WEBVTT - The Manta Ray, Part 2 0:00:03.000 --> 0:00:06.760 Welcome to Stuff to Blow Your Mind production of iHeartRadio. 0:00:12.680 --> 0:00:14.600 Hey you welcome to Stuff to Blow your Mind. 0:00:14.760 --> 0:00:17.560 My name is Robert Lamb and I am Joe McCormick, 0:00:17.600 --> 0:00:19.639 and we're back with part two in our series on 0:00:19.880 --> 0:00:24.480 manta rays and their close mobulate relatives. In the last 0:00:24.520 --> 0:00:27.520 episode of this series, we kicked things off by talking 0:00:27.560 --> 0:00:30.520 about an experience that you had rob recently where you 0:00:30.520 --> 0:00:33.919 and your family got to see reef manta rays in 0:00:33.920 --> 0:00:37.440 person while snorkeling in Indonesia, which sounds pretty amazing to 0:00:37.560 --> 0:00:39.000 get the details on that right. 0:00:39.040 --> 0:00:42.800 Correct, Yes, it was. It was amazing. Words can't quite 0:00:42.840 --> 0:00:43.400 describe it. 0:00:43.840 --> 0:00:46.800 Observing them, but not swimming quote with them, You weren't 0:00:46.800 --> 0:00:48.400 You weren't riding the rays. 0:00:48.159 --> 0:00:50.720 Correct, they were. They were doing their own thing. We 0:00:50.720 --> 0:00:54.520 were trying to keep our distance and observe from a distance, 0:00:54.800 --> 0:00:57.560 which which is the correct way of going about things. 0:00:57.920 --> 0:00:59.920 So that was what inspired us to talk about man 0:01:00.520 --> 0:01:02.840 in a series of episodes here on the show. In 0:01:02.880 --> 0:01:06.959 the last episode, we talked about the historical evolution of 0:01:07.080 --> 0:01:11.080 human attitudes toward manta rays with these old stories among 0:01:11.160 --> 0:01:15.080 some divers and sailors that cast manta rays as diabolical 0:01:15.200 --> 0:01:18.399 vampires of the sea. You know, there's one idea that 0:01:18.440 --> 0:01:21.320 they will like fold over a diver like a blanket 0:01:21.360 --> 0:01:24.640 of death. This, of course is not true, and since 0:01:24.840 --> 0:01:27.720 it seems like since roughly the nineteen seventies there has 0:01:27.760 --> 0:01:31.600 been more widespread recognition that mantas are gentle and not 0:01:31.800 --> 0:01:35.200 threatening to humans, though of course that has not stopped 0:01:35.280 --> 0:01:37.800 humans from threatening them, and we talked about all kinds 0:01:37.800 --> 0:01:41.440 of ways that human activity can hurt these animals. These 0:01:41.480 --> 0:01:45.160 impacts range from accidental harms, like when mantas are killed 0:01:45.200 --> 0:01:48.000 as bycatch in commercial fishing. It's not what people are 0:01:48.000 --> 0:01:50.120 fishing for, but they just get caught in nets and 0:01:50.120 --> 0:01:54.360 other lines and other things, all the way to intentional targeting, 0:01:54.680 --> 0:01:57.560 where they are killed for their gill plates, which some 0:01:57.600 --> 0:02:02.560 people falsely allege to have medical powers. And in the 0:02:02.680 --> 0:02:07.320 vein of talking about tall tales of mantas as vicious monsters, 0:02:07.360 --> 0:02:09.320 we also discussed a couple of movies made in the 0:02:09.440 --> 0:02:12.680 nineteen thirties that have a killer Manta Ray or devil 0:02:12.720 --> 0:02:13.840 Ray as the monster. 0:02:14.560 --> 0:02:17.080 I didn't mention this in that episode, but it's worth 0:02:17.160 --> 0:02:20.600 noting that, you, of course have one of Aquaman's arch 0:02:20.720 --> 0:02:23.680 Enemies is Black Manta. Oh, so you know, it's the 0:02:23.680 --> 0:02:27.040 perfect mantle for a villain that was conceived. I believe 0:02:27.080 --> 0:02:30.200 in this era you also have Man Ray, which is 0:02:30.520 --> 0:02:33.280 a villain based on Black Manta that pops up on 0:02:33.320 --> 0:02:37.720 SpongeBob SquarePants, not to be confused with the artist Man Ray. 0:02:38.160 --> 0:02:43.040 I think Black Manta is actually in the Aquaman movie 0:02:43.040 --> 0:02:44.880 with cal Drogo in it, isn't it. 0:02:45.040 --> 0:02:48.519 Oh yeah, yeah, who plays Black Manta? I don't I 0:02:48.560 --> 0:02:49.840 haven't seen any of those films. 0:02:49.919 --> 0:02:51.880 I don't remember any of the cast of that movie 0:02:51.880 --> 0:02:55.040 except in Nicole Kidman in a really funny looking costume. 0:02:56.000 --> 0:02:58.680 So I you know, folks out there, No, I'm not 0:02:58.720 --> 0:03:01.840 the biggest superhero movie fan. I haven't kept up with 0:03:01.880 --> 0:03:04.880 all of the Marvel and DC superhero films, but I 0:03:04.880 --> 0:03:08.240 think I watched Aquaman on a plane for some reason. 0:03:08.760 --> 0:03:12.200 I remember thinking it was really funny, like highly amusing. 0:03:12.880 --> 0:03:15.680 Oh no, wait, I remember another cast member had Patrick 0:03:15.720 --> 0:03:18.480 Wilson like riding on a shark and saying, you will 0:03:18.520 --> 0:03:20.400 call me ocean Master. 0:03:22.400 --> 0:03:24.239 I need to watch those on an airplane sometime. 0:03:24.320 --> 0:03:27.400 Yes, Jason Momoa, I'm sorry I called him Caldroco. 0:03:27.560 --> 0:03:30.160 That's not nice. His name is Jason Momoa. 0:03:30.560 --> 0:03:37.160 Suffice to say, however, the Western American European conceptions of 0:03:37.200 --> 0:03:42.240 the manta ray and related species have evolved since basically 0:03:42.280 --> 0:03:45.839 the nineteen seventies. The nineteen seventies onward. Everyone has come 0:03:45.880 --> 0:03:49.760 to realize that manta rays are peaceful giants of the 0:03:49.800 --> 0:03:52.560 ocean and they are not out to eat us. 0:03:52.480 --> 0:03:55.160 Right, And so we also talked about modern conservation efforts 0:03:55.160 --> 0:03:58.400 aimed at protecting manta's You know, we got into like 0:03:58.440 --> 0:04:00.880 the cost benefit analysis that has to be done if 0:04:00.880 --> 0:04:04.880 you're considering building something like an ecological tourism trade around them. 0:04:04.920 --> 0:04:09.000 You know, there are risks but also potentially rewards. And 0:04:09.080 --> 0:04:11.720 we also talked about the basic biology of manta rays 0:04:11.760 --> 0:04:15.480 and their near relatives, their near relatives being the devil rays. 0:04:15.600 --> 0:04:19.039 Mantas and devil rays together make up the genus Mobula. 0:04:19.760 --> 0:04:23.400 And we got into subjects including their body design, common 0:04:23.480 --> 0:04:27.920 feeding strategies, and leaping or breaching behavior where they jump 0:04:28.000 --> 0:04:29.800 out of the water and slap back down. We talked 0:04:29.800 --> 0:04:32.320 about some reasons they might do that. And we're back 0:04:32.360 --> 0:04:33.479 today to talk about more. 0:04:33.920 --> 0:04:35.760 Yeah, and we're gonna we're gonna pick up in an 0:04:35.800 --> 0:04:38.800 interesting area, you're gonna you're gonna get into some some 0:04:38.960 --> 0:04:42.920 more myths or potential myths about their behavior and what 0:04:43.040 --> 0:04:45.320 we may or may not know about those behaviors. 0:04:45.360 --> 0:04:48.520 Now right, well, I think this might be slightly different 0:04:48.520 --> 0:04:53.120 because it would be truths about their behavior with mythical interpretations, 0:04:53.400 --> 0:04:57.040 if that makes any sense. So in the last episode, 0:04:57.080 --> 0:04:59.919 we were talking about these incorrect folk beliefs about the 0:05:00.080 --> 0:05:02.640 man you know that they would attack boats or attack 0:05:02.800 --> 0:05:06.960 divers in the form of this underwater death blanket. And 0:05:07.240 --> 0:05:10.080 as a source there I referenced an old article called 0:05:10.120 --> 0:05:12.960 the Story of the Devilfish from the ear Way back 0:05:13.000 --> 0:05:16.720 in the year nineteen ten by the American biologist Theodore 0:05:16.800 --> 0:05:19.280 gil There was another thread in this article that I 0:05:19.360 --> 0:05:21.760 found interesting and I wanted to come back to it today. 0:05:21.800 --> 0:05:25.480 So if you'll recall from last time, in this article Gil, 0:05:25.839 --> 0:05:29.120 he's very dismissive of the belief that the manta tries 0:05:29.160 --> 0:05:32.359 to smother divers with its body or devour them with 0:05:32.440 --> 0:05:35.160 its gaping mouth. He points out that the manta is 0:05:35.200 --> 0:05:38.960 a filter feeder which eats tiny planktonic organisms. It does 0:05:39.000 --> 0:05:42.760 not eat large prey. There's no evidence of manta's targeting 0:05:42.839 --> 0:05:45.520 humans for violence, and they don't even have the right 0:05:45.560 --> 0:05:48.520 biological equipment to eat us if they were going to 0:05:48.560 --> 0:05:50.520 try to do that, which they're not going to try. 0:05:51.400 --> 0:05:53.960 But there is another part of the manta's more frightening 0:05:54.520 --> 0:05:58.240 reputation in pre modern times, which is the belief that 0:05:58.279 --> 0:06:03.000 mantas will attack boats, not divers, but boats, particularly the 0:06:03.040 --> 0:06:07.080 claim that a manta will drag a boat out to 0:06:07.200 --> 0:06:10.839 sea by the anchor line. So here I'm going to 0:06:10.880 --> 0:06:14.479 read a passage from Gill's article quote in one of 0:06:14.520 --> 0:06:18.080 the earliest Notices of the Devilfish by John Lawson in 0:06:18.160 --> 0:06:23.160 the History of Carolina seventeen fourteen. This peculiarity is described 0:06:23.520 --> 0:06:26.560 the devilfish, he says, has been known to weigh a 0:06:26.600 --> 0:06:29.680 ship's anchor and run with the vessel a league or 0:06:29.680 --> 0:06:32.839 two and bring her back against tide to almost the 0:06:32.880 --> 0:06:36.240 same place. But then the quote ends, and Gill goes 0:06:36.240 --> 0:06:38.880 on to say later notices do not give the animal 0:06:38.880 --> 0:06:43.159 credit for the same accommodating treatment, And he later alludes 0:06:43.160 --> 0:06:46.560 to these other accounts that tell of the devilfish pulling 0:06:46.640 --> 0:06:49.920 sailing boats around by the anchor, to the wonder and 0:06:50.080 --> 0:06:54.200 fear of the sailors, and he also cites a more 0:06:54.240 --> 0:06:56.360 recent source to him at the time of his writing. 0:06:56.600 --> 0:07:00.760 This was a French naturalist named Leon de Guett describing 0:07:00.800 --> 0:07:04.080 the activity of pearl fishers in the Gulf of California 0:07:04.160 --> 0:07:08.880 in a text from eighteen ninety eight, and according to Deget, 0:07:09.000 --> 0:07:12.520 when fishers are caught out at sea overnight in the 0:07:12.520 --> 0:07:17.320 Gulf of California away from their usual mooring places, he says, 0:07:17.400 --> 0:07:21.280 they will always drop two anchors because they fear that 0:07:21.360 --> 0:07:23.800 if they only drop one, the anchor line will be 0:07:23.920 --> 0:07:26.720 seized by the devilfish in the dark, and thus the 0:07:26.720 --> 0:07:29.960 boat will be carried away into the open sea. And 0:07:30.040 --> 0:07:33.120 to get back to this up with his own observation, 0:07:33.400 --> 0:07:36.240 telling a story of how he was sent out to 0:07:36.520 --> 0:07:39.800 harpoon a specimen of a devil ray for the Natural 0:07:39.840 --> 0:07:44.440 History Museum of Paris, and he says, quote, after one 0:07:44.480 --> 0:07:47.880 had been harpooned, it turned back on the boat, seized 0:07:47.920 --> 0:07:50.280 the bow with its head fins, and held it in 0:07:50.320 --> 0:07:54.640 its clasp till it was lanced the second time. So 0:07:54.720 --> 0:07:59.200 that's Deget's account. But Gil says even this direct observation 0:08:00.000 --> 0:08:02.720 does not really lend credence to the idea that Mantas 0:08:02.800 --> 0:08:09.320 or devil rays deliberately attack detain or hijack boats because, 0:08:09.440 --> 0:08:12.080 based on his own study, Gil writes that this kind 0:08:12.160 --> 0:08:15.760 of grasping with the headfins is automatic. He says, it's 0:08:15.800 --> 0:08:20.280 an involuntary muscular reaction when something is in front of 0:08:20.320 --> 0:08:23.520 the ray's mouth, so in this case, it might happen 0:08:23.560 --> 0:08:26.880 to be the bow of the harpooner's boat. And so 0:08:27.040 --> 0:08:29.920 even when it's being attacked by somebody on the boat, 0:08:29.960 --> 0:08:32.320 when it's being harpooned, Gill argues that the ray was 0:08:32.320 --> 0:08:36.000 probably not actually trying to harm the boat, but rather 0:08:36.160 --> 0:08:38.960 was just being pulled toward the boat by the tension 0:08:38.960 --> 0:08:41.079 of the rope on the harpoon it had just been 0:08:41.160 --> 0:08:44.920 lanced with. And even to get himself the person originally 0:08:44.960 --> 0:08:47.760 telling the story of it seizing the bow of the boat, 0:08:48.120 --> 0:08:52.360 he says the devilfishes are generally timid, non aggressive animals. 0:08:53.080 --> 0:08:57.120 Though then after saying this confusingly to get does seem open, 0:08:57.320 --> 0:09:00.520 he sort of opens up more claims of devilfish savagery 0:09:01.080 --> 0:09:04.760 and alleges that in the Gulf of California, quote numerous 0:09:04.800 --> 0:09:08.079 cases have occurred of death resulting to divers as well 0:09:08.120 --> 0:09:11.640 as bathers from encounters with the devilfish or manta as 0:09:11.679 --> 0:09:14.320 the men call it. On the other hand, the carcasses 0:09:14.360 --> 0:09:16.800 of many that are killed are used for bait for 0:09:16.880 --> 0:09:20.920 other fishes. The strange detail to include. 0:09:21.320 --> 0:09:24.840 Yeah, yeah, I mean all of this is a pardon 0:09:26.040 --> 0:09:28.080 the terminology here, fishy because. 0:09:27.880 --> 0:09:30.240 Dobous third hand Yeah. 0:09:30.000 --> 0:09:32.240 Yeah, I mean, because everything we know and have been 0:09:32.280 --> 0:09:36.200 discussing about rays, when they're threatened, they use a burst 0:09:36.200 --> 0:09:40.760 of speed, they get away. That's their major way of 0:09:40.800 --> 0:09:43.760 defending themselves. So it doesn't really make sense based on 0:09:43.800 --> 0:09:45.640 what we know that they would turn around an attack 0:09:45.679 --> 0:09:49.280 of a ship or a boat, even if they are 0:09:49.320 --> 0:09:51.479 being acted upon with harpoons. 0:09:51.800 --> 0:09:54.320 Right, And as we discussed last time, of course, they 0:09:54.320 --> 0:09:58.120 are large animals, and any large animal could potentially hurt 0:09:58.120 --> 0:10:00.520 you just by bumping into you. Wrong, But there is 0:10:00.640 --> 0:10:04.160 really no evidence I could find of manta's being aggressive 0:10:04.200 --> 0:10:07.679 toward humans except for these like old third hand stories. 0:10:08.400 --> 0:10:08.760 Yeah. 0:10:08.800 --> 0:10:12.240 And I don't know if Gil gets into this or not, 0:10:12.280 --> 0:10:15.079 but for one of the things with you get into 0:10:16.240 --> 0:10:20.280 oral histories of things like the devilfish the manta, you 0:10:20.360 --> 0:10:22.480 end up having to ask questions, well, is the manta 0:10:22.480 --> 0:10:25.240 in this story, even if there's a kernel of truth 0:10:25.280 --> 0:10:28.320 to it, Is it indeed talking about the species that 0:10:28.360 --> 0:10:30.560 we are talking about as the manta ray, or is 0:10:30.559 --> 0:10:32.520 it referring to something else real or imagined. 0:10:32.720 --> 0:10:35.960 Yeah, so, even back in nineteen ten, Gil to me 0:10:36.040 --> 0:10:40.320 seems skeptical of these claims about it attacking boats. Certainly, 0:10:40.360 --> 0:10:44.320 modern researchers are skeptical of these stories of manterray aggression 0:10:44.320 --> 0:10:48.400 towards boats. But to the question of dragging boats specifically 0:10:48.440 --> 0:10:52.080 by the anchor cable, is this just a tall tale 0:10:52.320 --> 0:10:55.400 like the manta ray death blanket story or is there 0:10:55.400 --> 0:10:57.840 something more to that? Is there any modern evidence of 0:10:57.880 --> 0:11:00.360 things like this happening sort of? 0:11:00.360 --> 0:11:01.080 This is yes. 0:11:01.679 --> 0:11:05.120 For example, I found a Reuter's article from February eleventh, 0:11:05.240 --> 0:11:08.880 nineteen ninety nine, called motor boat no match for manta 0:11:09.000 --> 0:11:10.080 ray in tug of war. 0:11:10.720 --> 0:11:14.840 Well, I generally, you know, I generally trust Reuters in 0:11:14.880 --> 0:11:18.920 their reporting. Though usual usually I'm not reading about the 0:11:18.960 --> 0:11:22.319 marine biology. When I'm reading Reuters. Usually it's a nice 0:11:22.480 --> 0:11:27.240 you know, doom scroll into the abyss. So I missed 0:11:27.240 --> 0:11:28.840 this one when it came out. If I was in 0:11:28.840 --> 0:11:30.400 fact reading Routers at the time. 0:11:30.400 --> 0:11:32.319 I'll read from the beginning of the article and then 0:11:32.360 --> 0:11:34.320 summarize some other parts of it and we can make 0:11:34.400 --> 0:11:36.240 up our minds about it. Okay, what's going on here? 0:11:36.280 --> 0:11:40.320 So Dateline New Smurta Beach, Florida. Two Florida boaters met 0:11:40.320 --> 0:11:43.800 a real sea monster when their craft was dragged for 0:11:43.920 --> 0:11:46.400 hours by a powerful creature that turned out to be 0:11:46.480 --> 0:11:51.000 a giant manta ray, the Coastguard said Wednesday. Coastguard Petty 0:11:51.040 --> 0:11:54.480 Officer Scott Barnes said the agency received a radio distress 0:11:54.520 --> 0:11:57.480 call from a sixteen foot boat that reported it was 0:11:57.559 --> 0:12:01.280 being dragged by its anchor line by something unknown. The 0:12:01.320 --> 0:12:04.360 Coast Guard sent a rescue boat to investigate and found 0:12:04.440 --> 0:12:06.920 the motor boat was being dragged in circles by something 0:12:06.960 --> 0:12:10.320 beneath the surface. The crew transferred the anchor line to 0:12:10.480 --> 0:12:13.400 the Coastguard vessel, freeing the men in the motor boat, 0:12:13.520 --> 0:12:16.120 who had tried to use their ninety horsepower engine to 0:12:16.160 --> 0:12:19.120 go in reverse and stop themselves from being dragged out 0:12:19.160 --> 0:12:23.120 to sea. After the Coastguard's forty one foot boat pulled 0:12:23.160 --> 0:12:26.240 the anchor line for several minutes, a giant manta ray, 0:12:26.320 --> 0:12:30.240 measuring an estimated eighteen feet in width, came to the surface, 0:12:30.559 --> 0:12:32.599 and then the article goes on to describe how the 0:12:32.640 --> 0:12:36.320 coastguard struggled to pull the rope away. Eventually, the manta 0:12:36.400 --> 0:12:39.400 was able to disentangle itself from the rope and it 0:12:39.480 --> 0:12:41.800 swam away on its own, And by the end of 0:12:41.840 --> 0:12:45.040 the ordeal, the manta, they estimated, had pulled the boat 0:12:45.040 --> 0:12:47.760 for almost two hours, taking it about a mile and 0:12:47.800 --> 0:12:52.120 a half away from shore. But you could easily get 0:12:52.160 --> 0:12:55.440 the wrong idea about this, thinking that it supports this 0:12:55.600 --> 0:12:59.720 old notion that mantas will attack boats, that they are 0:12:59.760 --> 0:13:03.680 doing this on purpose, they're trying to drag the sailors 0:13:03.679 --> 0:13:06.600 out to sea, out to their deaths or something. From 0:13:06.600 --> 0:13:10.080 what I've read, there is absolutely zero evidence to support 0:13:10.080 --> 0:13:12.880 the idea that the mantas are acting aggressively when they 0:13:12.880 --> 0:13:16.840 pull a boat by the anchor line. The zero evidence 0:13:16.840 --> 0:13:20.840 that they're acting aggressively or even acting intentionally. Rather, this 0:13:20.960 --> 0:13:24.400 is almost certainly a case of mantas getting stuck. They 0:13:24.400 --> 0:13:29.200 are getting tangled in underwater ropes and chains by accident 0:13:29.600 --> 0:13:32.160 and then pulling the boat because they are unable to 0:13:32.200 --> 0:13:35.600 free themselves. And when you look at their heads, you 0:13:35.640 --> 0:13:37.440 look up a picture of a manta ray or a 0:13:37.440 --> 0:13:40.760 devil ray. You can see how this might easily happen. 0:13:40.960 --> 0:13:45.079 They almost have biological mooring cleats with their cephalic fins. 0:13:45.559 --> 0:13:56.599 Yeah, yeah, you can imagine them catching the line. 0:13:58.160 --> 0:14:01.120 For one more example of a mod encounter, I found 0:14:01.120 --> 0:14:04.400 a video on YouTube that the title begins with Giant 0:14:04.440 --> 0:14:08.880 mantray tangled in anchorchain, forty miles off shore. This is 0:14:09.240 --> 0:14:11.760 a video of some people out in a fishing boat 0:14:12.080 --> 0:14:14.959 in the Gulf of Mexico and a manta does get 0:14:15.000 --> 0:14:17.600 caught in their anchor line. Like it looks when you 0:14:17.600 --> 0:14:20.360 can see it, it looks like the line is not just 0:14:20.400 --> 0:14:24.000 caught between the cephalic fins, but kind of wrapped around them, 0:14:24.200 --> 0:14:27.160 like the lobes on its head have the line going 0:14:27.200 --> 0:14:31.080 across as well as between, and you can see it 0:14:31.120 --> 0:14:33.640 struggling at a couple of points. 0:14:33.360 --> 0:14:34.000 In this video. 0:14:34.360 --> 0:14:37.640 It quite strangely, almost seems to like be coming up 0:14:37.680 --> 0:14:40.400 to the surface and holding still while the fishermen are 0:14:40.440 --> 0:14:43.200 trying to get it untangled. That weirdly kind of matches. 0:14:43.240 --> 0:14:45.400 But then I don't know how to interpret what I'm 0:14:45.400 --> 0:14:47.600 seeing there, so maybe it shouldn't be taken this way, 0:14:47.880 --> 0:14:49.960 but it kind of reminds me of all these stories 0:14:50.320 --> 0:14:53.680 people talk about of manter rays being very like kind 0:14:53.720 --> 0:14:56.200 of slow moving and gentle while they come up to 0:14:56.200 --> 0:14:59.040 them and almost kind of letting people, you know, interact 0:14:59.160 --> 0:15:01.800 with them. Again, not encouraging people to do that unless 0:15:01.800 --> 0:15:04.080 you're trying to free one from a problem you've created. 0:15:04.640 --> 0:15:06.280 But anyway, in the end here the people in the 0:15:06.280 --> 0:15:09.960 boat are able to succeed by they sever the line 0:15:09.960 --> 0:15:13.200 in one place and that allows them to get it 0:15:13.280 --> 0:15:16.440 unwrapped from around the manta, and they let the manta 0:15:16.480 --> 0:15:18.560 swim away. So it seems like the manta gets away 0:15:18.600 --> 0:15:21.160 in the end of this, which is heartwarming. In fact, 0:15:21.240 --> 0:15:23.440 all these like bro fishermen are like high five in 0:15:23.480 --> 0:15:27.000 each other. They're like, yeah, we did it. 0:15:26.760 --> 0:15:27.520 It's it's sweet. 0:15:27.800 --> 0:15:30.520 But once again seems like a quite clear case of 0:15:30.560 --> 0:15:32.920 like the manta is not doing this on purpose. It's 0:15:32.960 --> 0:15:35.480 not it's not out here today thing say, and I'd 0:15:35.560 --> 0:15:37.880 like to drag a boat around it ended up in 0:15:37.920 --> 0:15:39.560 this situation against its will. 0:15:40.000 --> 0:15:44.280 Yeah, yeah, like you said, the cephalic fins are kind 0:15:44.280 --> 0:15:47.920 of look like natural line catchers, and then they're also 0:15:48.000 --> 0:15:51.120 just quite i mean they're they're wing shaped, they're they're 0:15:51.160 --> 0:15:54.720 they're quite wide. We've talked about their their wingspans, and yeah, 0:15:54.720 --> 0:15:57.600 that's just more real estate to potentially run into a line. 0:15:57.720 --> 0:15:57.920 Yeah. 0:15:57.960 --> 0:16:01.040 And so Gil talks about this in his article and 0:16:01.200 --> 0:16:04.640 says that these the cephalic fins or cephalic lobes, the 0:16:04.720 --> 0:16:08.920 kind of horns of the devilfish. They they're like an 0:16:08.920 --> 0:16:11.880 elephant's trunk. He he quotes another author saying that then 0:16:12.120 --> 0:16:14.600 they can kind of grasp objects and pull them in. 0:16:14.960 --> 0:16:18.480 He says they tend to rapidly kind of close in 0:16:18.560 --> 0:16:21.560 around the mouth when something appears in front of the mouth, 0:16:22.760 --> 0:16:28.120 and that the fish will have a kind of obstinacy in, 0:16:28.520 --> 0:16:31.360 you know, refusing to release things that go in like that. 0:16:32.320 --> 0:16:35.560 Gil says quote that these arms are muscular and powerful 0:16:35.600 --> 0:16:39.000 has been demonstrated on many occasions. The natural movement of 0:16:39.040 --> 0:16:42.520 the head fins or corropteries is inward, and when any 0:16:42.560 --> 0:16:46.440 object strikes between them, it is instinctively held a proceeding 0:16:46.480 --> 0:16:50.000 which explains the undoubted fact that these fishes can run 0:16:50.040 --> 0:16:55.040 away with quite large vessels. So Gil's chalking this up 0:16:55.080 --> 0:16:59.360 to involuntary motion of the strong cephalic fins closing over 0:16:59.440 --> 0:17:02.200 things that in the front of the mouth, which occasionally 0:17:02.400 --> 0:17:06.240 in some unlucky circumstances just happens to be an anchor line. 0:17:07.359 --> 0:17:11.120 I think gil is absolutely correct that these boat dragging 0:17:11.119 --> 0:17:14.320 incidents are not aggressive or intentional on the part of 0:17:14.359 --> 0:17:17.399 the ray, but is he correct about the mechanism. I 0:17:17.440 --> 0:17:20.280 was looking for modern sources and couldn't really find anything 0:17:20.320 --> 0:17:24.879 to confirm or deny his ideas there about the specific 0:17:25.000 --> 0:17:29.639 motion of the cephalic fins being involved. But I did 0:17:29.680 --> 0:17:34.640 find some commentary from more recent marine biology resources, specifically 0:17:34.880 --> 0:17:37.880 something from the organization known as the Manta Trust, which 0:17:37.880 --> 0:17:42.520 has a page on the subject of manta mooring line entanglements, 0:17:43.200 --> 0:17:47.679 and they highlight some different biological facts which make mooring 0:17:47.720 --> 0:17:52.920 line entanglements common for manta rays. Manta rays, like their 0:17:52.960 --> 0:17:59.159 cousins sharks, and also like tuna, are obligate ram ventilators, 0:17:59.400 --> 0:18:04.560 meaning they do not have the biological equipment needed to 0:18:04.880 --> 0:18:08.800 pump water over their gills when their bodies are at rest. 0:18:09.320 --> 0:18:12.040 So in order to make water flow over their gills 0:18:12.119 --> 0:18:14.760 so they can extract oxygen from the water and breathe, 0:18:15.119 --> 0:18:18.359 they have to move their bodies. So you've probably heard 0:18:18.359 --> 0:18:20.959 before that if a shark is forced to hold still, 0:18:21.080 --> 0:18:23.919 it will die. It has to swim to breathe. That 0:18:24.119 --> 0:18:27.080 is essentially true, and it's true for mantas as well. 0:18:28.000 --> 0:18:30.280 Fish that don't have to keep moving to breathe have 0:18:30.359 --> 0:18:33.440 what's known as a buckle pump system, where you use 0:18:33.600 --> 0:18:37.040 muscles around your mouth and throat to pump fresh water 0:18:37.240 --> 0:18:40.320 over the gills. Mantis don't have that. They've got to swim. 0:18:40.480 --> 0:18:42.080 Now, I do want to point out that Joe said 0:18:42.200 --> 0:18:46.280 essentially true of sharks, so we can get into a 0:18:46.320 --> 0:18:49.480 deeper discussion maybe in another episode where we talk about 0:18:49.640 --> 0:18:53.760 the different behaviors of different types of sharks. You do 0:18:53.880 --> 0:18:56.280 have some shark varieties that live in close to the 0:18:56.320 --> 0:18:58.840 reef that are going to be that can be still 0:18:58.880 --> 0:19:00.000 for extended periods of time. 0:19:00.080 --> 0:19:03.720 Yeah, they might actually have the buckle pumping equipment. But yeah, 0:19:03.760 --> 0:19:08.480 like great white charts, for example, don't they're ram ventilators exactly. 0:19:08.560 --> 0:19:11.040 Yes, absolutely true of great whites. 0:19:11.440 --> 0:19:13.879 But anyway, certainly true of manta rays. They have to 0:19:13.920 --> 0:19:16.919 swim in order to breathe. They are also ram ventilators. 0:19:17.359 --> 0:19:19.959 And so this means that getting entangled in a line 0:19:20.040 --> 0:19:22.640 can be deadly to a manta if it is stuck 0:19:22.760 --> 0:19:26.360 and it can't swim, around, it can't really breathe, and 0:19:26.560 --> 0:19:30.360 this might also explain why a manta would keep swimming 0:19:30.520 --> 0:19:33.160 even when it has a boat dragging behind it. It 0:19:33.280 --> 0:19:36.080 kind of has to swim. Pair this with a couple 0:19:36.080 --> 0:19:40.960 of other biological facts. Mantas can't swim backwards. You know, 0:19:41.000 --> 0:19:43.920 they are highly maneuverable fish in a way. They can 0:19:44.240 --> 0:19:45.920 turn around and you see them in the water doing 0:19:45.960 --> 0:19:50.960 these beautiful summersalts and everything, but it's always with forward motion, 0:19:51.400 --> 0:19:55.000 which usually means that the line just gets even more 0:19:55.080 --> 0:19:58.000 tangled up on them as they twist and somer salt 0:19:58.040 --> 0:20:01.000 around and they would need to really be able to 0:20:01.119 --> 0:20:03.760 back up to release the line, but they can't back up. 0:20:04.800 --> 0:20:05.320 Great point. 0:20:05.760 --> 0:20:08.320 The other thing is that the manta trust says is 0:20:08.400 --> 0:20:11.600 they are often not able to see the thin line 0:20:11.640 --> 0:20:14.000 of a rope or a chain when it's directly in 0:20:14.040 --> 0:20:17.000 front of them. And so you put all this together 0:20:17.520 --> 0:20:20.560 and it easily explains how mantas can get tangled in 0:20:20.720 --> 0:20:24.120 mooring lines and can end up pulling whatever these lines 0:20:24.160 --> 0:20:27.520 are attached to. This is usually not threatening to humans, 0:20:27.560 --> 0:20:30.399 but it is very threatening to the ray. Rays often 0:20:30.440 --> 0:20:33.840 asphyxiate and die when they get caught in moorings, and 0:20:33.920 --> 0:20:36.440 so the Manta Trust has this document where they make 0:20:36.520 --> 0:20:39.959 recommendations for making mooring lines safer for mantas. You can 0:20:40.000 --> 0:20:42.439 actually look this document up on their website for the 0:20:42.640 --> 0:20:46.960 full recommendations, but they suggest a few measures, like one 0:20:47.080 --> 0:20:52.000 just reducing the presence of especially loose line in the water. 0:20:52.200 --> 0:20:55.119 Loose or slack lines are more dangerous to raise than 0:20:55.200 --> 0:20:58.639 tight lines. You can probably kind of imagine where they are, 0:20:58.680 --> 0:21:00.760 like a looser line is easier to get fully just 0:21:00.800 --> 0:21:03.399 tangled up in or as a taut line, you know, 0:21:03.480 --> 0:21:05.800 you might more likely bump into and then something can 0:21:05.840 --> 0:21:11.800 get Yeah. But then also they recommend this interesting system 0:21:11.880 --> 0:21:13.520 that I don't know if I would have thought of this, 0:21:13.600 --> 0:21:18.240 but this is cool. They recommend attaching cable ties that 0:21:18.440 --> 0:21:22.119 protrude off of mooring lines at a ninety degree angle, 0:21:22.200 --> 0:21:25.280 so you imagine, you know, something kind of like zip 0:21:25.359 --> 0:21:30.040 ties or something like that, evenly spaced every foot or 0:21:30.080 --> 0:21:34.360 so down a mooring line, and they recommend having them 0:21:34.359 --> 0:21:37.640 go out around so there's like a little bar sticking 0:21:37.680 --> 0:21:39.960 off of the side of the rope going in a 0:21:40.000 --> 0:21:43.879 spiral around the rope all the way down, and the 0:21:44.000 --> 0:21:46.680 idea here is that it will make the rope more 0:21:46.800 --> 0:21:50.119 visible to wildlife, especially they say as you use it, 0:21:50.200 --> 0:21:54.080 more algae will attach to the ends of these cable ties, 0:21:54.400 --> 0:21:56.760 and it will make them even more visible. And of course, 0:21:56.800 --> 0:21:58.840 if the rays can see the mooring lines, they will 0:21:58.840 --> 0:22:01.000 avoid them. They're not going to run into them on purpose. 0:22:01.280 --> 0:22:03.800 Okay, So if I'm understanding the illustration you attacked here, 0:22:03.840 --> 0:22:08.959 it's like a spiral staircase of zip ties going up 0:22:08.960 --> 0:22:11.880 and down this particular line, and then, like you said, 0:22:11.880 --> 0:22:14.280 you'll end up with the stuff growing on those ties 0:22:14.320 --> 0:22:14.680 as well. 0:22:14.840 --> 0:22:16.800