1 00:00:02,040 --> 00:00:07,200 Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, 2 00:00:07,240 --> 00:00:10,680 Speaker 1: Lauren Vogelbaum. Here. If you live in North America, you've 3 00:00:10,680 --> 00:00:14,560 Speaker 1: probably seen a Virginia a possum classification to Delphis Virginiana. 4 00:00:15,280 --> 00:00:18,160 Speaker 1: Maybe the unfortunate creature was dead on the road, or 5 00:00:18,200 --> 00:00:20,360 Speaker 1: maybe it was very much alive on your porch eating 6 00:00:20,360 --> 00:00:22,720 Speaker 1: garbage in the middle of the night. But in either 7 00:00:22,800 --> 00:00:26,560 Speaker 1: case you might have thought, oh, gross, a possum. But 8 00:00:26,880 --> 00:00:30,360 Speaker 1: you would have been off base on several counts. First 9 00:00:30,360 --> 00:00:34,080 Speaker 1: of all, possums live in Australia and are also a marsupial, 10 00:00:34,120 --> 00:00:36,120 Speaker 1: which means they raise their young in a pouch like 11 00:00:36,159 --> 00:00:39,040 Speaker 1: a kangaroo, but they are a completely different species. And 12 00:00:39,080 --> 00:00:41,560 Speaker 1: the animal currently snuggling with a half eaten bag of 13 00:00:41,600 --> 00:00:43,680 Speaker 1: Doritos at the bottom of a curbside trash can in 14 00:00:43,720 --> 00:00:48,480 Speaker 1: North Carolina, which is correctly an a possum. We spoke 15 00:00:48,479 --> 00:00:51,600 Speaker 1: with Richard Osfeld, senior scientist at the Caree Institute of 16 00:00:51,640 --> 00:00:55,319 Speaker 1: Ecosystem Studies in Millbrook, New York. He said, folks get 17 00:00:55,400 --> 00:00:58,320 Speaker 1: very confused about this. I've had people tell me triumphantly 18 00:00:58,360 --> 00:01:01,400 Speaker 1: that they discovered building plans for possum nest boxes and 19 00:01:01,400 --> 00:01:03,640 Speaker 1: that they planned to install dozens of them to encourage 20 00:01:03,640 --> 00:01:06,760 Speaker 1: opossums to multiply on their property. But when I looked 21 00:01:06,800 --> 00:01:09,520 Speaker 1: up the plans, they were designed for brush tailed possums 22 00:01:09,520 --> 00:01:14,959 Speaker 1: in Australia, completely useless for apossums in North America. So 23 00:01:15,360 --> 00:01:19,040 Speaker 1: with that part settled, opossums aren't that gross, even if 24 00:01:19,080 --> 00:01:21,720 Speaker 1: they wouldn't mind taking that multipad tie from the back 25 00:01:21,760 --> 00:01:24,520 Speaker 1: of your refrigerator off of your hands. They may look 26 00:01:24,560 --> 00:01:27,560 Speaker 1: a little creepy, what with that long, hairless, prehensile tail, 27 00:01:27,840 --> 00:01:31,039 Speaker 1: the mouthful of haphazard teeth, and the beady eyes, but 28 00:01:31,080 --> 00:01:34,559 Speaker 1: apossums are the fastidiously groomed and most likely disease free 29 00:01:34,680 --> 00:01:39,880 Speaker 1: wildlife heroes of your neighborhood. It's a common misconception, possibly 30 00:01:39,880 --> 00:01:43,560 Speaker 1: prompted by their bumbling swagger, that apossums often carry rabies 31 00:01:43,640 --> 00:01:46,680 Speaker 1: or a distemper. In fact, they rarely get these diseases 32 00:01:46,720 --> 00:01:49,520 Speaker 1: because their body temperature is too low to make them susceptible. 33 00:01:50,200 --> 00:01:53,520 Speaker 1: Not only do apossums not carry these diseases, the presence 34 00:01:53,520 --> 00:01:55,600 Speaker 1: of an opossum in your yard is your best bet 35 00:01:55,640 --> 00:01:59,760 Speaker 1: for combating lime disease. A two thousand nine study explored 36 00:01:59,800 --> 00:02:02,840 Speaker 1: whether black legged ticks. The disease vector for lime disease 37 00:02:03,240 --> 00:02:07,920 Speaker 1: might be regulated by wildlife that they parasities of fifteen 38 00:02:08,000 --> 00:02:11,400 Speaker 1: forest dwelling mammals and ground nesting birds. Opossums were the 39 00:02:11,480 --> 00:02:14,120 Speaker 1: only ones to destroy the vast majority of all of 40 00:02:14,160 --> 00:02:16,320 Speaker 1: the black legged ticks that tried to feed on them. 41 00:02:16,560 --> 00:02:22,400 Speaker 1: Over Ostfeld, who co authored the study, said, our calculations 42 00:02:22,440 --> 00:02:25,320 Speaker 1: indicated that a single opossum is capable of killing several 43 00:02:25,360 --> 00:02:28,200 Speaker 1: thousand larval ticks per week during the late summer peak. 44 00:02:28,800 --> 00:02:31,320 Speaker 1: We also know that of those ticks that do successfully 45 00:02:31,320 --> 00:02:34,040 Speaker 1: feed on an opossum, only a small fraction will become 46 00:02:34,040 --> 00:02:38,040 Speaker 1: infected with the lime disease bacterium, so apossums are protective 47 00:02:38,080 --> 00:02:42,760 Speaker 1: in two ways, killing ticks and preventing infection. A study 48 00:02:42,800 --> 00:02:45,560 Speaker 1: by the same research team published in July ten in 49 00:02:45,560 --> 00:02:48,320 Speaker 1: the journal Ecology found that tick born disease risk was 50 00:02:48,400 --> 00:02:52,680 Speaker 1: reduced in areas where opossums were present. For an animal 51 00:02:52,720 --> 00:02:55,160 Speaker 1: that does more than its fair share of hobbling into 52 00:02:55,160 --> 00:02:57,680 Speaker 1: traffic and is known for flopping over like a corpse 53 00:02:57,680 --> 00:03:00,919 Speaker 1: at the merest whiff of danger, apossums are perhaps surprisingly 54 00:03:00,960 --> 00:03:04,799 Speaker 1: intelligent to begin with weak eyesight at a nocturnal nature. 55 00:03:04,840 --> 00:03:07,560 Speaker 1: Both contribute to the fact that you're probably more familiar 56 00:03:07,560 --> 00:03:09,359 Speaker 1: with the side of a dead apossum than a live one. 57 00:03:10,040 --> 00:03:13,640 Speaker 1: In addition, their primary defense mechanism, playing dead is almost 58 00:03:13,760 --> 00:03:17,480 Speaker 1: entirely involuntary, a reaction to extreme stress that leaves the 59 00:03:17,520 --> 00:03:19,520 Speaker 1: apostum in a coma for a few minutes to a 60 00:03:19,560 --> 00:03:22,640 Speaker 1: couple of hours, and a comatose apossum can take a 61 00:03:22,639 --> 00:03:25,959 Speaker 1: beating that would kill other animals their size. This, then, 62 00:03:26,200 --> 00:03:28,480 Speaker 1: is a great strategy if your mortal enemy is a bear, 63 00:03:28,800 --> 00:03:32,360 Speaker 1: but not so great if it's a toyota. So if, 64 00:03:32,520 --> 00:03:35,240 Speaker 1: for example, your dog corners an opossum one night in 65 00:03:35,240 --> 00:03:38,480 Speaker 1: the backyard, don't worry. The apostum may hiss and show 66 00:03:38,520 --> 00:03:41,240 Speaker 1: its teeth in an attempt to look scary because it's frightened, 67 00:03:41,400 --> 00:03:43,240 Speaker 1: but the last thing it wants is to tangle with 68 00:03:43,280 --> 00:03:46,200 Speaker 1: your four legged friend. It will invariably lay down and 69 00:03:46,240 --> 00:03:49,760 Speaker 1: play dead until the threat gets bored and passes. Apossums 70 00:03:49,800 --> 00:03:53,360 Speaker 1: are non aggressive, docile creatures, far more afraid than they 71 00:03:53,360 --> 00:03:58,480 Speaker 1: are to be feared, and they're also fastidiously clean. Like cats, 72 00:03:58,480 --> 00:04:01,480 Speaker 1: apossums are constantly grimming themselves with their paws and tongue, 73 00:04:01,800 --> 00:04:04,200 Speaker 1: partly in order to make sure they're parasite free, but 74 00:04:04,280 --> 00:04:06,960 Speaker 1: also to keep themselves cool. They lack sweat glands, so 75 00:04:07,040 --> 00:04:10,240 Speaker 1: grooming is like apossum air conditioning, and they do it 76 00:04:10,280 --> 00:04:14,920 Speaker 1: to keep themselves smelling like well nothing. As we've established, 77 00:04:14,920 --> 00:04:17,479 Speaker 1: apossums aren't great at protecting themselves in a standoff with 78 00:04:17,520 --> 00:04:20,640 Speaker 1: a predator, so it behooves them to stay odor neutral. 79 00:04:21,320 --> 00:04:23,560 Speaker 1: Part of the reason apossums have the reputation for being 80 00:04:23,600 --> 00:04:26,440 Speaker 1: smelly has to do with one other defense mechanism, the 81 00:04:26,480 --> 00:04:30,200 Speaker 1: smell of death. Once an opossum goes into its theatrical coma, 82 00:04:30,400 --> 00:04:32,800 Speaker 1: if a predator continues to mess with it, the opossum 83 00:04:32,880 --> 00:04:35,640 Speaker 1: may excrete a smelly mucus from glands in its anus. 84 00:04:36,200 --> 00:04:39,360 Speaker 1: This has been a signal, Hey, this apossum is definitely dead, 85 00:04:39,560 --> 00:04:42,360 Speaker 1: and possibly so entirely dead that it'll make you sorry 86 00:04:42,400 --> 00:04:46,600 Speaker 1: you ate it. Speaking of, apossums are really smart about 87 00:04:46,600 --> 00:04:49,520 Speaker 1: what they eat, because it turns out they have great memories. 88 00:04:50,120 --> 00:04:52,600 Speaker 1: Once an apostum tastes a chemical that doesn't agree with it, 89 00:04:52,839 --> 00:04:54,640 Speaker 1: it will remember and avoid the smell of it for 90 00:04:54,680 --> 00:04:58,000 Speaker 1: a year afterwards. Though apossums are immune to some things, 91 00:04:58,000 --> 00:05:02,560 Speaker 1: that would poison other mammals, including most snake venoms. Apossums 92 00:05:02,560 --> 00:05:07,239 Speaker 1: are biologically fascinating, which led to some confusion among earlier 93 00:05:07,279 --> 00:05:10,360 Speaker 1: Europeans in the New World. Their story was the male 94 00:05:10,400 --> 00:05:13,720 Speaker 1: opossum made it through the female apossums snout, which led 95 00:05:13,760 --> 00:05:16,880 Speaker 1: to her sneezing out her babies into her marsupial pouch. 96 00:05:17,560 --> 00:05:21,479 Speaker 1: Of course, this is not scientifically accurate, but apossums definitely 97 00:05:21,520 --> 00:05:24,640 Speaker 1: do things a little differently. First of all, a male 98 00:05:24,680 --> 00:05:27,359 Speaker 1: apossum has a forked penis, but it's not meant for 99 00:05:27,360 --> 00:05:30,680 Speaker 1: the female's nostrils. Female apossums have a double vagina and 100 00:05:30,760 --> 00:05:35,160 Speaker 1: twin uteri. Apostsum embryos developed for about thirteen days until 101 00:05:35,160 --> 00:05:37,400 Speaker 1: they're large enough to migrate down the birth canal and 102 00:05:37,440 --> 00:05:40,520 Speaker 1: emerge about the size of house flies to continue developing 103 00:05:40,560 --> 00:05:43,680 Speaker 1: in the mother's pouch. Although dozens of them will be born, 104 00:05:43,760 --> 00:05:46,880 Speaker 1: the mother only has thirteen teats, so that's probably how 105 00:05:46,880 --> 00:05:54,599 Speaker 1: many will be able to survive into adulthood. Today's episode 106 00:05:54,640 --> 00:05:56,960 Speaker 1: was written by Jescelyin Shields and produced by Tyler Clang. 107 00:05:57,360 --> 00:05:59,240 Speaker 1: Brain Stuff is a production of I Heart Radio's How 108 00:05:59,240 --> 00:06:01,200 Speaker 1: Stuff Works. For more in this and lots of other 109 00:06:01,240 --> 00:06:04,400 Speaker 1: animal tails. Visit our home planet, how stuffworks dot com 110 00:06:04,440 --> 00:06:06,600 Speaker 1: and for more podcasts. For my heart Radio, visit the 111 00:06:06,640 --> 00:06:09,360 Speaker 1: I Heart Radio app, Apple Podcasts, or wherever you listen 112 00:06:09,440 --> 00:06:10,279 Speaker 1: to your favorite shows.