WEBVTT - How Do Octopuses Work? 0:00:01.840 --> 0:00:07.840 Welcome to Brainstuff, a production of iHeartRadio. Hey, Brainstuff, Lauren 0:00:07.840 --> 0:00:12.800 Bobblebaum here. But we humans are lucky that our sexual 0:00:12.840 --> 0:00:17.200 dimorphism is relatively mild. It certainly makes city planning easier. 0:00:18.320 --> 0:00:22.040 Consider the blanket octopus. A full grown male of the 0:00:22.079 --> 0:00:24.759 species is less than an inch long, only a couple 0:00:24.760 --> 0:00:28.960 of centimeters, and weighs less than a gram. The females 0:00:29.000 --> 0:00:31.400 can reach more than six feet or two meters in 0:00:31.480 --> 0:00:35.000 length and weigh one hundred pounds. That's forty five kilos. 0:00:35.880 --> 0:00:39.519 That means a female blanket octopus is some forty thousand 0:00:39.600 --> 0:00:43.800 times heavier than a male. In human terms, it would 0:00:43.800 --> 0:00:45.839 be like a man walking down the street with a 0:00:45.840 --> 0:00:48.320 woman who is four times the size of the Statue 0:00:48.360 --> 0:00:51.360 of Liberty, or a woman ringing up an order for 0:00:51.400 --> 0:00:55.160 a man the size of a beetle. Luckily, for the 0:00:55.200 --> 0:00:59.600 male blanket octopus, a mating is not a full contact sport. 0:01:00.120 --> 0:01:03.360 He has a modified arm that contains long rows of sperm. 0:01:03.960 --> 0:01:07.080 He simply tears off this arm and politely hands it 0:01:07.120 --> 0:01:10.559 to his mammoth mate, who then saves it for later use. 0:01:11.760 --> 0:01:13.840 These males have also been known to rip off the 0:01:13.959 --> 0:01:17.040 venomous tentacles of the Portuguese man O war and wield 0:01:17.040 --> 0:01:20.560 them as makeshift swords to ward off predators. This octopus 0:01:20.600 --> 0:01:24.360 is immune to the man o war's sting. And this 0:01:24.520 --> 0:01:28.720 is just one fascinating example of the octopod order, which 0:01:28.720 --> 0:01:32.120 contains over three hundred species, ranging in size from the 0:01:32.280 --> 0:01:35.640 quarter gram male blanket octopus to the six hundred pound 0:01:35.720 --> 0:01:39.040 plus giant Pacific octopus that's at least two hundred and 0:01:39.040 --> 0:01:44.080 seventy kilos. These invertebrates live only a few years, but 0:01:44.160 --> 0:01:49.560 they're seriously smart. They can camouflage themselves, solve puzzles, use tools, 0:01:49.800 --> 0:01:56.160 and even be sassy. Today, let's talk about octopuses, and yes, 0:01:56.240 --> 0:02:01.680 that is the scientifically preferred plural. The octopus belongs to 0:02:01.760 --> 0:02:06.080 the mollusk phylum, alongside slimy next of kin like clams, snails, 0:02:06.080 --> 0:02:11.160 and slugs. Within the phylum, octopuses are in the cephalopod class, 0:02:11.320 --> 0:02:14.560 which originated some six hundred million years ago and includes 0:02:14.639 --> 0:02:19.640 other advanced animals like squid and cuttlefish, but octopuses have 0:02:19.680 --> 0:02:23.600 evolved the most. While other cephalopods sport some form of 0:02:23.680 --> 0:02:27.760 inner or outer shell like their mollusc relatives, most octopuses 0:02:27.840 --> 0:02:33.160 have none. The word cephalopod means head footed. These animal's 0:02:33.320 --> 0:02:37.480 arms branch directly off of their heads. Some cephalopods have 0:02:37.560 --> 0:02:40.720 tentacles as well as arms, but the octopus manages just 0:02:40.840 --> 0:02:43.560 fine with the eight sucker studded arms it uses for 0:02:43.680 --> 0:02:49.680 practically everything, eating, moving, hunting, tasting, and mating. There are 0:02:49.760 --> 0:02:54.000 actually two suborders of octopus, the better known inserate and 0:02:54.160 --> 0:02:58.400 the more mysterious sirate. Serrate octopuses are named for the 0:02:58.440 --> 0:03:02.080 pairs of ccilia like strand along the suckers on their arms. 0:03:02.480 --> 0:03:05.280 They tend to live in deep cold water and don't 0:03:05.280 --> 0:03:08.280 adjust well to other conditions, meaning they're harder to study, 0:03:08.760 --> 0:03:10.920 though we've learned a lot about some species, like the 0:03:10.960 --> 0:03:15.560 dumbo octopus in recent years. Seriat octopuses do have a 0:03:15.560 --> 0:03:19.880 bit of an internal cartilage like shell. Both types of 0:03:19.880 --> 0:03:22.640 octopus will have a mouth at the center of its arms, 0:03:22.880 --> 0:03:25.760 and its doughnut shaped brain will sit just behind that, 0:03:26.080 --> 0:03:29.120 wrapped around the animal's esophagus sort of in the center 0:03:29.160 --> 0:03:32.519 of its body. That's where its two eyes are as well. 0:03:33.720 --> 0:03:36.640 The bulbous head of an octopus is actually what's called 0:03:36.680 --> 0:03:40.240 its mantle, a strongly muscled structure that protects the other 0:03:40.360 --> 0:03:44.720 organs its gills hearts. It has three hearts, digestive system 0:03:44.920 --> 0:03:49.600 and reproductive glands. Those three hearts come in handy because 0:03:49.640 --> 0:03:53.280 octopuses are adapted to survive in extreme temperatures and low 0:03:53.360 --> 0:03:58.800 oxygen environments. To cope, an octopus maintains a constant high 0:03:58.840 --> 0:04:02.440 blood pressure. Two of its hearts pump oxygen rich blood 0:04:02.480 --> 0:04:05.200 through the gills, while the third circulates it through the 0:04:05.240 --> 0:04:08.680 rest of the body. That blood is blue in color 0:04:08.800 --> 0:04:12.520 because it's copper based, not iron based like ours, which 0:04:12.560 --> 0:04:15.840 also makes it better at transporting oxygen in low temperatures. 0:04:17.040 --> 0:04:20.400 An octopus will also have a funnel, sometimes called a siphon, 0:04:20.640 --> 0:04:22.960 which is a tubular opening near the base of the 0:04:23.000 --> 0:04:25.560 mantle that serves as a jetway for water used for 0:04:25.640 --> 0:04:30.680 quick movement. Lacking a protective outer shell, the octopus has 0:04:30.720 --> 0:04:35.919 a startling array of defense mechanisms. They are masters of disguise. 0:04:36.520 --> 0:04:39.960 Cells in their skin called chromatophores, tens of thousands of 0:04:39.960 --> 0:04:44.920 them let them change color. These pigmented cells each contain 0:04:45.080 --> 0:04:48.600 three sacks of color and is surrounded by muscles that 0:04:48.720 --> 0:04:52.520 change how the pigment is displayed by relaxing or contracting 0:04:53.680 --> 0:04:57.000 it's sort of like a colorful design printed on a balloon. 0:04:57.600 --> 0:05:00.919 When the balloon is relaxed and uninflated, the design and 0:05:01.000 --> 0:05:05.279 its colors are smoothed and hidden. But when you stretch 0:05:05.320 --> 0:05:08.279 the balloon out by blowing it up, the colors become apparent, 0:05:08.640 --> 0:05:11.360 and you might be able to reveal different colors by 0:05:11.360 --> 0:05:15.840 expanding different parts of the balloon. The animal's nervous system 0:05:15.920 --> 0:05:20.599 can control each chromatophor independently, meaning color displays can be 0:05:20.720 --> 0:05:24.720 highly complex and quick. An octopus can change its appearance 0:05:24.880 --> 0:05:28.880 in less than a second. Also, areas on the skin 0:05:29.000 --> 0:05:33.040 called papilli can change size and texture from flat to 0:05:33.160 --> 0:05:36.160 bumpy to spiky to let the animal blend in with 0:05:36.360 --> 0:05:42.120 coral rocks, sand seaweed, and other stuff. The mimic octopus 0:05:42.160 --> 0:05:46.360 can even use color, shape, and movement to impersonate other animals. 0:05:47.000 --> 0:05:50.599 For example, it'll travel in a long, flatfish shape like 0:05:50.640 --> 0:05:53.760 the venomous banded soul, or wave an arm like a 0:05:53.800 --> 0:05:57.480 banded sea snake to make predators think twice about attacking 0:05:58.800 --> 0:06:04.400 and insert. Octopusses have another getaway mechanism, ink. The ink 0:06:04.480 --> 0:06:07.960 sack is located near the digestive system, and when necessary, 0:06:08.320 --> 0:06:10.839 the octopus can eject black ink out of the sack, 0:06:11.040 --> 0:06:13.640 along with the burst of water from its funnel, either 0:06:13.720 --> 0:06:16.400 in little blobs that serve as decoys, or in one 0:06:16.480 --> 0:06:19.920 bit mass like a smoke bomb, to obscure a quick getaway. 0:06:21.160 --> 0:06:24.160 The ink can also contain a compound that impairs smell 0:06:24.240 --> 0:06:30.760 and taste, to further confuse predators. Octopuses have excellent senses 0:06:30.800 --> 0:06:34.080 of sight and taste, partially because they have lots of 0:06:34.160 --> 0:06:39.120 processing power. An octopus's brain is proportionally larger than any 0:06:39.240 --> 0:06:44.039 other invertebrate, and smaller only than birds and mammals. The 0:06:44.080 --> 0:06:48.120 average octopus has as many neurons as a dog. Its 0:06:48.120 --> 0:06:51.080 central brain is only part of the story, though, Three 0:06:51.200 --> 0:06:54.440 fifths of the octopus's nerves are distributed throughout its arms 0:06:54.600 --> 0:06:57.839 to help it taste, touch, and move around its environment. 0:06:59.000 --> 0:07:03.040 Octopus arms are incredibly strong and flexible. Octopods have been 0:07:03.040 --> 0:07:07.599 known to wrestle sharks and break through plexiglass, and without 0:07:07.640 --> 0:07:10.760 all those pesky bones and joints that limit our movement, 0:07:11.320 --> 0:07:15.320 the arms have an almost infinite range of motion, and 0:07:15.760 --> 0:07:20.680 octopus arms have minds of their own. Literally, each has 0:07:20.760 --> 0:07:23.880 a cluster of nerve cells called a ganglion that works 0:07:23.920 --> 0:07:27.040 as a mini brain and allows the arm to act independently, 0:07:27.600 --> 0:07:31.440 though the central brain can take over. Our researchers think 0:07:31.480 --> 0:07:34.280 the brain can give an arm an assignment and then 0:07:34.480 --> 0:07:37.119 not have to think about it again unless something gets weird, 0:07:37.800 --> 0:07:40.160 like maybe the arm moves out of the water where 0:07:40.160 --> 0:07:43.240 it can no longer taste prey, so the octopus has 0:07:43.240 --> 0:07:47.400 to use its vision to guide the arm further. Next step, 0:07:47.520 --> 0:07:51.240 let's talk about octopus behavior. But first let's take a 0:07:51.320 --> 0:07:57.960 quick break for a word from our sponsors, and we're back. 0:07:58.080 --> 0:08:03.040 Thank you sponsors. Okay. Octopuses tend to spend much of 0:08:03.080 --> 0:08:07.040 their lives solitary in a den, leaving at night to hunt. 0:08:08.120 --> 0:08:11.040 An octopus might find a suitable den in a crevice 0:08:11.240 --> 0:08:14.760 or even a discarded bottle, or make one from objects 0:08:14.800 --> 0:08:19.160 like shells. When they do venture out, octopuses have a 0:08:19.200 --> 0:08:22.000 couple of ways to get around. If it needs to 0:08:22.000 --> 0:08:24.720 make a quick escape, it can jet away by taking 0:08:24.760 --> 0:08:27.880 water in through its mantle, sealing that water off, and 0:08:27.920 --> 0:08:32.040 then expelling it forcefully through its funnel. They've been clocked 0:08:32.040 --> 0:08:34.240 it up to twenty five miles an hour. That's forty 0:08:34.320 --> 0:08:39.040 kilometers an hour. Seriate Octopuses are less prolific at jetting, 0:08:39.280 --> 0:08:41.080 but they have a pair of fins coming off of 0:08:41.120 --> 0:08:45.319 their mantle that they can flap to move around. However, 0:08:45.679 --> 0:08:49.640 many octopuses prefer to walk along the seafloor with help 0:08:49.679 --> 0:08:53.160 from those rows of suckers on the underside of each arm. 0:08:53.760 --> 0:08:57.400 Each sucker has up to ten thousand sensory neurons, so 0:08:57.480 --> 0:08:59.800 the octopus can learn a lot about its surroundings this 0:08:59.800 --> 0:09:04.320 way and maybe chance upon a meal. Those long, flexible 0:09:04.400 --> 0:09:07.920 arms can reach into nooks after tasty crabs and clams, 0:09:08.200 --> 0:09:10.880 and their soft bodies are able to squeeze through tiny 0:09:10.920 --> 0:09:15.880 spaces after small fish. Octopuses don't have teeth as such 0:09:15.960 --> 0:09:19.160 to eat with, but they do have a hard, retractable 0:09:19.200 --> 0:09:22.280 beak similar in shape to a parrot's that can tear 0:09:22.280 --> 0:09:26.760 apart flesh or pry open shells. Behind the beak is 0:09:26.800 --> 0:09:29.480 the radula, which is a sort of barbed tongue the 0:09:29.520 --> 0:09:32.320 octopus can use to scrape meat out of a shell. 0:09:33.600 --> 0:09:36.760 It also has what's called a salivary papilla coming off 0:09:36.760 --> 0:09:40.240 of its salivary gland. This is a sort of secondary 0:09:40.280 --> 0:09:43.840 tongue with more toothy barbs that can drill through shell. 0:09:44.760 --> 0:09:47.720 The octopuses saliva can erode shell, and we can pray. 0:09:49.120 --> 0:09:52.520 In spite of being so clever and well built, octopuses 0:09:52.640 --> 0:09:56.600 only live an average of three to five years. Most 0:09:56.640 --> 0:09:59.800 will mate only once in their life and die soon afterwards, 0:10:00.320 --> 0:10:02.800 the male after a few months and the female after 0:10:02.840 --> 0:10:06.719 her eggs hatch. Not all of them detach an arm 0:10:06.760 --> 0:10:09.200 in the mating process, though the males do tend to 0:10:09.240 --> 0:10:13.400 have a modified arm for holding sperm. Either way, once 0:10:13.440 --> 0:10:16.760 the female receives sperm, she lays her eggs or applies 0:10:16.800 --> 0:10:19.320 it to her laid eggs if she's been saving a 0:10:19.320 --> 0:10:24.040 stray arm for the occasion. The female often cares meticulously 0:10:24.120 --> 0:10:27.360 for her eggs until they hatch, blowing water across them 0:10:27.440 --> 0:10:31.640 to keep them clean and protecting them from predators. The 0:10:31.640 --> 0:10:34.720 eggs might incubate from two to ten months or more, 0:10:35.120 --> 0:10:39.559 depending on the species and water temperature. Sometimes the female 0:10:39.559 --> 0:10:43.120 will forego eating to protect them, so once they hatch, 0:10:43.320 --> 0:10:47.400 there on their own. If it manages to survive predation, 0:10:47.720 --> 0:10:50.440 a young octopus may eat enough to increase its weight 0:10:50.520 --> 0:10:54.520 by five percent every day. After all, it doesn't have 0:10:54.600 --> 0:11:00.559 time to lose. And let's talk about those smarts. Octopuses 0:11:00.600 --> 0:11:04.200 are capable of thought, typically only observed in primates, and 0:11:04.360 --> 0:11:08.680 select other animals like crows in the wild. The giant 0:11:08.679 --> 0:11:12.600 Pacific octopus has been seen stealing crabs caught in traps 0:11:12.640 --> 0:11:15.600 by human fissures before the fissures can pull in their hull. 0:11:17.000 --> 0:11:20.360 The Pacific striped octopus uses a goatchia to catch shrimp. 0:11:20.840 --> 0:11:23.120 It'll sneak an arm around to poke the shrimp from 0:11:23.120 --> 0:11:26.120 one side, awaiting in the opposite direction to grab the 0:11:26.120 --> 0:11:30.079 shrimp when it darts away. The veined octopus is known 0:11:30.120 --> 0:11:33.400 to collect coconut shells and seashells, clean them off with 0:11:33.480 --> 0:11:36.920 jets of water, and carry them elsewhere to assemble a shelter. 0:11:38.480 --> 0:11:42.520 In captivity, octopuses have learned to solve mazes and puzzles 0:11:42.600 --> 0:11:47.320 and complete tasks to receive tasty rewards. They've been known 0:11:47.360 --> 0:11:50.600 to crawl out of their aquariums to sneak food from 0:11:50.679 --> 0:11:53.560 bins or other tanks, and then return to their home 0:11:53.600 --> 0:11:57.320 tank unassisted. Some can crawl across dry land for a 0:11:57.360 --> 0:12:03.040 limited period of time. Octopuses can recognize different humans faces 0:12:03.280 --> 0:12:07.280 and will react differently to them. There is an anecdote 0:12:07.320 --> 0:12:09.800 out of a University in New Zealand, where an octopus 0:12:09.840 --> 0:12:12.120 apparently took umbrage to one of the members of the 0:12:12.160 --> 0:12:14.800 staff and would squirt water at her every time she 0:12:14.880 --> 0:12:19.200 passed the tank. In another incident out of Pennsylvania, a 0:12:19.240 --> 0:12:22.679 researcher attempted to feed slightly stale squid to the octopuses 0:12:22.720 --> 0:12:26.040 in her lab, and one sent her a clear message. 0:12:26.480 --> 0:12:30.000 It made eye contact and used one arm to shove 0:12:30.080 --> 0:12:34.560 the squid down a nearby drain, effectively communicating that stale 0:12:34.679 --> 0:12:39.320 food would be discarded rather than eaten. Any animal that's 0:12:39.320 --> 0:12:42.480 smart enough to be a little rude is definitely impressive. 0:12:43.679 --> 0:12:46.880 The researchers are even looking into how we humans can 0:12:46.920 --> 0:12:50.920 mimic some of octopus's superpowers to build everything from better 0:12:50.960 --> 0:13:00.400 camouflage materials to soft, squishy robots. Today's episode based on 0:13:00.440 --> 0:13:03.600 the articles how Octopuses Work by Jennifer Horton and why 0:13:03.720 --> 0:13:07.120 is Octopus Blood Blue? Written by Lareel Dove on HowStuffWorks 0:13:07.160 --> 0:13:10.720 dot Com. A Brainstuff is production of iHeartRadio in partnership 0:13:10.720 --> 0:13:13.360 with HowStuffWorks dot Com and is produced by Tyler Klang. 0:13:14.080 --> 0:13:17.000 For more podcasts from my heart Radio, visit the iHeartRadio 0:13:17.040 --> 0:13:20.600 app Apple podcasts, or wherever you listen to your favorite shows.