1 00:00:01,840 --> 00:00:07,640 Speaker 1: Welcome to brain Stuff, a production of iHeartRadio. Hey brain Stuff. 2 00:00:07,640 --> 00:00:11,040 Speaker 1: I'm Lauren Vogelebomb, and this is a classic episode from 3 00:00:11,119 --> 00:00:15,400 Speaker 1: the Vault. Today's classic has to do with whales. They 4 00:00:15,440 --> 00:00:19,400 Speaker 1: are seemingly impossibly bigger than any of their cousins that 5 00:00:19,440 --> 00:00:23,520 Speaker 1: live on land for a few good reasons. But given those, 6 00:00:23,880 --> 00:00:29,760 Speaker 1: why aren't they even bigger? Hey brain stuff? Lauren Voglebomb. Here. 7 00:00:30,440 --> 00:00:33,320 Speaker 1: If you've ever been whale watching, visited a large aquarium, 8 00:00:33,440 --> 00:00:35,360 Speaker 1: or even seen the skeleton of a whale in a 9 00:00:35,440 --> 00:00:38,879 Speaker 1: museum of natural history, you know the majestic massiveness of 10 00:00:38,960 --> 00:00:42,280 Speaker 1: these aquatic mammals. The largest mammal to have ever lived 11 00:00:42,280 --> 00:00:44,360 Speaker 1: on Earth in the history of the planet is not 12 00:00:44,520 --> 00:00:48,239 Speaker 1: some prehistoric monstrosity. It's actually the blue whale, and is 13 00:00:48,280 --> 00:00:52,320 Speaker 1: alive right now swimming around in our oceans. Whales range 14 00:00:52,320 --> 00:00:54,600 Speaker 1: in size from the massive blue whales, which can grow 15 00:00:54,640 --> 00:00:57,240 Speaker 1: to more than ninety feet that's twenty seven meters in length, 16 00:00:57,440 --> 00:01:00,640 Speaker 1: to the relatively tiny pigmy sperm whales, which measure a 17 00:01:00,760 --> 00:01:04,200 Speaker 1: measly ten feet or three meters in length. But with 18 00:01:04,280 --> 00:01:07,160 Speaker 1: all that ocean to swim around in, why aren't whales 19 00:01:07,240 --> 00:01:09,840 Speaker 1: even bigger? It's not like they have to support their 20 00:01:09,840 --> 00:01:13,119 Speaker 1: big bodies on legs and walk around. For that matter, though, 21 00:01:13,319 --> 00:01:17,039 Speaker 1: why aren't they smaller? Both answers have to do with 22 00:01:17,160 --> 00:01:21,560 Speaker 1: food and heat. At least that's what researchers at Stanford 23 00:01:21,640 --> 00:01:24,440 Speaker 1: University found when they compiled the body mass data for 24 00:01:24,520 --> 00:01:28,360 Speaker 1: nearly four thousand living whales and three thousand fossilized species. 25 00:01:28,920 --> 00:01:32,240 Speaker 1: Their analysis determined that aquatic mammals actually face more size 26 00:01:32,280 --> 00:01:36,560 Speaker 1: constraints than their counterparts on land. The study authors determined 27 00:01:36,600 --> 00:01:39,120 Speaker 1: that there are two main factors why whales are big 28 00:01:39,200 --> 00:01:44,160 Speaker 1: but not bigger, heat loss and metabolism. Oceans can be 29 00:01:44,240 --> 00:01:47,880 Speaker 1: pretty cold places to live, and whales, while very intelligent, 30 00:01:48,120 --> 00:01:52,200 Speaker 1: don't really have the aquatic equivalent to thermal underwear. So 31 00:01:52,480 --> 00:01:55,120 Speaker 1: because they're warm blooded mammals, they have to be large 32 00:01:55,200 --> 00:01:57,560 Speaker 1: enough to keep from losing too much body heat to 33 00:01:57,680 --> 00:02:01,960 Speaker 1: the surrounding water thermoregulation. Then it keeps whales from being 34 00:02:01,960 --> 00:02:06,040 Speaker 1: the size of, say dogs. Study co author Jonathan Payne, 35 00:02:06,160 --> 00:02:09,240 Speaker 1: a professor of geological sciences at Stanford School of Earth, 36 00:02:09,360 --> 00:02:13,040 Speaker 1: Energy and Environmental Sciences, explained in a pressed statement, when 37 00:02:13,080 --> 00:02:15,720 Speaker 1: you're very small, you lose heat back into the water 38 00:02:15,880 --> 00:02:18,519 Speaker 1: so fast there's no way to eat enough food to 39 00:02:18,639 --> 00:02:22,560 Speaker 1: keep up. And speaking of eating, whales have to do 40 00:02:22,639 --> 00:02:25,880 Speaker 1: it a lot. Like all mammals, they convert that food 41 00:02:25,919 --> 00:02:29,880 Speaker 1: into energy for swimming, growing, and doing other whale like things. 42 00:02:30,360 --> 00:02:34,560 Speaker 1: That's the metabolic system at work. But the researchers suggest 43 00:02:34,639 --> 00:02:37,840 Speaker 1: that the metabolism of whales only gets faster as they 44 00:02:37,880 --> 00:02:41,120 Speaker 1: get bigger, and so they can only get so large. 45 00:02:41,760 --> 00:02:45,000 Speaker 1: Another study co author, Craig McLain of the Louisiana University's 46 00:02:45,040 --> 00:02:49,880 Speaker 1: Marine Consortium, explained it this way. Basically, animals are machines 47 00:02:49,919 --> 00:02:53,320 Speaker 1: that require energy to operate. This need for energy places 48 00:02:53,360 --> 00:02:56,080 Speaker 1: hard limits on what animals can do and how big 49 00:02:56,160 --> 00:03:00,000 Speaker 1: they can be. So it boils down to how much 50 00:03:00,000 --> 00:03:03,080 Speaker 1: which whales can eat versus their metabolic rate that keeps 51 00:03:03,080 --> 00:03:06,680 Speaker 1: whales from getting infinitely large. But how do those massive 52 00:03:06,680 --> 00:03:10,359 Speaker 1: blue whales get so massive? They have bay lean instead 53 00:03:10,400 --> 00:03:13,239 Speaker 1: of teeth and strain their food a little shrimp like 54 00:03:13,280 --> 00:03:17,040 Speaker 1: creatures called krill instead of chewing it. Krill are only 55 00:03:17,080 --> 00:03:20,000 Speaker 1: a few centimeters long, but they really add up. Every 56 00:03:20,080 --> 00:03:22,680 Speaker 1: day a blue whale eats about eight thousand pounds. That's 57 00:03:22,760 --> 00:03:26,480 Speaker 1: over three thousand, six hundred kilos of krill so blue 58 00:03:26,520 --> 00:03:28,640 Speaker 1: whales are not only the largest whales in the ocean, 59 00:03:28,800 --> 00:03:40,160 Speaker 1: they're also the most efficient eaters of all. Today's episode 60 00:03:40,200 --> 00:03:42,400 Speaker 1: is based on the article why are Whales so Big? 61 00:03:42,480 --> 00:03:46,200 Speaker 1: On HowStuffWorks dot com written by Kristin Halgeisler. Brainstuff is 62 00:03:46,240 --> 00:03:49,040 Speaker 1: production of iHeartRadio in partnership with how stuffworks dot Com 63 00:03:49,080 --> 00:03:51,840 Speaker 1: and is produced by Tyler Klang. The four more podcasts 64 00:03:51,880 --> 00:03:55,200 Speaker 1: my heart Radio, visit the iHeartRadio app, Apple Podcasts, or 65 00:03:55,240 --> 00:04:06,600 Speaker 1: wherever you listen to your favorite shows.