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