WEBVTT - From the Vault: The Manta Ray, Part 2 0:00:06.240 --> 0:00:09.040 Hey, you welcome to Stuff to Blow your Mind. My 0:00:09.160 --> 0:00:11.440 name is Robert Lamb. Today's Saturday. So what do we 0:00:11.440 --> 0:00:13.920 have for you? It's gonna be The Manta Ray Part two. 0:00:14.520 --> 0:00:17.279 This is part two of three. It originally published seven eight, 0:00:17.480 --> 0:00:20.159 twenty twenty five. You know what a manta ray is, 0:00:20.200 --> 0:00:22.480 but now you're going to learn even more about them. 0:00:22.680 --> 0:00:23.520 Let's jump right in. 0:00:26.920 --> 0:00:30.680 Welcome to Stuff to Blow your Mind production of iHeartRadio. 0:00:36.600 --> 0:00:38.520 Hey you welcome to Stuff to Blow your Mind. 0:00:38.640 --> 0:00:41.480 My name is Robert Lamb and I am Joe McCormick, 0:00:41.520 --> 0:00:43.559 and we're back with part two in our series on 0:00:43.800 --> 0:00:48.400 manta rays and their close mobuld relatives. In the last 0:00:48.400 --> 0:00:51.440 episode of this series, we kicked things off by talking 0:00:51.479 --> 0:00:54.440 about an experience that you had rob recently where you 0:00:54.440 --> 0:00:57.800 and your family got to see reef manta rays in 0:00:57.840 --> 0:01:01.360 person while snorkeling in Indonesia, which sounds pretty amazing to 0:01:01.480 --> 0:01:02.920 get the details on that right. 0:01:02.960 --> 0:01:05.960 Correct, Yes, it was. It was amazing. You know, words 0:01:06.200 --> 0:01:07.280 can't quite describe it. 0:01:07.760 --> 0:01:10.760 Observing them, but not swimming quote with them. Weren't you 0:01:10.800 --> 0:01:11.920 weren't riding the rays? 0:01:12.080 --> 0:01:15.399 Correct, They were doing their own thing. We were trying 0:01:15.400 --> 0:01:19.880 to keep our distance. And observe from a distance, which 0:01:19.920 --> 0:01:21.480 is the correct way of going about things. 0:01:21.840 --> 0:01:24.000 So that was what inspired us to talk about manta 0:01:24.080 --> 0:01:26.199 rays in a series of episodes here on the show. 0:01:26.680 --> 0:01:30.440 In the last episode, we talked about the historical evolution 0:01:30.800 --> 0:01:34.680 of human attitudes toward manter rays with these old stories 0:01:34.720 --> 0:01:38.119 among some divers and sailors that cast manta rays as 0:01:38.240 --> 0:01:42.199 diabolical vampires of the sea. You know, there's one idea 0:01:42.240 --> 0:01:44.720 that they will like fold over a diver like a 0:01:44.760 --> 0:01:48.040 blanket of death. This, of course is not true, and 0:01:48.240 --> 0:01:51.440 since it seems like since roughly the nineteen seventies there 0:01:51.480 --> 0:01:55.400 has been more widespread recognition that mantas are gentle and 0:01:55.440 --> 0:01:58.640 not threatening to humans, though of course that has not 0:01:58.760 --> 0:02:01.400 stopped humans from threat them, and we talked about all 0:02:01.480 --> 0:02:04.880 kinds of ways that human activity can hurt these animals. 0:02:05.200 --> 0:02:08.480 These impacts range from accidental harms, like when mantas are 0:02:08.800 --> 0:02:11.800 killed as bycatch in commercial fishing. It's not what people 0:02:11.800 --> 0:02:13.919 are fishing for, but they just get caught in nets 0:02:13.919 --> 0:02:16.800 and other lines and other things, all the way to 0:02:17.000 --> 0:02:20.760 intentional targeting, where they are killed for their gill plates, 0:02:20.840 --> 0:02:26.040 which some people falsely allege to have medicinal powers, and 0:02:26.280 --> 0:02:30.000 in the vein of talking about tall tales of Mantas 0:02:30.040 --> 0:02:32.840 as vicious monsters, we also discussed a couple of movies 0:02:32.880 --> 0:02:35.799 made in the nineteen thirties that have a Killer Manta 0:02:35.880 --> 0:02:37.760 Ray or Devil Ray as the monster. 0:02:38.480 --> 0:02:40.959 I didn't mention this in that episode, but it's worth 0:02:41.080 --> 0:02:44.520 noting that, you, of course have one of Aquaman's arch 0:02:44.639 --> 0:02:48.040 enemies is Black Manta, so you know, it's the perfect 0:02:48.040 --> 0:02:51.080 mantle for a villain that was conceived. I believe in 0:02:51.080 --> 0:02:54.520 this era you also have Man Ray, which is a 0:02:54.639 --> 0:02:58.440 villain based on Black Manta that pops up on SpongeBob SquarePants, 0:02:58.680 --> 0:03:01.639 not to be confused with the the artist Man Ray. 0:03:02.040 --> 0:03:06.919 I think Black Manta is actually in the Aquaman movie 0:03:06.960 --> 0:03:08.760 with cal Drogo in it, isn't it. 0:03:08.960 --> 0:03:12.480 Oh yeah, yeah, who plays Black Manta? I don't I 0:03:12.480 --> 0:03:13.760 haven't seen any of those films. 0:03:13.800 --> 0:03:15.800 I don't remember any of the cast of that movie, 0:03:15.800 --> 0:03:18.960 except in Nicole Kidman in a really funny looking costume. 0:03:19.919 --> 0:03:22.600 So I you know, folks out there, No, I'm not 0:03:22.639 --> 0:03:25.760 the biggest superhero movie fan. I haven't kept up with 0:03:25.800 --> 0:03:28.720 all of the Marvel and DC superhero films, but I 0:03:28.800 --> 0:03:32.120 think I watched Aquaman on a plane for some reason. 0:03:32.680 --> 0:03:36.119 I remember thinking it was really funny, like highly amusing. 0:03:36.760 --> 0:03:39.560 Oh no, wait, I remember another cast member had Patrick 0:03:39.600 --> 0:03:42.360 Wilson like riding on a shark and saying, you will 0:03:42.440 --> 0:03:44.320 call me ocean master. 0:03:46.040 --> 0:03:48.120 I need to watch those on an airplane sometime. 0:03:48.240 --> 0:03:51.320 Yes, Jason Momoa, I'm sorry I called him cal Droco. 0:03:51.440 --> 0:03:54.040 That's not nice. His name is Jason Momoa. 0:03:54.480 --> 0:04:00.920 Suffice to say, however, the Western American slash European conceptions 0:04:00.960 --> 0:04:04.960 of the manta ray and related species have evolved since 0:04:05.720 --> 0:04:09.360 basically the nineteen seventies the nineteen seventies onward. Everyone has 0:04:09.560 --> 0:04:13.560 come to realize that manta rays are peaceful giants of 0:04:13.600 --> 0:04:16.080 the ocean and they are not out to eat. 0:04:15.920 --> 0:04:18.640 Us, right, And so we also talked about modern conservation 0:04:18.680 --> 0:04:22.200 efforts aimed at protecting mantas. You know, we got into 0:04:22.240 --> 0:04:24.640 like the cost benefit analysis that has to be done 0:04:24.680 --> 0:04:28.320 if you're considering building something like an ecological tourism trade 0:04:28.320 --> 0:04:31.600 around them. You know, there are risks but also potentially rewards. 0:04:32.800 --> 0:04:35.239 And we also talked about the basic biology of manta 0:04:35.320 --> 0:04:38.640 rays and their near relatives, their near relatives being the 0:04:38.680 --> 0:04:41.880 devil rays, mantas and devil rays together make up the 0:04:41.920 --> 0:04:46.799 genus Mobula, And we got into subjects including their body design, 0:04:47.000 --> 0:04:51.560 common feeding strategies, and leaping or breaching behavior where they 0:04:51.640 --> 0:04:53.479 jump out of the water and slap back down. We 0:04:53.520 --> 0:04:56.080 talked about some reasons they might do that, and we're 0:04:56.120 --> 0:04:57.400 back today to talk about more. 0:04:57.839 --> 0:05:01.320 Yeah, and we're gonna pick up in an interest. You're 0:05:01.320 --> 0:05:05.000 going to get into some more myths or potential myths 0:05:05.040 --> 0:05:08.159 about their behavior and what we may or may not 0:05:08.240 --> 0:05:09.240 know about those behaviors. 0:05:09.279 --> 0:05:12.440 Now right, well, I think this might be slightly different 0:05:12.440 --> 0:05:17.039 because it would be truths about their behavior with mythical interpretations, 0:05:17.320 --> 0:05:20.960 if that makes any sense. So in the last episode, 0:05:20.960 --> 0:05:23.919 we were talking about these incorrect folk beliefs about the 0:05:23.960 --> 0:05:26.160 man array. You know that they would attack boats or 0:05:26.200 --> 0:05:30.120 attack divers in the form of this underwater death blanket. 0:05:30.600 --> 0:05:33.600 And as a source there, I referenced an old article 0:05:33.680 --> 0:05:36.719 called the Story of the Devilfish from the ear Way 0:05:36.760 --> 0:05:40.080 back in the year nineteen ten by the American biologist 0:05:40.160 --> 0:05:43.120 Theodore gil There was another thread in this article that 0:05:43.160 --> 0:05:45.200 I found interesting and I wanted to come back to 0:05:45.240 --> 0:05:48.479 it today. So if you'll recall from last time in 0:05:48.560 --> 0:05:52.120 this article Gil, He's very dismissive of the belief that 0:05:52.160 --> 0:05:55.320 the manta tries to smother divers with its body or 0:05:55.360 --> 0:05:58.359 devour them with its gaping mouth. He points out that 0:05:58.400 --> 0:06:02.360 the manta is a filter feeder which eats tiny planktonic organisms. 0:06:02.560 --> 0:06:05.800 It does not eat large prey. There's no evidence of 0:06:05.800 --> 0:06:09.120 manta's targeting humans for violence, and they don't even have 0:06:09.160 --> 0:06:12.200 the right biological equipment to eat us if they were 0:06:12.240 --> 0:06:13.960 going to try to do that, which they're not going 0:06:14.040 --> 0:06:17.120 to try. But there is another part of the manta's 0:06:17.200 --> 0:06:21.560 more frightening reputation in pre modern times, which is the 0:06:21.600 --> 0:06:25.919 belief that mantas will attack boats, not divers, but boats, 0:06:26.000 --> 0:06:30.320 particularly the claim that a manta will drag a boat 0:06:30.520 --> 0:06:34.560 out to sea by the anchor line. So here I'm 0:06:34.560 --> 0:06:38.120 going to read a passage from Gill's article quote in 0:06:38.160 --> 0:06:41.200 one of the earliest notices of the devilfish by John 0:06:41.320 --> 0:06:46.320 Lawson in the History of Carolina seventeen fourteen. This peculiarity 0:06:46.360 --> 0:06:50.000 is described the devilfish, he says, has been known to 0:06:50.080 --> 0:06:53.080 weigh a ship's anchor and run with the vessel a 0:06:53.160 --> 0:06:56.120 league or two and bring her back against tide to 0:06:56.200 --> 0:06:59.560 almost the same place, but then the quote ends in 0:06:59.640 --> 0:07:02.359 guild on to say later notices do not give the 0:07:02.400 --> 0:07:06.640 animal credit for the same accommodating treatment, And he later 0:07:06.680 --> 0:07:10.080 alludes to these other accounts that tell of the devilfish 0:07:10.120 --> 0:07:13.680 pulling sailing boats around by the anchor to the wonder 0:07:13.720 --> 0:07:17.840 and fear of the sailors, and he also cites a 0:07:17.960 --> 0:07:20.280 more recent source to him at the time of his writing. 0:07:20.520 --> 0:07:24.680 This was a French naturalist named Leon de Guett describing 0:07:24.720 --> 0:07:28.000 the activity of pearl fishers in the Gulf of California 0:07:28.080 --> 0:07:32.320 in a text from eighteen ninety eight, and according to Deguet, 0:07:32.920 --> 0:07:36.440 when fishers are caught out at sea overnight in the 0:07:36.440 --> 0:07:40.960 Gulf of California, away from their usual mooring places, he 0:07:41.040 --> 0:07:45.080 says they will always drop two anchors, because they fear 0:07:45.120 --> 0:07:47.600 that if they only drop one, the anchor line will 0:07:47.640 --> 0:07:50.440 be seized by the devilfish in the dark, and thus 0:07:50.520 --> 0:07:53.120 the boat will be carried away into the open sea. 0:07:53.720 --> 0:07:57.040 And to get back to this up with his own observation, 0:07:57.320 --> 0:08:00.200 telling a story of how he was sent out to 0:08:00.400 --> 0:08:03.720 harpoon a specimen of a devil ray for the Natural 0:08:03.760 --> 0:08:08.360 History Museum of Paris, and he says, quote after one 0:08:08.400 --> 0:08:11.800 had been harpooned, it turned back on the boat, seized 0:08:11.840 --> 0:08:14.200 the bow with its head fins, and held it in 0:08:14.240 --> 0:08:18.560 its clasp till it was lanced the second time. So 0:08:18.640 --> 0:08:23.120 that's Deget's account, But Gil says even this direct observation 0:08:23.880 --> 0:08:26.640 does not really lend credence to the idea that mantas 0:08:26.720 --> 0:08:33.240 or devil rays deliberately attack, detain or hijack boats, because 0:08:33.360 --> 0:08:36.040 based on his own study, Gil writes that this kind 0:08:36.080 --> 0:08:39.679 of grasping with the headfins is automatic. He says, it's 0:08:39.720 --> 0:08:44.200 an involuntary muscular reaction when something is in front of 0:08:44.240 --> 0:08:47.440 the ray's mouth, so in this case it might happen 0:08:47.440 --> 0:08:50.800 to be the bow of the harpooner's boat, and so 0:08:50.960 --> 0:08:53.880 even when it's being attacked by somebody on the boat, 0:08:53.880 --> 0:08:56.199 when it's being harpooned, Gil argues that the ray was 0:08:56.240 --> 0:08:59.880 probably not actually trying to harm the boat, but rather 0:09:00.080 --> 0:09:02.880 is just being pulled toward the boat by the tension 0:09:02.880 --> 0:09:04.960 of the rope on the harpoon it had just been 0:09:05.080 --> 0:09:08.840 lanced with. And even to get himself the person originally 0:09:08.880 --> 0:09:11.600 telling the story of it seizing the bow of the boat, 0:09:12.000 --> 0:09:16.280 he says the devilfishes are generally timid, non aggressive animals. 0:09:17.000 --> 0:09:21.040 Though then, after saying this confusingly to get does seem open, 0:09:21.240 --> 0:09:24.480 he sort of opens up more claims of devilfish savagery 0:09:25.000 --> 0:09:28.679 and alleges that in the Gulf of California quote, numerous 0:09:28.720 --> 0:09:31.960 cases have occurred of death resulting to divers as well 0:09:32.040 --> 0:09:35.560 as bathers from encounters with the devilfish or manta as 0:09:35.600 --> 0:09:38.240 the men call it. On the other hand, the carcasses 0:09:38.280 --> 0:09:40.679 of many that are killed are used for bait for 0:09:40.800 --> 0:09:44.840 other fishes. The strange detail to include. 0:09:45.240 --> 0:09:48.760 Yeah, yeah, I mean all of this is the pardon 0:09:49.960 --> 0:09:52.000 the terminology here at fishy because. 0:09:51.800 --> 0:09:54.160 Dubious the third hand, Yeah. 0:09:53.920 --> 0:09:56.160 Yeah, I mean, because everything we know and have been 0:09:56.200 --> 0:09:59.880 discussing about rays, when they're threatened, they use a bir 0:10:00.120 --> 0:10:04.680 to speed they get away. That's their major way of 0:10:04.720 --> 0:10:07.680 defending themselves. So it doesn't really make sense based on 0:10:07.679 --> 0:10:09.560 what we know that they would turn around an attack 0:10:09.600 --> 0:10:13.200 of a ship or a boat, even if they are 0:10:13.240 --> 0:10:15.400 being acted upon with harpoons. 0:10:15.720 --> 0:10:18.240 Right, and as we discussed last time, of course, they 0:10:18.240 --> 0:10:22.040 are large animals, and any large animal could potentially hurt 0:10:22.040 --> 0:10:24.440 you just by bumping into you. Wrong, but there is 0:10:24.520 --> 0:10:28.079 really no evidence I could find of manta's being aggressive 0:10:28.080 --> 0:10:31.600 towards humans except for these like old third hand stories. 0:10:32.320 --> 0:10:32.680 Yeah. 0:10:32.720 --> 0:10:36.160 And I don't know if Gil gets into this or no, 0:10:36.200 --> 0:10:38.960 butical for one of the things with you get into 0:10:40.160 --> 0:10:44.160 oral histories of things like the devilfish the manta, you 0:10:44.240 --> 0:10:46.400 end up having to ask questions, well, is the manta 0:10:46.400 --> 0:10:49.160 in this story, even if there's a kernel of truth 0:10:49.200 --> 0:10:52.240 to it, is it indeed talking about the species that 0:10:52.280 --> 0:10:54.480 we are talking about as the manta ray, or is 0:10:54.480 --> 0:10:56.440 it referring to something else real or imagined. 0:10:56.640 --> 0:10:59.840 Yeah, so, even back in nineteen ten, Gill to me 0:11:00.000 --> 0:11:04.240 seems skeptical of these claims about it attacking boats. Certainly, 0:11:04.280 --> 0:11:08.240 modern researchers are skeptical of these stories of manterray aggression 0:11:08.240 --> 0:11:12.319 towards boats. But to the question of dragging boats, specifically 0:11:12.360 --> 0:11:15.959 by the anchor cable, is this just a tall tale 0:11:16.240 --> 0:11:19.640 like the mantray death blanket story or is there something 0:11:19.679 --> 0:11:22.040 more to that? Is there any modern evidence of things 0:11:22.080 --> 0:11:26.199 like this happening? The answer to this is yes. For example, 0:11:26.280 --> 0:11:30.080 I found a Reuter's article from February eleventh, nineteen ninety nine, 0:11:30.200 --> 0:11:33.960 called motor boat no match for manterray in Tug of War. 0:11:34.640 --> 0:11:38.760 Well, I generally, you know, I generally trust Reuters in 0:11:38.800 --> 0:11:42.840 their reporting, though usual usually I'm not reading about the 0:11:42.880 --> 0:11:46.240 marine biology. When I'm reading Reuters, usually it's a nice, 0:11:46.400 --> 0:11:51.120 you know, doom scroll into the abyss. So I missed 0:11:51.160 --> 0:11:52.760 this one when it came out. If I was in 0:11:52.760 --> 0:11:54.320 fact reading Routers at the time. 0:11:54.320 --> 0:11:56.240 I'll read from the beginning of the article and then 0:11:56.280 --> 0:11:58.240 summarize some other parts of it and we can make 0:11:58.320 --> 0:11:59.960 up our minds about it. Okay, what's going on here? 0:12:00.160 --> 0:12:04.240 So Dateline New Smurta Beach, Florida. Two Florida boaters met 0:12:04.240 --> 0:12:07.720 a real sea monster when their craft was dragged for 0:12:07.840 --> 0:12:10.320 hours by a powerful creature that turned out to be 0:12:10.400 --> 0:12:14.920 a giant manta ray, the Coastguard said Wednesday. Coastguard Petty 0:12:14.960 --> 0:12:18.400 Officer Scott Barnes said the agency received a radio distress 0:12:18.440 --> 0:12:21.440 call from a sixteen foot boat that reported it was 0:12:21.480 --> 0:12:25.200 being dragged by its anchor line by something unknown. The 0:12:25.240 --> 0:12:28.440 Coastguard sent a rescue boat to investigate and found the 0:12:28.440 --> 0:12:31.280 motor boat was being dragged in circles by something beneath 0:12:31.320 --> 0:12:34.440 the surface. The crew transferred the anchor line to the 0:12:34.480 --> 0:12:37.600 Coastguard vessel, freeing the men in the motor boat who 0:12:37.600 --> 0:12:40.200 had tried to use their ninety horsepower engine to go 0:12:40.280 --> 0:12:43.400 in reverse and stop themselves from being dragged out to sea. 0:12:44.200 --> 0:12:47.520 After the Coastguard's forty one foot boat pulled the anchor 0:12:47.559 --> 0:12:50.760 line for several minutes, a giant manta ray measuring an 0:12:50.880 --> 0:12:54.640 estimated eighteen feet in width, came to the surface, and 0:12:54.679 --> 0:12:57.000 then the article goes on to describe how the Coastguard 0:12:57.080 --> 0:13:00.400 struggled to pull the rope away. Eventually, the manta was 0:13:00.440 --> 0:13:03.720 able to disentangle itself from the rope and it swam 0:13:03.760 --> 0:13:06.360 away on its own, and by the end of the ordeal, 0:13:07.080 --> 0:13:09.520 the manta, they estimate, had pulled the boat for almost 0:13:09.559 --> 0:13:12.160 two hours, taking it about a mile and a half 0:13:12.240 --> 0:13:16.400 away from shore. But you could easily get the wrong 0:13:16.440 --> 0:13:20.200 idea about this, thinking that it supports this old notion 0:13:20.320 --> 0:13:24.240 that mantas will attack boats, that they are doing this 0:13:24.520 --> 0:13:28.200 on purpose, they're trying to drag the sailors out to sea, 0:13:28.280 --> 0:13:31.160 out to their deaths or something. From what I've read, 0:13:31.240 --> 0:13:34.600 there is absolutely zero evidence to support the idea that 0:13:34.679 --> 0:13:37.400 the mantas are acting aggressively when they pull a boat 0:13:37.440 --> 0:13:41.240 by the anchor line. The zero evidence that they're acting 0:13:41.240 --> 0:13:45.760 aggressively or even acting intentionally. Rather, this is almost certainly 0:13:45.800 --> 0:13:49.520 a case of manta's getting stuck. They are getting tangled 0:13:49.640 --> 0:13:54.280 in underwater ropes and chains by accident and then pulling 0:13:54.280 --> 0:13:57.800 the boat because they are unable to free themselves. And 0:13:57.880 --> 0:13:59.800 when you look at their heads, you look up a 0:13:59.840 --> 0:14:02.679 picture of a manta ray or a devil ray, you 0:14:02.720 --> 0:14:05.480 can see how this might easily happen. They almost have 0:14:05.600 --> 0:14:09.160 biological mooring cleats with their cephalic fins. 0:14:09.480 --> 0:14:21.640 Yeah, yeah, you can imagine them, you know, catching the line. 0:14:22.040 --> 0:14:25.040 For one more example of a modern encounter, I found 0:14:25.040 --> 0:14:28.320 a video on YouTube that the title begins with Giant 0:14:28.360 --> 0:14:32.640 manta ray tangled in anchorchain, forty miles off shore. This 0:14:32.720 --> 0:14:35.320 is a video of some people out in a fishing 0:14:35.360 --> 0:14:38.480 boat in the Gulf of Mexico and a manta does 0:14:38.600 --> 0:14:41.440 get caught in their anchor line. Like it looks when 0:14:41.440 --> 0:14:44.080 you can see it, it looks like the line is not 0:14:44.160 --> 0:14:46.960 just caught between the cephalic fins, but kind of wrapped 0:14:47.080 --> 0:14:50.560 around them, like the lobes on its head have the 0:14:50.560 --> 0:14:54.680 line going across as well as between, and you can 0:14:54.680 --> 0:14:57.920 see it struggling. At a couple of points in this video. 0:14:58.280 --> 0:15:01.560 It quite strangely, it almost seems to be coming up 0:15:01.600 --> 0:15:04.320 to the surface and holding still while the fishermen are 0:15:04.320 --> 0:15:07.120 trying to get it untangled. Then weirdly kind of matches. 0:15:07.160 --> 0:15:09.320 But then I don't know how to interpret what I'm 0:15:09.320 --> 0:15:11.480 seeing there, so maybe it shouldn't be taken this way. 0:15:11.800 --> 0:15:13.840 But it kind of reminds me of all these stories 0:15:14.240 --> 0:15:17.600 people talk about of manta rays being very like, kind 0:15:17.640 --> 0:15:20.080 of slow moving and gentle while they come up to 0:15:20.120 --> 0:15:23.000 them and almost kind of letting people, you know, interact 0:15:23.040 --> 0:15:25.720 with them. Again, not encouraging people to do that unless 0:15:25.720 --> 0:15:28.000 you're trying to free one from a problem you've created. 0:15:28.560 --> 0:15:30.200 But anyway, in the end here the people in the 0:15:30.200 --> 0:15:33.840 boat are able to succeed by they sever the line 0:15:33.880 --> 0:15:37.120 in one place and that allows them to get it 0:15:37.200 --> 0:15:40.360 unwrapped from around the manta and they let the manta 0:15:40.400 --> 0:15:42.480 swim away. So it seems like the manta gets away 0:15:42.520 --> 0:15:45.080 in the end of this, which is heartwarming. In fact, 0:15:45.160 --> 0:15:47.360 all these like bro fishermen are like high five in 0:15:47.400 --> 0:15:50.920 each other. They're like, yeah, we did it. 0:15:50.920 --> 0:15:51.440 It's sweet. 0:15:51.720 --> 0:15:54.440 But once again seems like a quite clear case of 0:15:54.480 --> 0:15:57.440 like the manta is not doing this on purpose. It's 0:15:57.520 --> 0:15:59.560 not out here today. Thing say, and I'd like to 0:15:59.640 --> 0:16:02.440 drag a boat around it ended up in this situation 0:16:02.560 --> 0:16:03.480 against its will. 0:16:03.920 --> 0:16:04.160 Yeah. 0:16:04.240 --> 0:16:08.280 Yeah, Like you said, the cephalic fins are kind of 0:16:08.280 --> 0:16:11.960 look like natural line catchers. And then they're also just 0:16:12.040 --> 0:16:15.280 quite I mean, they're they're wing shaped, they're they're they're 0:16:15.320 --> 0:16:18.640 quite wide. We've talked about their their wingspans, and yeah, 0:16:18.640 --> 0:16:21.520 that's just more real estate to potentially run into a line. 0:16:21.640 --> 0:16:24.720 Yeah. And so Gil talks about this in his article 0:16:24.840 --> 0:16:28.440 and says that these the cephalic fins or cephalic lobes 0:16:28.480 --> 0:16:30.600 the kind of horns of the devilfish. 0:16:31.080 --> 0:16:31.320 Uh. 0:16:31.440 --> 0:16:34.960 They they're like an elephant's trunk. He quotes another author 0:16:35.040 --> 0:16:37.880 saying that then they can kind of grasp objects and 0:16:37.920 --> 0:16:41.040 pull them in. He says they tend to rapidly kind 0:16:41.040 --> 0:16:44.600 of close in around the mouth when something appears in 0:16:44.640 --> 0:16:48.480 front of the mouth and uh, and that the the 0:16:49.000 --> 0:16:52.680 fish will have a kind of obstinacy in, you know, 0:16:52.800 --> 0:16:56.440 refusing to release things that go in like that. Gil 0:16:56.520 --> 0:16:59.560 says quote that these arms are muscular and powerful has 0:16:59.600 --> 0:17:03.000 been dim on many occasions. The natural movement of the 0:17:03.040 --> 0:17:06.880 head fins or corropteries is inward and when any object 0:17:06.920 --> 0:17:10.600 strikes between them, it is instinctively held a proceeding which 0:17:10.640 --> 0:17:14.280 explains the undoubted fact that these fishes can run away 0:17:14.320 --> 0:17:19.040 with quite large vessels. So Gill's chalking this up to 0:17:19.760 --> 0:17:23.679 involuntary motion of the strong cephalic fins closing over things 0:17:23.680 --> 0:17:26.080 that hit in the front of the mouth, which occasionally, 0:17:26.320 --> 0:17:30.160 in some unlucky circumstances, just happens to be an anchor line. 0:17:31.280 --> 0:17:35.000 I think Gil is absolutely correct that these boat dragging 0:17:35.040 --> 0:17:38.240 incidents are not aggressive or intentional on the part of 0:17:38.280 --> 0:17:41.280 the ray, but is he correct about the mechanism. I 0:17:41.320 --> 0:17:44.199 was looking for modern sources and couldn't really find anything 0:17:44.240 --> 0:17:48.800 to confirm or deny his ideas there about the specific 0:17:48.920 --> 0:17:53.520 motion of the cephalic fins being involved. But I did 0:17:53.600 --> 0:17:58.560 find some commentary from more recent marine biology resources, specifically 0:17:58.800 --> 0:18:01.800 something from the organization known as the Manta Trust, which 0:18:01.800 --> 0:18:06.720 has a page on the subject of manta mooring line entanglements, 0:18:07.119 --> 0:18:11.560 and they highlight some different biological facts which make mooring 0:18:11.640 --> 0:18:16.800 line entanglements common for manta rays. Manta rays, like their 0:18:16.880 --> 0:18:23.080 cousins sharks, and also like tuna, are obligate ram ventilators, 0:18:23.320 --> 0:18:28.480 meaning they do not have the biological equipment needed to 0:18:28.800 --> 0:18:32.719 pump water over their gills when their bodies are at rest. 0:18:33.240 --> 0:18:35.920 So in order to make water flow over their gills 0:18:36.040 --> 0:18:38.679 so they can extract oxygen from the water and breathe, 0:18:39.000 --> 0:18:42.240 they have to move their bodies. So you've probably heard 0:18:42.280 --> 0:18:44.840 before that if a shark is forced to hold still, 0:18:45.000 --> 0:18:47.840 it will die. It has to swim to breathe. That 0:18:48.000 --> 0:18:51.000 is essentially true, and it's true for mantas as well. 0:18:51.920 --> 0:18:54.200 Fish that don't have to keep moving to breathe have 0:18:54.280 --> 0:18:57.360 what's known as a buckle pump system, where you use 0:18:57.520 --> 0:19:00.960 muscles around your mouth and throat to hump fresh water 0:19:01.160 --> 0:19:04.240 over the gills. Mantas don't have that. They've got to swim. 0:19:04.359 --> 0:19:06.000 Now, I do want to point out that Joe said 0:19:06.119 --> 0:19:10.199 essentially true of sharks, so's we can get into a 0:19:10.200 --> 0:19:13.399 deeper discussion maybe in another episode where we talk about 0:19:13.560 --> 0:19:17.679 the different behaviors of different types of sharks. You do 0:19:17.760 --> 0:19:20.199 have some shark varieties that live in close to the 0:19:20.240 --> 0:19:22.760 reef that are going to be that can be still 0:19:22.800 --> 0:19:23.920 for extended periods of time. 0:19:24.000 --> 0:19:27.600 Yeah, they might actually have the buckle pumping equipment. But yeah, 0:19:27.640 --> 0:19:32.240 like great white sharks, for example, don't they're ram ventilators. 0:19:32.000 --> 0:19:35.520 Exact Yes, absolutely true of great whites, but. 0:19:35.520 --> 0:19:38.080 Anyway certainly true of manta rays. They have to swim 0:19:38.119 --> 0:19:41.480 in order to breathe. They are also ram ventilators, and 0:19:41.520 --> 0:19:44.200 so this means that getting entangled in a line can 0:19:44.280 --> 0:19:46.800 be deadly to a manta. If it is stuck and 0:19:46.840 --> 0:19:50.640 it can't swim around, it can't really breathe. And this 0:19:50.720 --> 0:19:54.680 might also explain why a manta would keep swimming even 0:19:54.720 --> 0:19:57.360 when it has a boat dragging behind it. It kind 0:19:57.359 --> 0:19:59.880 of has to swim. Pair of this with a couple 0:20:00.040 --> 0:20:05.240 of other biological facts. Mantas can't swim backwards. They are 0:20:05.520 --> 0:20:08.640 highly maneuverable fish in a way. They can turn around 0:20:08.680 --> 0:20:10.440 and you see them in the water doing these beautiful 0:20:10.480 --> 0:20:15.560 summersaults and everything, but it's always with forward motion, which 0:20:15.800 --> 0:20:19.480 usually means that the line just gets even more tangled 0:20:19.560 --> 0:20:22.320 up on them as they twist and somer salt around 0:20:22.960 --> 0:20:25.280 and they would need to really be able to back 0:20:25.400 --> 0:20:27.680 up to release the line, but they can't back up. 0:20:28.720 --> 0:20:29.240 Great point. 0:20:29.680 --> 0:20:32.240 The other thing is that the manta trust says is 0:20:32.320 --> 0:20:35.520 they are often not able to see the thin line 0:20:35.560 --> 0:20:37.919 of a rope or a chain when it's directly in 0:20:37.960 --> 0:20:40.919 front of them. And so you put all this together 0:20:41.440 --> 0:20:44.480 and it easily explains how mantas can get tangled in 0:20:44.600 --> 0:20:48.040 mooring lines and can end up pulling whatever these lines 0:20:48.080 --> 0:20:51.440 are attached to. This is usually not threatening to humans, 0:20:51.440 --> 0:20:54.320 but it is very threatening to the ray. Rays often 0:20:54.320 --> 0:20:57.760 asphyxiate and die when they get caught in moorings. And 0:20:57.840 --> 0:21:00.360 so the Manta Trust has this document where they make 0:21:00.440 --> 0:21:03.879 recommendations for making mooring lines safer for mantas. You can 0:21:03.920 --> 0:21:06.480 actually look this document up on their website for the 0:21:06.560 --> 0:21:10.880 full recommendations, but they suggest a few measures, like one 0:21:10.960 --> 0:21:15.920 just reducing the presence of especially loose line in the water. 0:21:16.119 --> 0:21:19.040 Loose or slack lines are more dangerous to raise than 0:21:19.119 --> 0:21:22.639 tight lines. You can probably kind of imagine where they are, Like, 0:21:22.680 --> 0:21:25.160 a looser line is easier to get fully just tangled 0:21:25.240 --> 0:21:27.720 up in, whereas a taut line, you know, you might 0:21:27.920 --> 0:21:32.240 more likely bump into and then something can get yeah. Yeah. 0:21:32.240 --> 0:21:36.280 But then also they recommend this interesting system that I 0:21:36.320 --> 0:21:37.600 don't know if I would have thought of this, but 0:21:37.640 --> 0:21:43.040 this is cool. They recommend attaching cable ties that protrude 0:21:43.240 --> 0:21:46.159 off of mooring lines at a ninety degree angle. So 0:21:46.240 --> 0:21:49.560 you imagine, you know, something kind of like zip ties 0:21:49.680 --> 0:21:54.160 or something like that, evenly spaced every foot or so 0:21:54.680 --> 0:21:58.359 down a mooring line, and they recommend having them go 0:21:58.560 --> 0:22:01.960 out around. So there's a little bar sticking off of 0:22:02.040 --> 0:22:05.000 the side of the rope going in a spiral around 0:22:05.040 --> 0:22:08.600 the rope all the way down. And the idea here 0:22:08.760 --> 0:22:11.840 is that it will make the rope more visible to wildlife, 0:22:11.960 --> 0:22:15.320 especially they say as you use it, more algae will 0:22:15.320 --> 0:22:18.520 attach to the ends of these cable ties, and it 0:22:18.520 --> 0:22:20.840 will make them even more visible. And of course, if 0:22:20.840 --> 0:22:22.640 the rays can see the mooring lines, they. 0:22:22.600 --> 0:22:23.239