with rough bottoms to help provide traction on slippery snow
Speaker 1: and ice. In the water, they can reach speeds of
Speaker 1: about twenty miles an hour that's thirty five kilometers an hour.
Speaker 1: There are two subspecies, the Atlantic walrus and the Pacific walrus,
Speaker 1: which are totally isolated from each other. Pacific walruses are
Speaker 1: a little bit bigger. They can top out at twelve
Speaker 1: feet long that's three and a half meters and can
Speaker 1: weigh up to thirty seven hundred pounds that's about seventeen
Speaker 1: hundred kilos. In both subspecies, the males are a bit
Speaker 1: bigger than the females. Walruses are located throughout the Arctic.
Speaker 1: There are a lot more Pacific walruses and estimated two
Speaker 1: hundred and fifty thousand versus only around fifty thousand Atlantic walruses.
Speaker 1: Their populations are considered vulnerable due to previous overhunting and
Speaker 1: now climate change. They are fabulously adapted for their environments.
Speaker 1: Walruses live in one of the harshest environments on Earth,
Speaker 1: temperatures are frigid, and again they spend most of their
Speaker 1: time in the water, where you lose body heat a
Speaker 1: lot faster. They have a thick layer of body fat
Speaker 1: just under their skin that keeps them warm. It streamlines
Speaker 1: their form and provides them with energy when the food
Speaker 1: supply dips low. This blubbery layer can be up to
Speaker 1: four inches thick some ten centimeters and may comprise a
Speaker 1: whole third of the animal's body mass. In the winter,
Speaker 1: the walrus blod vessels also con strict and move blood
Speaker 1: away from skin and towards chief organs, where heat won't escape.
Speaker 1: This is so effective that you can see it. When
Speaker 1: a walrus has been under water for a long time,
Speaker 1: its skin will go from pinkish to white. Their brown
Speaker 1: hair is short and probably doesn't help in the warmth department.
Speaker 1: Their circulation is also what helps them dive for long
Speaker 1: periods without coming up for air. When they dive, their
Speaker 1: heart rate slows and blood travels to the organs that
Speaker 1: need the most oxygen. They also have a high level
Speaker 1: of a protein called myoglobin in their blood. Myoglobin binds
Speaker 1: to oxygen, carries it through the walrus's body and stores
Speaker 1: it in the muscles. Because water doesn't allow for great visibility,
Speaker 1: walruses have adapted other senses. The animal's ears too small
Speaker 1: openings with protective flaps can detect noises up to a
Speaker 1: mile away. That's over a kilometer and a half. Its
Speaker 1: sense of smell can help it detect approaching predator and
Speaker 1: identify its own young. In addition, a walrus has frankly
Speaker 1: adorable whiskers, some four hundred to seven hundred of them
Speaker 1: in thirteen to fifteen rows around the nose. They're attached
Speaker 1: to muscles and supplied with blood and nerves, which makes
Speaker 1: them highly sensitive. They use these whiskers to locate prey.
Speaker 1: They hunt with their noses to the seafloor. They don't
Speaker 1: actually use their tusks to dig for food, as previously thought,
Speaker 1: but rather blow streams of water out of their nostrils
Speaker 1: to stir up burrowing animals. They prefer clams, but will
Speaker 1: eat anything they find, including worms, snails, crabs, and sea cucumbers.
Speaker 1: Some of those animals have shells, and walruses don't chew
Speaker 1: their food, so they can't crack the shells, but they
Speaker 1: have an equally effective method. A walrus can use its
Speaker 1: mouth as a vacuum to suck the animal right out
Speaker 1: of its shell. This section is so powerful that in captivity,
Speaker 1: walruses have sucked wholes and plywood and strict paint from walls.
Speaker 1: Walruses consume some four to six percent of their body
Speaker 1: weight every day, meaning an adult animal might consume six
Speaker 1: thousand clans in one sitting. These animals have few predators
Speaker 1: other than the occasional killer whale or brave polar bear.
Speaker 1: Thus they tend to live relatively long life spans of
Speaker 1: around thirty years. During their lifetimes, male and female walruses
Speaker 1: live apart in separate herds. Females stay with the same
Speaker 1: herd throughout their lives, and males leave their birth herd
Speaker 1: after two or three years to join the male herd.
Speaker 1: As we said at the top, Pacific female herds migrate
Speaker 1: every year. We know less about the Atlantic walrus, but
Speaker 1: they don't seem to migrate in the summer. When the
Speaker 1: ice melts and recedes, the Pacific females head north then
Speaker 1: return south before the ice freezes in the winter. Researchers
Speaker 1: aren't sure why the males don't migrate to the same
Speaker 1: extent that females do might have to do with sperm production.
Speaker 1: The herds meet in the winter. When the females head south,
Speaker 1: they'll congregate on an ice pack and basically be serenaded
Speaker 1: by the males, which inflate pouches near their throat to
Speaker 1: remain upright in the water and vocalize, clacking their teeth,
Speaker 1: whistling and making bell sounds until one of the females
Speaker 1: is impressed enough to come mate. Pregnancy lasts about fifteen months,
Speaker 1: so calves are born in the spring during migration north.
Speaker 1: Mothers are very protective of their young and may form
Speaker 1: a separate nursery herd with other cows. Females stay close
Speaker 1: to their newborns for at least a year and sometimes
Speaker 1: over two years, and may nurse that entire time. Cows
Speaker 1: often give their young rides on their backs, even though
Speaker 1: calves can usually swim after just a month or so.
Speaker 1: Those calves are big bundles of joy. They can weigh
Speaker 1: from one hundred to one hundred and sixty pounds of
Speaker 1: birth that's forty five to seventy five kilos. They tend
Speaker 1: to be darker than the adults in color and get
Speaker 1: lighter as they age. They're very social and seemingly smart creatures.
Speaker 1: Young males have been observed keeping watch over injured walruses
Speaker 1: and pushing dead or dying walruses off of ice floes
Speaker 1: so that nearby hunters can't get to them. Female walruses
Speaker 1: may also carry their dead young away from hunters. Though
Speaker 1: walruses have few natural predators, humans have hunted them for
Speaker 1: thousands of years for their meat, tusks, bones, skin, and oil.
Speaker 1: In the mid to late eighteen hundreds, in particular, walrus oil,
Speaker 1: created by boiling walrus blubber at high temperatures, was sought
Speaker 1: for lamps, soap, and as a machine lubricant. From eighteen
Speaker 1: sixty to eighteen eighty, some ten thousand walruses were killed
Speaker 1: every year in the Eastern Arctic alone. Walrus hunting has
Speaker 1: since been restricted generally only two native populations who have
Speaker 1: traditionally relied on the walrus as a source of food
Speaker 1: and other supplies. In Alaska, for example, peoples like the
Speaker 1: Inupia and the Upic have historically used every part of
Speaker 1: the animal. Stomachs can be made into containers and drums,
Speaker 1: a skins made into boat covers and rope, and ivory
Speaker 1: is used in art. Local management keeps harvests within sustainable limits.
Speaker 1: In the United States, the Marine Mammal Protection Act of
Speaker 1: nineteen seventy two protects the walrus from hunters and prohibits
Speaker 1: the trade of walrus ivory. Only ivory that predates the
Speaker 1: law or has been carved by an Alaska native can
Speaker 1: legally be sold. Other national and international laws protect the
Speaker 1: animals from harvest and restrict global trade of walrus products.
Speaker 1: These measures have stabilized walrus populations, but unfortunately they now
Speaker 1: face another threat, global warming. As Earth's average temperature increases,
Speaker 1: more and more ice in the polar region recedes. This
Speaker 1: could be devastating to walruses because they depend on the
Speaker 1: ice shelves as a resting ground between dives. The shallow
Speaker 1: waters where walruses like to feed now have little or
Speaker 1: no ice for mothers and babies to rest on when feeding.
Speaker 1: As a result, mothers may have to travel farther to
Speaker 1: reach feeding and resting grounds. This means they may become
Speaker 1: separated from their young. Areas that do have ice shelves
Speaker 1: are deeper, and the walruses aren't accustomed to diving that
Speaker 1: deep for food. Only time will tell whether the walrus
Speaker 1: can adapt to the longer commute and deeper dives required
Speaker 1: because of the ICE's retreat. Today's episode is based on
Speaker 1: the article how Walruses work on how stuffworks dot Com,
Speaker 1: written by Jennifer Wharton. Brain Stuff is production by Heart
Speaker 1: Radio in partnership with how Stuffwork dot Com and is
Speaker 1: produced by Tyler Klang. For more podcasts from My heart Radio,
Speaker 1: visit the heart Radio app, Apple Podcasts, or wherevery listen
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