1 00:00:01,840 --> 00:00:07,520 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff. 2 00:00:07,600 --> 00:00:12,440 Speaker 1: Lauren Vogelbaum. Here today we're talking about axe lottles, a 3 00:00:12,560 --> 00:00:15,760 Speaker 1: threatened species of large salamander that live in fresh water, 4 00:00:16,200 --> 00:00:19,400 Speaker 1: and they're not actually fish at all. Despite sometimes being 5 00:00:19,440 --> 00:00:23,680 Speaker 1: called Mexican walking fish. With their round heads and permanently 6 00:00:23,680 --> 00:00:27,600 Speaker 1: smiling faces, wild axe lottles are cute. It's one of 7 00:00:27,640 --> 00:00:29,479 Speaker 1: the reasons they do well with pet owners in the 8 00:00:29,480 --> 00:00:33,840 Speaker 1: pet trade. One reason they're cute is because they display niatny, 9 00:00:34,200 --> 00:00:36,760 Speaker 1: which means they retain a lot of their juvenile features 10 00:00:36,800 --> 00:00:42,200 Speaker 1: throughout their adult life, beyond their faces. Although adult axe 11 00:00:42,200 --> 00:00:45,920 Speaker 1: lottles also have functional lungs like other salamander species and 12 00:00:46,120 --> 00:00:49,599 Speaker 1: can breathe through their skin, they also have big, fluffy, 13 00:00:49,800 --> 00:00:54,920 Speaker 1: feathery external gills, something most amphibians don't keep after babyhood. 14 00:00:56,040 --> 00:00:59,280 Speaker 1: They have small, delicate, webbed feet and a long tadpole 15 00:00:59,360 --> 00:01:02,720 Speaker 1: like tail crusted with a translucent fin. Because they don't 16 00:01:02,760 --> 00:01:04,520 Speaker 1: have to rely on their webbed feet and legs for 17 00:01:04,600 --> 00:01:07,040 Speaker 1: land travel, but they do have to be able to 18 00:01:07,080 --> 00:01:10,679 Speaker 1: move through water like a big tadpole. In the wild, 19 00:01:10,720 --> 00:01:14,000 Speaker 1: they're most often dark brown, gray or black, with lighter speckles, 20 00:01:14,440 --> 00:01:17,960 Speaker 1: but deepigmented variants with gold skin and eyes or pink 21 00:01:17,959 --> 00:01:20,600 Speaker 1: skin and red gills are common, and you often see 22 00:01:20,600 --> 00:01:25,000 Speaker 1: them as pets as scientists think that they stay baby 23 00:01:25,120 --> 00:01:28,920 Speaker 1: like throughout their lifespans because, unlike other salamondar species, the 24 00:01:28,920 --> 00:01:33,679 Speaker 1: wild ax lottl population evolved in very stable habitats. In 25 00:01:33,760 --> 00:01:37,400 Speaker 1: most other salamonder species, such as the tiger salamander, live 26 00:01:37,440 --> 00:01:40,199 Speaker 1: in wetlands that dry up during certain parts of the year, 27 00:01:40,800 --> 00:01:43,000 Speaker 1: so they have to get rid of their feathery gills 28 00:01:43,080 --> 00:01:46,600 Speaker 1: and breathe through functional lungs and through their skin. A 29 00:01:46,680 --> 00:01:49,520 Speaker 1: wild ax lottles evolved in a habitat with year round 30 00:01:49,560 --> 00:01:53,000 Speaker 1: water and with very few aquatic predators, so they don't 31 00:01:53,000 --> 00:01:55,800 Speaker 1: need to spend energy changing their bodies to suit their 32 00:01:55,920 --> 00:02:01,080 Speaker 1: changing circumstances. An x lottle's life span is about fifteen 33 00:02:01,160 --> 00:02:04,120 Speaker 1: years in captivity, but a wild x lottle probably lives 34 00:02:04,120 --> 00:02:07,360 Speaker 1: only five or six years. They reach sexual maturity at 35 00:02:07,400 --> 00:02:10,080 Speaker 1: one year, and though they are solitary creatures for the 36 00:02:10,080 --> 00:02:13,839 Speaker 1: most part, in February, breeding season begins and wild ax 37 00:02:13,880 --> 00:02:18,280 Speaker 1: lottle males begin finding females using pheromones. When they get together, 38 00:02:18,480 --> 00:02:20,639 Speaker 1: he does a courtship dance in which he shakes his 39 00:02:20,720 --> 00:02:24,559 Speaker 1: tail in her direction. After the female acquiesces to his attentions, 40 00:02:24,680 --> 00:02:27,040 Speaker 1: she pokes him with her nose and he deposits a 41 00:02:27,080 --> 00:02:29,560 Speaker 1: sperm packet on the lake floor, which he picks up 42 00:02:29,600 --> 00:02:33,799 Speaker 1: and uses to fertilize her eggs. The wild, female ex 43 00:02:33,880 --> 00:02:36,240 Speaker 1: lottle will lay hundreds of eggs in the weeds or 44 00:02:36,400 --> 00:02:39,440 Speaker 1: around some rocks, and then leave them to fen for themselves. 45 00:02:39,960 --> 00:02:44,160 Speaker 1: Baby x lottles receive zero parental care. In fact, young 46 00:02:44,160 --> 00:02:47,280 Speaker 1: axe lottels, hungry after hatching from their eggs, have been 47 00:02:47,280 --> 00:02:50,280 Speaker 1: observed gnawing on their siblings legs and pails for sustenance, 48 00:02:51,240 --> 00:02:53,959 Speaker 1: though as you'll see, this is totally fine because the 49 00:02:54,040 --> 00:02:59,480 Speaker 1: legs will just grow back in their home ecosystem. Axe 50 00:02:59,520 --> 00:03:02,520 Speaker 1: lottles are or at least used to be top predators 51 00:03:02,600 --> 00:03:06,000 Speaker 1: around the lakes, wetlands, and canals of Central Mexico, where 52 00:03:06,000 --> 00:03:10,720 Speaker 1: they originated and once thrived. Although they appear unassuming, they're 53 00:03:10,800 --> 00:03:16,240 Speaker 1: actually ruthless carnivores, feasting on worms, mollusks, insects and insect larvae, 54 00:03:16,400 --> 00:03:19,440 Speaker 1: and even small fish. In the wild, they'll also eat 55 00:03:19,520 --> 00:03:21,400 Speaker 1: pretty much any animal that you put in a tank 56 00:03:21,440 --> 00:03:26,240 Speaker 1: with them. Post ancient Mesoamerican cultures used the axe lottle 57 00:03:26,320 --> 00:03:29,320 Speaker 1: as a source of food and medicine, Some said a 58 00:03:29,360 --> 00:03:32,799 Speaker 1: gift from the gods. A Myths from that area associate 59 00:03:32,840 --> 00:03:36,040 Speaker 1: the animal with an underworld god, Sholat, who in some 60 00:03:36,200 --> 00:03:40,240 Speaker 1: legends escapes capture by turning himself into a small, feathery amphibian. 61 00:03:41,320 --> 00:03:44,160 Speaker 1: His name comes from the Nawat language and is spelled 62 00:03:44,160 --> 00:03:46,320 Speaker 1: the same as axe lottle without the letter A at 63 00:03:46,320 --> 00:03:49,480 Speaker 1: the front, but European language speakers didn't pick up the 64 00:03:49,480 --> 00:03:53,840 Speaker 1: pronunciation when they picked up the animal. A part of 65 00:03:53,840 --> 00:03:56,600 Speaker 1: the mythology of the axe lottl centers around the fact that, 66 00:03:56,800 --> 00:04:00,720 Speaker 1: alike a powerful god, they are difficult to kill. If 67 00:04:00,720 --> 00:04:03,560 Speaker 1: an ox lottl loses virtually any part of its body, 68 00:04:03,600 --> 00:04:07,520 Speaker 1: it can regenerate it no problem a. While sub lizards 69 00:04:07,560 --> 00:04:11,240 Speaker 1: can grow back a tail bisected, flatworms can grow back 70 00:04:11,280 --> 00:04:14,400 Speaker 1: the other half, and starfish can regrow a limb, an 71 00:04:14,440 --> 00:04:17,400 Speaker 1: ax lottle can regrow practically any part of its body 72 00:04:17,480 --> 00:04:21,080 Speaker 1: in a few weeks. For the article this episode is 73 00:04:21,120 --> 00:04:23,719 Speaker 1: based on How Stuff Works. Spoke with David Gardner, a 74 00:04:23,760 --> 00:04:26,520 Speaker 1: professor in the school of Biological Sciences at the University 75 00:04:26,520 --> 00:04:30,920 Speaker 1: of California, Irvine. Back in twenty nineteen, he said, of 76 00:04:30,960 --> 00:04:34,320 Speaker 1: the animals that are closest to us the vertebrates, salamanders 77 00:04:34,360 --> 00:04:36,760 Speaker 1: are the only ones that can regenerate in this way 78 00:04:37,080 --> 00:04:41,120 Speaker 1: and can heal without scars. Other salamanders can regenerate, but 79 00:04:41,240 --> 00:04:46,360 Speaker 1: axe lottls do it best. When the Europeans got wind 80 00:04:46,400 --> 00:04:49,480 Speaker 1: of axe lottal regeneration, ax lottls went from being a 81 00:04:49,640 --> 00:04:52,000 Speaker 1: sort of boring exhibit in a zoo to one of 82 00:04:52,000 --> 00:04:55,640 Speaker 1: the most important and longest self sustaining lab animals in history. 83 00:04:56,800 --> 00:04:59,839 Speaker 1: Among the first modern zoo animals, thirty four ax lottls 84 00:05:00,040 --> 00:05:02,520 Speaker 1: are brought from Mexico, along with three deer and three 85 00:05:02,520 --> 00:05:06,680 Speaker 1: wild dogs, to Paris in eighteen sixty four, and although 86 00:05:06,680 --> 00:05:10,440 Speaker 1: they weren't as interesting to nineteenth century zoogoers as the larger, 87 00:05:10,560 --> 00:05:15,320 Speaker 1: more charismatic animals, scientists quickly realized that these unassuming little 88 00:05:15,320 --> 00:05:19,600 Speaker 1: guys were strange, almost mythological in fact, and they were 89 00:05:19,600 --> 00:05:22,400 Speaker 1: studied at the time for their unusual adult form and 90 00:05:22,440 --> 00:05:27,880 Speaker 1: their regenerative abilities. A Gardner said, these days, ax lottls 91 00:05:27,920 --> 00:05:31,280 Speaker 1: are hugely important model systems for our studies about regeneration. 92 00:05:32,080 --> 00:05:35,480 Speaker 1: We've known for decades, centuries even that we can remove 93 00:05:35,520 --> 00:05:38,280 Speaker 1: parts of a developing embryonic structure and the cells that 94 00:05:38,320 --> 00:05:41,919 Speaker 1: are left behind will fill in, repair and regenerate that structure. 95 00:05:42,960 --> 00:05:46,080 Speaker 1: But in most animals mammals, for instance, the system sort 96 00:05:46,080 --> 00:05:49,440 Speaker 1: of shuts down at the end of embryonic development. Axe 97 00:05:49,520 --> 00:05:52,160 Speaker 1: Lottels and other salamanders seem to be able to revert 98 00:05:52,200 --> 00:05:56,400 Speaker 1: back to that embryonic like state, reaccessing the developmental program 99 00:05:56,440 --> 00:06:00,560 Speaker 1: that's already there. Humans have the program, we just stop 100 00:06:00,640 --> 00:06:03,279 Speaker 1: being able to access it when we're no longer an embryo. 101 00:06:04,400 --> 00:06:07,320 Speaker 1: You could say, we, like axe lottels, have evolved the 102 00:06:07,360 --> 00:06:10,760 Speaker 1: ability to regenerate just fine, but we've also evolved a 103 00:06:10,800 --> 00:06:16,840 Speaker 1: mechanism that inhibits that. Scientists hope to figure out how 104 00:06:16,839 --> 00:06:19,839 Speaker 1: to one day apply the axe lottl's regeneration abilities to 105 00:06:19,880 --> 00:06:24,320 Speaker 1: the human body. They can regenerate new limbs, heart tissue, eyes, 106 00:06:24,360 --> 00:06:26,679 Speaker 1: and even its spinal cord in parts of their brain, 107 00:06:27,160 --> 00:06:30,400 Speaker 1: and make new neurons throughout their lives, which human brains 108 00:06:30,440 --> 00:06:35,039 Speaker 1: do too, though not as readily. It is possible to 109 00:06:35,120 --> 00:06:38,960 Speaker 1: force anax lottel to metamorphin into an adult salamander without 110 00:06:39,000 --> 00:06:42,720 Speaker 1: gills by injecting it with iodine or thyroxine, or by 111 00:06:42,760 --> 00:06:46,440 Speaker 1: feeding it foods that are rich in iodine. However, scientists 112 00:06:46,440 --> 00:06:52,400 Speaker 1: have found that afterward they don't easily regenerate cells, and 113 00:06:52,720 --> 00:06:55,880 Speaker 1: for all their seeming magic, wild ax lottls are critically 114 00:06:55,960 --> 00:06:59,760 Speaker 1: endangered today. The waterways in their home around Mexico City 115 00:06:59,839 --> 00:07:03,560 Speaker 1: have become not only polluted by aging wastewater systems, but 116 00:07:03,760 --> 00:07:07,520 Speaker 1: overrun by introduced telapia and perch, both of which view 117 00:07:07,560 --> 00:07:11,440 Speaker 1: ax lottles as a delicious snack. In twenty nineteen, a 118 00:07:11,520 --> 00:07:14,600 Speaker 1: population assessment concluded that there are probably fewer than one 119 00:07:14,640 --> 00:07:19,760 Speaker 1: thousand individuals left in the wild. The Mexican government and 120 00:07:19,880 --> 00:07:22,440 Speaker 1: many conservation groups are doing their best to save the 121 00:07:22,480 --> 00:07:25,640 Speaker 1: species by restoring the lakes and natural habitats they live in. 122 00:07:26,800 --> 00:07:30,480 Speaker 1: One strategy is to make stationary floating island habitats for them, 123 00:07:30,840 --> 00:07:35,679 Speaker 1: called danumpas a Spanish word for rafts made of aquatic vegetation, mud, 124 00:07:35,720 --> 00:07:38,360 Speaker 1: and wood that were used hundreds of years ago as 125 00:07:38,400 --> 00:07:43,920 Speaker 1: floating gardens before Spanish colonizers arrived. When what's now part 126 00:07:43,920 --> 00:07:46,840 Speaker 1: of Mexico City was the Triple Alliance City, state of 127 00:07:46,920 --> 00:07:50,760 Speaker 1: tinoche Titlan. The Empire built and farmed on a vast 128 00:07:50,760 --> 00:07:54,880 Speaker 1: network of chanampas for miles around the city. This system 129 00:07:54,920 --> 00:07:58,720 Speaker 1: of agriculture created canals that were shallow and sheltered, and 130 00:07:58,800 --> 00:08:02,800 Speaker 1: where the ox lottl popular thrived. When the Spanish conquered 131 00:08:02,840 --> 00:08:05,880 Speaker 1: the city, they remove the chumpus and drained the canals 132 00:08:05,880 --> 00:08:11,120 Speaker 1: and lakes. Today, the natural habitat of the wild oxilotl 133 00:08:11,120 --> 00:08:14,160 Speaker 1: population is limited to the southern part of Mexico City. 134 00:08:15,080 --> 00:08:17,920 Speaker 1: People are working to remove the invasive fishes that eat 135 00:08:17,920 --> 00:08:21,400 Speaker 1: the axe lottls and begin using jenumpus again, which not 136 00:08:21,440 --> 00:08:24,720 Speaker 1: only provides habitat for the axe lottles, it also filters 137 00:08:24,760 --> 00:08:29,080 Speaker 1: toxins out of the lake water. Ecotourism of these danumpus 138 00:08:29,200 --> 00:08:35,079 Speaker 1: has assisted in funding axe loottal conservation efforts. Meanwhile, captive 139 00:08:35,080 --> 00:08:38,760 Speaker 1: populations axe lottls are doing great. They're the most widely 140 00:08:38,800 --> 00:08:43,480 Speaker 1: distributed amphibian in the world, and because scientists desperately want 141 00:08:43,520 --> 00:08:45,439 Speaker 1: to figure out how to help you regenerate a new 142 00:08:45,480 --> 00:08:48,240 Speaker 1: set of toes, millions of them live in labs around 143 00:08:48,240 --> 00:08:52,080 Speaker 1: the globe. And while axe lottle research is important in 144 00:08:52,160 --> 00:08:56,080 Speaker 1: science and captive populations of pet axe lottls are also popular. 145 00:08:58,440 --> 00:09:01,760 Speaker 1: It's not legal everywhere for pet owners to keep ax lottles, 146 00:09:02,000 --> 00:09:04,480 Speaker 1: so it's important to check your local exotic pet laws 147 00:09:04,520 --> 00:09:07,880 Speaker 1: before you go looking for one and mess with any 148 00:09:07,920 --> 00:09:10,080 Speaker 1: living creature. Be sure to read up on how to 149 00:09:10,120 --> 00:09:13,120 Speaker 1: care for one before you take the dive. No pun intended. 150 00:09:13,640 --> 00:09:16,920 Speaker 1: They're not difficult to keep per se, but speaking as 151 00:09:17,000 --> 00:09:20,360 Speaker 1: a home aquarium enthusiast myself, I can tell you that 152 00:09:20,480 --> 00:09:23,880 Speaker 1: keeping any aquatic life form comfortable in your non aquatic 153 00:09:23,880 --> 00:09:31,800 Speaker 1: home can take a lot of work. Today's episode is 154 00:09:31,840 --> 00:09:34,199 Speaker 1: based on the article the super cute axe Lottle is 155 00:09:34,240 --> 00:09:38,160 Speaker 1: also a ruthless carnivore on HowStuffWorks dot Com, written by Jesslinshields. 156 00:09:38,600 --> 00:09:41,160 Speaker 1: Brain Stuff is production of iHeartRadio in partnership with how 157 00:09:41,160 --> 00:09:44,320 Speaker 1: stuffworks dot Com and is produced by Tyler Klang. Perform 158 00:09:44,320 --> 00:09:47,160 Speaker 1: more podcasts from my heart Radio, visit the iHeartRadio app, 159 00:09:47,280 --> 00:10:00,920 Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.