WEBVTT - How Do Walruses Work? 0:00:01.840 --> 0:00:08.800 Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff. Lauren Vogelbaum. Here. 0:00:10.600 --> 0:00:15.440 Each summer, for reasons we humans don't particularly understand, about 0:00:15.480 --> 0:00:19.880 twelve thousand male Pacific walruses pack themselves onto the beaches 0:00:19.920 --> 0:00:22.759 of Round Island, off the southwest coast of Alaska in 0:00:22.840 --> 0:00:26.960 the Bering Sea. That's some nine million pounds worth of 0:00:27.040 --> 0:00:30.600 walrus on a two mile long island. For a metric friends, 0:00:30.600 --> 0:00:33.960 that's around four million kilos on a three kilometer stretch. 0:00:35.200 --> 0:00:39.160 Known as rather gregarious creatures, the walruses may simply enjoy 0:00:39.159 --> 0:00:42.680 one another's company, although they do occasionally jab a neighbor 0:00:42.760 --> 0:00:46.440 with their long tusks to assert dominance. Or perhaps they're 0:00:46.479 --> 0:00:49.440 trying to stay warm in the far below freezing temperatures. 0:00:50.479 --> 0:00:53.640 Whatever they're up to, the female walruses are far away 0:00:54.200 --> 0:00:57.560 in root, back from their yearly migration north, with calves 0:00:57.600 --> 0:01:02.280 in tow. Whatever the reason for this month's long mail bonding, 0:01:02.680 --> 0:01:06.040 it presents an ideal setting for scientists to study the mammal. 0:01:07.200 --> 0:01:10.120 In the years since research began, biologists have learned a 0:01:10.160 --> 0:01:13.440 lot about this hearty creature of the Arctic, whose name 0:01:13.560 --> 0:01:16.360 possibly roots from a sort of funny combination of the 0:01:16.440 --> 0:01:21.520 Dutch words for horse and whale. Walruses are the second 0:01:21.640 --> 0:01:24.680 largest pinniped, which is an order of animals that also 0:01:24.680 --> 0:01:28.440 include seals and sea lions. Only the elephant's seal can 0:01:28.480 --> 0:01:32.440 grow larger. Walruses are also the only member of the 0:01:32.560 --> 0:01:36.959 order to possess tusks, two especially long upper canines that 0:01:37.000 --> 0:01:39.920 can reach lengths of three feet nearly a meter and 0:01:40.000 --> 0:01:44.759 weigh twelve pounds each that's over five kilos. They primarily 0:01:44.880 --> 0:01:48.080 use their tusks as built in tools for managing their 0:01:48.320 --> 0:01:52.040 icy environments. They can hook their tusks into the ice 0:01:52.160 --> 0:01:54.480 to pull themselves out of the water or just take 0:01:54.520 --> 0:01:58.440 a break from swimming, or when underwater, break breathing holes 0:01:58.480 --> 0:02:02.320 in the ice. Both the males and females have tusks, 0:02:02.440 --> 0:02:05.960 but the males are longer, straighter, and stronger, and can 0:02:06.000 --> 0:02:10.040 continue to grow for fifteen years. They do also use 0:02:10.080 --> 0:02:13.800 them for establishing dominance when males get feisty. The especially 0:02:13.840 --> 0:02:16.560 thick skin around their neck and shoulders protects them from 0:02:16.639 --> 0:02:21.120 sharp jabs. Walruses are darkish brown in color and have 0:02:21.360 --> 0:02:26.000 large round bodies. They seem clumsy on land, but after 0:02:26.040 --> 0:02:28.560 all they spend About two thirds of their lives in water, 0:02:28.680 --> 0:02:31.120 where they move easily and can dive down about the 0:02:31.240 --> 0:02:35.480 length of an American football field. Walruses have four flippers 0:02:35.520 --> 0:02:38.640 with rough bottoms to help provide traction on slippery snow 0:02:38.639 --> 0:02:41.560 and ice. In the water, they can reach speeds of 0:02:41.560 --> 0:02:44.920 about twenty miles an hour that's thirty five kilometers an hour. 0:02:46.080 --> 0:02:50.399 There are two subspecies, the Atlantic walrus and the Pacific walrus, 0:02:50.600 --> 0:02:54.600 which are totally isolated from each other. Pacific walruses are 0:02:54.639 --> 0:02:57.079 a little bit bigger. They can top out at twelve 0:02:57.080 --> 0:02:59.520 feet long that's three and a half meters and can 0:02:59.520 --> 0:03:02.360 weigh up to thirty seven hundred pounds that's about seventeen 0:03:02.400 --> 0:03:06.080 hundred kilos. In both subspecies, the males are a bit 0:03:06.120 --> 0:03:10.560 bigger than the females. Walruses are located throughout the Arctic. 0:03:11.200 --> 0:03:14.240 There are a lot more Pacific walruses and estimated two 0:03:14.320 --> 0:03:18.240 hundred and fifty thousand versus only around fifty thousand Atlantic walruses. 0:03:18.919 --> 0:03:22.880 Their populations are considered vulnerable due to previous overhunting and 0:03:23.200 --> 0:03:28.440 now climate change. They are fabulously adapted for their environments. 0:03:29.120 --> 0:03:32.120 Walruses live in one of the harshest environments on Earth, 0:03:33.080 --> 0:03:36.080 temperatures are frigid, and again they spend most of their 0:03:36.160 --> 0:03:38.360 time in the water, where you lose body heat a 0:03:38.400 --> 0:03:42.000 lot faster. They have a thick layer of body fat 0:03:42.120 --> 0:03:45.080 just under their skin that keeps them warm. It streamlines 0:03:45.120 --> 0:03:47.800 their form and provides them with energy when the food 0:03:47.800 --> 0:03:51.840 supply dips low. This blubbery layer can be up to 0:03:51.920 --> 0:03:55.480 four inches thick some ten centimeters and may comprise a 0:03:55.520 --> 0:03:57.880 whole third of the animal's body mass. In the winter, 0:03:59.200 --> 0:04:02.360 the walrus blod vessels also con strict and move blood 0:04:02.360 --> 0:04:06.360 away from skin and towards chief organs, where heat won't escape. 0:04:06.960 --> 0:04:10.000 This is so effective that you can see it. When 0:04:10.000 --> 0:04:12.200 a walrus has been under water for a long time, 0:04:12.480 --> 0:04:16.680 its skin will go from pinkish to white. Their brown 0:04:16.720 --> 0:04:20.080 hair is short and probably doesn't help in the warmth department. 0:04:21.160 --> 0:04:24.039 Their circulation is also what helps them dive for long 0:04:24.120 --> 0:04:27.680 periods without coming up for air. When they dive, their 0:04:27.680 --> 0:04:30.600 heart rate slows and blood travels to the organs that 0:04:30.680 --> 0:04:34.080 need the most oxygen. They also have a high level 0:04:34.080 --> 0:04:38.080 of a protein called myoglobin in their blood. Myoglobin binds 0:04:38.080 --> 0:04:41.159 to oxygen, carries it through the walrus's body and stores 0:04:41.200 --> 0:04:45.880 it in the muscles. Because water doesn't allow for great visibility, 0:04:46.320 --> 0:04:51.159 walruses have adapted other senses. The animal's ears too small 0:04:51.200 --> 0:04:54.240 openings with protective flaps can detect noises up to a 0:04:54.320 --> 0:04:57.760 mile away. That's over a kilometer and a half. Its 0:04:57.760 --> 0:05:00.440 sense of smell can help it detect approaching predator and 0:05:00.520 --> 0:05:05.040 identify its own young. In addition, a walrus has frankly 0:05:05.080 --> 0:05:08.279 adorable whiskers, some four hundred to seven hundred of them 0:05:08.400 --> 0:05:12.479 in thirteen to fifteen rows around the nose. They're attached 0:05:12.480 --> 0:05:15.400 to muscles and supplied with blood and nerves, which makes 0:05:15.440 --> 0:05:19.599 them highly sensitive. They use these whiskers to locate prey. 0:05:20.480 --> 0:05:24.360 They hunt with their noses to the seafloor. They don't 0:05:24.400 --> 0:05:27.839 actually use their tusks to dig for food, as previously thought, 0:05:28.200 --> 0:05:31.200 but rather blow streams of water out of their nostrils 0:05:31.240 --> 0:05:35.360 to stir up burrowing animals. They prefer clams, but will 0:05:35.480 --> 0:05:41.360 eat anything they find, including worms, snails, crabs, and sea cucumbers. 0:05:41.360 --> 0:05:44.599 Some of those animals have shells, and walruses don't chew 0:05:44.640 --> 0:05:47.360 their food, so they can't crack the shells, but they 0:05:47.400 --> 0:05:50.960 have an equally effective method. A walrus can use its 0:05:51.040 --> 0:05:53.880 mouth as a vacuum to suck the animal right out 0:05:53.880 --> 0:05:58.320 of its shell. This section is so powerful that in captivity, 0:05:58.600 --> 0:06:02.960 walruses have sucked wholes and plywood and strict paint from walls. 0:06:04.000 --> 0:06:06.960 Walruses consume some four to six percent of their body 0:06:07.000 --> 0:06:10.760 weight every day, meaning an adult animal might consume six 0:06:10.839 --> 0:06:15.480 thousand clans in one sitting. These animals have few predators 0:06:15.560 --> 0:06:18.680 other than the occasional killer whale or brave polar bear. 0:06:19.680 --> 0:06:22.240 Thus they tend to live relatively long life spans of 0:06:22.279 --> 0:06:27.240 around thirty years. During their lifetimes, male and female walruses 0:06:27.360 --> 0:06:30.960 live apart in separate herds. Females stay with the same 0:06:31.000 --> 0:06:33.800 herd throughout their lives, and males leave their birth herd 0:06:33.839 --> 0:06:36.400 after two or three years to join the male herd. 0:06:37.560 --> 0:06:40.479 As we said at the top, Pacific female herds migrate 0:06:40.560 --> 0:06:44.599 every year. We know less about the Atlantic walrus, but 0:06:44.640 --> 0:06:47.920 they don't seem to migrate in the summer. When the 0:06:47.960 --> 0:06:51.800 ice melts and recedes, the Pacific females head north then 0:06:51.920 --> 0:06:56.040 return south before the ice freezes in the winter. Researchers 0:06:56.120 --> 0:06:58.279 aren't sure why the males don't migrate to the same 0:06:58.279 --> 0:07:01.679 extent that females do might have to do with sperm production. 0:07:03.000 --> 0:07:05.640 The herds meet in the winter. When the females head south, 0:07:06.360 --> 0:07:10.240 they'll congregate on an ice pack and basically be serenaded 0:07:10.280 --> 0:07:13.640 by the males, which inflate pouches near their throat to 0:07:13.720 --> 0:07:17.520 remain upright in the water and vocalize, clacking their teeth, 0:07:17.680 --> 0:07:20.840 whistling and making bell sounds until one of the females 0:07:20.880 --> 0:07:25.840 is impressed enough to come mate. Pregnancy lasts about fifteen months, 0:07:26.000 --> 0:07:28.800 so calves are born in the spring during migration north. 0:07:29.640 --> 0:07:32.520 Mothers are very protective of their young and may form 0:07:32.560 --> 0:07:36.880 a separate nursery herd with other cows. Females stay close 0:07:36.920 --> 0:07:39.640 to their newborns for at least a year and sometimes 0:07:39.680 --> 0:07:44.000 over two years, and may nurse that entire time. Cows 0:07:44.040 --> 0:07:46.440 often give their young rides on their backs, even though 0:07:46.480 --> 0:07:50.080 calves can usually swim after just a month or so. 0:07:50.120 --> 0:07:53.520 Those calves are big bundles of joy. They can weigh 0:07:53.520 --> 0:07:55.680 from one hundred to one hundred and sixty pounds of 0:07:55.720 --> 0:07:59.480 birth that's forty five to seventy five kilos. They tend 0:07:59.480 --> 0:08:01.600 to be darker than the adults in color and get 0:08:01.640 --> 0:08:07.040 lighter as they age. They're very social and seemingly smart creatures. 0:08:07.840 --> 0:08:11.160 Young males have been observed keeping watch over injured walruses 0:08:11.400 --> 0:08:14.320 and pushing dead or dying walruses off of ice floes 0:08:14.360 --> 0:08:18.560 so that nearby hunters can't get to them. Female walruses 0:08:18.600 --> 0:08:22.720 may also carry their dead young away from hunters. Though 0:08:22.760 --> 0:08:26.120 walruses have few natural predators, humans have hunted them for 0:08:26.320 --> 0:08:31.080 thousands of years for their meat, tusks, bones, skin, and oil. 0:08:32.320 --> 0:08:35.520 In the mid to late eighteen hundreds, in particular, walrus oil, 0:08:35.800 --> 0:08:39.400 created by boiling walrus blubber at high temperatures, was sought 0:08:39.440 --> 0:08:44.000 for lamps, soap, and as a machine lubricant. From eighteen 0:08:44.040 --> 0:08:47.319 sixty to eighteen eighty, some ten thousand walruses were killed 0:08:47.360 --> 0:08:51.640 every year in the Eastern Arctic alone. Walrus hunting has 0:08:51.679 --> 0:08:55.640 since been restricted generally only two native populations who have 0:08:55.760 --> 0:08:58.319 traditionally relied on the walrus as a source of food 0:08:58.480 --> 0:09:03.360 and other supplies. In Alaska, for example, peoples like the 0:09:03.360 --> 0:09:07.080 Inupia and the Upic have historically used every part of 0:09:07.080 --> 0:09:11.440 the animal. Stomachs can be made into containers and drums, 0:09:11.760 --> 0:09:15.320 a skins made into boat covers and rope, and ivory 0:09:15.520 --> 0:09:20.920 is used in art. Local management keeps harvests within sustainable limits. 0:09:21.880 --> 0:09:24.400 In the United States, the Marine Mammal Protection Act of 0:09:24.480 --> 0:09:27.920 nineteen seventy two protects the walrus from hunters and prohibits 0:09:27.920 --> 0:09:32.200 the trade of walrus ivory. Only ivory that predates the 0:09:32.280 --> 0:09:35.160 law or has been carved by an Alaska native can 0:09:35.280 --> 0:09:39.760 legally be sold. Other national and international laws protect the 0:09:39.800 --> 0:09:43.800 animals from harvest and restrict global trade of walrus products. 0:09:44.800 --> 0:09:49.600 These measures have stabilized walrus populations, but unfortunately they now 0:09:49.640 --> 0:09:56.040 face another threat, global warming. As Earth's average temperature increases, 0:09:56.440 --> 0:10:00.439 more and more ice in the polar region recedes. This 0:10:00.520 --> 0:10:03.880 could be devastating to walruses because they depend on the 0:10:03.880 --> 0:10:08.120 ice shelves as a resting ground between dives. The shallow 0:10:08.160 --> 0:10:11.480 waters where walruses like to feed now have little or 0:10:11.520 --> 0:10:14.480 no ice for mothers and babies to rest on when feeding. 0:10:15.640 --> 0:10:18.440 As a result, mothers may have to travel farther to 0:10:18.480 --> 0:10:22.439 reach feeding and resting grounds. This means they may become 0:10:22.480 --> 0:10:26.600 separated from their young. Areas that do have ice shelves 0:10:26.640 --> 0:10:29.640 are deeper, and the walruses aren't accustomed to diving that 0:10:29.760 --> 0:10:33.880 deep for food. Only time will tell whether the walrus 0:10:33.880 --> 0:10:37.160 can adapt to the longer commute and deeper dives required 0:10:37.440 --> 0:10:44.880 because of the ICE's retreat. Today's episode is based on 0:10:44.880 --> 0:10:47.920 the article how Walruses work on how stuffworks dot Com, 0:10:47.960 --> 0:10:51.079 written by Jennifer Wharton. Brain Stuff is production by Heart 0:10:51.160 --> 0:10:53.520 Radio in partnership with how Stuffwork dot Com and is 0:10:53.559 --> 0:10:56.920 produced by Tyler Klang. For more podcasts from My heart Radio, 0:10:57.240 --> 0:11:00.360 visit the heart Radio app, Apple Podcasts, or wherevery listen 0:11:00.400 --> 0:11:01.439 to your favorite shows.