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AnimalsTranscript
00:00 They're the Mike Tysons of the serpent world.
00:05 Short and stocky, they move at lightning speed, packing mighty punches, laced with hardcore
00:14 venom.
00:18 From the American wild west to the steamy African jungles, vipers are notorious for
00:24 their bad attitudes, diamond-shaped heads, and the longest snake fangs on earth.
00:37 But these super snakes aren't just a family of cold-blooded killers.
00:44 The females have a softer side when it comes to family.
00:48 Thelma, Velvet, and Nala are three species of viper with one thing in common - basic
00:58 maternal instinct.
01:01 But is this what makes them so successful in the game of survival?
01:07 Enter the lab to experiment with snake bites and venom, dissect specimens, and study anatomy
01:14 as we explore the lives of these viper queens.
01:27 Scavengers with a taste for flesh have picked up the scent of new life in the air.
01:37 Born into the wilds of New Mexico, these western diamondback rattlesnake babies are instantly
01:43 at the mercy of the elements and other creatures they share their home with.
01:54 Only minutes old, their survival instincts are already firing up, even if they don't
02:05 achieve the desired effect just yet.
02:11 With no way to defend themselves, newborns are easy targets for predators, like this
02:21 king snake.
02:30 But they've got backup.
02:38 This is Thelma, and she is one mean mama.
02:43 Unusual for most snake species, but characteristic for vipers, their mother's still around.
02:53 Thelma and her offspring will only remain together for a few weeks until they're strong
02:58 enough to head off into the wilderness on their own.
03:03 In the meantime, the family's keeping a low profile, and her presence alone does a good
03:10 job of discouraging would-be predators.
03:20 Young king snakes hunt other snakes, and baby rattlesnakes make for easy prey.
03:48 Thelma's not shy to let her enemies know she's around.
03:54 A rattled warning is a rattlesnake's first line of defense.
04:00 It's the signature sound of the desert, synonymous with danger.
04:04 It's the reason for Thelma and her family's infamous status as symbols of the American
04:10 Southwest.
04:13 King snakes shed their entire skin every few months, but rattlesnakes are born with a tiny
04:20 button at the end of their tails, and this becomes the matrix for their rattles.
04:28 Each time they shed, a modified scale remains behind and adds another segment to the rattle.
04:39 Rattling at up to 2,000 cycles per second, the shaker muscles used to vibrate the segments
04:44 are some of the fastest known to man, and they have an all-or-nothing function.
04:52 The muscles work only at full capacity, and they don't get tired.
05:02 It's a similar level of muscle control that links Thelma to her African cousin, but in
05:10 quite the opposite way.
05:19 Velvet is a West African gaboon viper, or agar.
05:27 She is silent, solitary, and is rarely seen.
05:35 Her beautifully tapestried scales render her invisible on the forest floor, but her quiet
05:43 demeanor and incredible loveliness belies her deadly nature.
05:51 It's like a highly trained assassin, capable of infinite patience and extreme muscle control.
06:03 She can wait motionless for days, weeks, or even months, and then unleash a sudden, powerful
06:14 attack.
06:16 Armed with fangs up to two inches long, gaboon vipers not only have the longest snake fangs,
06:24 they're also the largest and heaviest viper species in existence.
06:31 But Velvet's not aggressive and prefers to stay hidden.
06:36 She rarely attacks, and then only to predate or defend herself.
06:46 Most of the time, no one even knows she's around until it's too late.
07:08 Velvet and Thelma the rattlesnake live worlds apart, but they share a simple mission in
07:14 life.
07:15 To stay alive and grow their families.
07:22 It's a game of survival, but what happens if you don't have Thelma's early warning system,
07:28 her badass attitude and legendary status?
07:33 Or Velvet's size, stealth, lethal patience, and immense weaponry?
07:43 Meet Nala.
07:46 She's not as showy as Thelma, nor as beautiful as Velvet, but she belongs to a group of tough
07:52 little vipers, the puff adders.
07:58 They're small, but formidable killers, and they're going about this survival game a little
08:03 differently.
08:05 They've built a fearsome name for themselves through sheer numbers and tenacity.
08:12 Spread throughout Africa and southern Arabia, puff adders occupy one of the widest distributions
08:18 of all viper species.
08:22 They're adaptable and hardy, and can survive in a wide range of habitats, in the wild and
08:29 alongside humans.
08:33 Puff adders are masters of disguise.
08:38 Their skins come in a range of color variations, sometimes making them hard to identify.
08:46 But for one distinguishable feature, the chevron markings on their backs.
08:58 Displaying such blatant warning signs on their own bodies, and living so close to humans,
09:04 puff adders have had to learn to operate under the radar.
09:12 Velvet has few, if any, natural predators as an adult, and rarely comes into contact
09:17 with humans.
09:19 While Thelma does, she plays fair, giving her enemies a chance, warning them before
09:24 they get too close.
09:26 But puff adders don't run from fights.
09:36 When faced with danger, they hunker down.
09:40 Classic viper ambush tactic.
09:44 Nala has attitude.
09:47 She fights dirty, and it's earning her a bad reputation.
09:56 For Nala the puff adder, life in an African village is fraught with danger.
10:03 Dogs don't like her, and neither do people.
10:10 When she senses a potential threat nearby, like most vipers, fleeing isn't her first
10:17 reaction.
10:19 While Thelma the rattlesnake warns off her enemies, Nala prefers to draw as little attention
10:26 to herself as possible.
10:30 She freezes, her camouflage allowing her to blend into her surroundings.
10:39 She waits for the threat to pass.
10:44 In this way, Nala conserves her energy and venom for when it's really needed.
10:52 It's a good strategy.
10:54 If discovered, she could be hurt, or even killed, by the villagers.
11:04 But sometimes, she's so well camouflaged, perceived threats unknowingly get too close,
11:13 and are often bitten when they accidentally step too near, sometimes even on top of, a
11:19 puff adder.
11:23 This shoot-first, ask-questions-later attitude has earned puff adders a bad reputation.
11:30 But it's not entirely undeserved, because puff adders kill humans every year.
11:39 Death from a western diamondback rattlesnake bite is virtually unheard of, and no fatalities
11:45 from a gaboon viper bite have ever been recorded.
11:49 So in comparison, Nala the puff adder is deadly.
11:55 Yet her motives are usually misunderstood.
12:02 Puff adders often live in close proximity to human settlements, because their prey do.
12:18 But venomous snakes lurking about are a hazard to humans.
12:26 In most cases, puff adders bite in defense, or when they've mistaken a limb for prey.
12:36 The results of such an error can be horrific.
12:43 Puff adder venom is predominantly cytotoxic.
12:46 It destroys cell tissue with devastating efficiency.
12:52 But it's not only humans that fall victim to these feisty little vipers.
12:57 In the wild, animals create pathways through the bush known as game trails.
13:04 For creatures like tiny rodents, to the world's largest land mammals, these trails provide
13:11 easier movement, and often lead to waterholes or good feeding grounds.
13:22 And it's along paths like these that puff adders will position themselves to wait for
13:27 prey.
13:38 But when unsuspecting victims, weighing thousands of pounds, tread too close for comfort, a
13:46 little 13-pounder puff adder can defend itself in a mighty way.
13:53 It doesn't seem possible that a bite from a tiny snake could pierce the skin of a rhino,
13:59 let alone do any serious damage.
14:02 But here's evidence to the contrary.
14:06 A bite caused such severe necrosis on the leg of this black rhino that her entire foot
14:13 rotted off, leaving behind just bone fragments and flaps of decaying flesh.
14:23 Trauma like this would render most animals immobile, ensuring a slow and painful death
14:28 due to starvation and septicemia.
14:33 It's an extreme example of what happens when a puff adder bite is left untreated.
14:41 With cases like these and human deaths on their hands, surely puff adders must be more
14:47 dangerous than their cousins.
14:52 They are, but for reasons other than we think.
14:58 When tested, Thelma the rattlesnake's venom proves to be primarily hemotoxic, which attacks
15:03 the blood.
15:04 It can be rapidly lethal to natural prey, but it's not nearly as dangerous to the average
15:10 healthy adult human, which is why fatalities are virtually unheard of.
15:16 In contrast to hers, Nala the puff adder and Velvet the gaboon viper each produce their
15:23 own individual mix of tissue-destroying venom containing cytotoxins, and when compared,
15:30 puff adder venom proves to be more potent than a gaboon viper's drop for drop.
15:38 But gaboon vipers have a much more complex array of toxins, which makes it more deadly
15:44 due to the devastating effect it has on cells of the body.
15:50 A puff adder bite will cause immense pain, inflammation, bleeding that can't be stopped,
15:57 and skin cells to self-destruct.
16:00 Venom left to run its course could cause death.
16:06 A gaboon viper's venom will do something similar, but an extreme, because it works faster and
16:12 comes with extras.
16:14 Tiny blood clots form throughout the body and can cause organ failure, a powerful array
16:20 of neurotoxins to attack the nervous system, myotoxins the muscular tissue, cardiotoxins
16:27 the heart.
16:28 These are just some of the extras to be found in the gaboon's venom cocktail.
16:36 But that's not all.
16:39 Because gaboon fangs are so long and their venom glands so large, they dispense much
16:44 more venom, much deeper into the bodies of their victims.
16:53 A bite from a gaboon would be considered an urgent, life-threatening medical emergency
16:57 for a human, and certain death for prey.
17:03 Yet puff adders are considered more dangerous to humans than gaboon vipers for a very simple
17:10 reason.
17:14 Gaboons favor forest habitat, so it's not often they come into contact with people.
17:20 And as adults, they don't have many, if any, predators.
17:25 So they're not naturally aggressive, because they usually have no need to be.
17:32 But life for a puff adder like Nawa is totally different.
17:38 With a number of natural predators and living in a range of habitats, including human settlements,
17:44 puff adders have learned to stand their ground with fight before flight.
17:55 But meeting an enemy head on is risky, so Nawa sticks to the shadows.
18:04 It's just safer that way.
18:10 Lucky for Thelma, her rocky outcrop home is far from humans on the ranches in the valley
18:16 below.
18:20 It's a peaceful place to live.
18:23 Usually.
18:25 Trouble, in the shape of a strapping young green-colored male rattlesnake, is brewing
18:32 down in the valley.
18:35 And he is slowly heading her way.
18:38 In these circumstances, the sound of her rattle alone isn't going to keep the peace.
18:53 Far below Thelma the rattlesnake's rocky outcrop home, trouble's brewing.
19:06 Living in this American Southwest valley isn't for the faint-hearted.
19:24 A rattled warning means nothing here.
19:29 The sound is lost in the mayhem.
19:41 The only way to survive this place is to keep a low profile.
19:47 But it's not that easy.
19:56 Everyone's watching, everyone's on constant alert for danger.
20:02 His reputation alone makes Cody the male rattlesnake an unpopular guy around these parts.
20:10 But hanging around the ranch has its rewards.
20:15 All Cody's favorite treats are readily available.
20:21 Whenever he wants them.
20:25 So what if he's got to duck and dive and keep things low-key?
20:27 It's well worth the effort.
20:34 And he's really good at it.
20:49 But Cody's real party trick is something else.
20:56 He doesn't need to worry about humans catching him.
21:00 Because he can operate under the cover of darkness.
21:05 To the naked eye, the inside of the barn is pitch black.
21:11 But Cody and his rattler group members are equipped with a particular skill that many
21:16 of their cousins like Velvet and Nala don't have.
21:22 It's like having the coolest superpower on earth.
21:29 Cody has thermal imaging abilities.
21:34 Snake species sharing this skill are also known as pit vipers.
21:39 On either side of their snouts, right at the very end between their eyes and nostrils,
21:44 are tiny little pits.
21:47 These house their heat-sensing organs, which are always two to three degrees cooler than
21:52 the rest of their body, keeping their sensitivity maxed at all times.
22:01 A small membrane lines these pits, hanging in a bony chamber, which allows it to heat
22:07 and cool rapidly.
22:09 In doing so, making it hypersensitive to changes in temperature in the snake's immediate
22:14 vicinity at any time of day or night.
22:19 The nerve cells of the membrane produce a protein that is only activated when temperatures
22:23 of around 82 degrees Fahrenheit or higher are detected, which is roughly the measure
22:30 of body heat of a warm-blooded animal within a meter of the snake.
22:36 When this happens, nerve impulses based on the temperature readings sent to the brain
22:42 create thermal images of the prey item on offer.
22:48 Cody can single out living creatures in the darkness, without them even realizing he's
22:56 there.
23:09 But something's up.
23:16 He has complete advantage of the situation, but he's not taking the opportunity for a
23:21 meal.
23:23 Is it possible for a rattlesnake to turn vegan?
23:30 While Cody ignores his dinner, on the other side of the world, in her African village
23:35 home, Nala the puff adder has no such dietary inhibition.
23:43 Like Cody, she's weighed up the pros and cons of hanging around humans and their snarly
23:49 watchdogs.
23:50 But even that's not enough to put her off.
24:00 Not when the place is crawling with ready-made meals at all hours.
24:08 She's still got to be careful, though.
24:32 Once she's in position, it's easy pickings.
24:54 A quick stab of her fangs injects enough venom to ensure the rat doesn't get far, making
25:08 it easy to follow, find, and eat.
25:24 But one isn't enough.
25:27 Nala is going to make the most of her visit to this village.
25:45 It may look like Nala's being a glutton, but she's preparing for a big event, one that's
25:50 going to put her out of action for a while.
25:56 So she's taking full advantage of this opportunity.
26:07 Deep in the forest, Velvet the gaboon viper is also hungry.
26:13 But she's got a whole different way of doing things.
26:24 It might not look like she's doing much, and that's all part of the plan.
26:34 When the time is right, all hell will break loose.
26:45 Velvet settles in to wait.
26:53 As predators, snakes aren't exactly armed with the best hunting equipment.
26:58 They don't have legs to chase down prey, claws to grip, nor teeth for tearing flesh.
27:04 So they've had to come up with a different strategy to find their niche as sophisticated
27:09 predators.
27:14 Velvet and her gaboon viper relatives have outdone themselves.
27:27 They aren't particularly graceful when climbing trees, so they stick to the ground.
27:38 The forest floor is their domain, and they've made it their own.
27:46 Intricate patterns and colors on Velvet's back allow her to disappear into the leaf
27:51 litter.
28:01 Once settled, she doesn't move.
28:10 But the slightest motion can betray her position.
28:15 It may look like Velvet's just chilling out, but to keep this still actually takes
28:23 an extreme amount of muscle control.
28:31 While waiting in ambush, Velvet keeps firm, responsive muscles, practicing what's called
28:37 active stillness.
28:39 But she needs to remain absolutely motionless.
28:42 Her muscles need to be ready for sudden bursts of activity at any given moment.
28:48 To do this, alternate muscle bundles are either active or relaxed, continually rotating to
28:55 maintain muscle tone and prevent one group from getting tired.
28:59 In this way, Velvet conserves her energy and muscle power, so she's always ready to launch
29:06 an attack.
29:10 She only gets one chance.
29:16 If she loses the element of surprise, it could be weeks before another potential prey animal
29:21 comes along.
29:23 She's got to get it right the first time.
29:31 But if she gets the strike right, rest is easy.
29:45 Velvet the Gaboon Viper is lying in wait for prey.
29:51 She's kept still for days.
29:55 Her muscles are like a hair trigger, ready to strike in a split second.
30:01 But that's not all she's relying on to make a successful kill.
30:06 Velvet may not have any limbs, but she's equipped with one of the most advanced hunting and
30:11 defense systems in the animal kingdom.
30:14 Venom.
30:17 It's Velvet's ultimate weapon, allowing her to kill or at least immobilize prey before
30:22 they have any chance to escape.
30:25 But to dispense this modified toxic saliva, she needs a specialized injection system.
30:32 And Velvet's just happens to be the deadliest in the world.
30:40 She's capable of injecting up to 600 milligrams of venom in a single bite.
30:48 It takes only a hundred to kill an adult human.
30:54 Like all vipers, her fangs lie flat against the roof of her closed mouth.
31:00 When hunting, as she opens her mouth, they unhinge and swing down, ready to stab into
31:05 a victim.
31:06 But it's not easy to bite and then release when you have rows of long, backward-pointing
31:13 teeth.
31:16 To get them in and back out of a victim's body, it sometimes looks as if they're chewing.
31:23 This lethal combination of hardware and chemicals make her a deadly predator.
31:31 But she's got one more trick up her sleeve to guarantee success.
31:39 Patience.
31:46 Any number of potential prey could venture past.
31:50 Velvet isn't picky.
31:51 She'll eat anything from rodents and birds to small antelope and monkeys.
31:57 She's got a knack for it.
32:22 A slight miscalculation makes no difference.
32:46 Once she's set her sights on a target, there's no chance for escape.
32:52 Her strike isn't the fastest in the snake world, but at over 20 feet per second, it
32:58 does the job.
33:01 The shock of the attack stuns the bird, while the complex venom cocktail rapidly floods
33:07 its body.
33:11 As she waits for her prey to die, Velvet adjusts her fangs.
33:19 They can really get in the way sometimes.
33:31 Within 10 minutes, it's all over and lunch is ready.
33:38 Eating is a specialized process.
33:42 Velvet unhinges her jaw to allow her to open her mouth wide enough.
33:47 Using rows of teeth to latch on, she drags her prey to a safe place where she can eat
33:54 in peace.
33:59 Back at the ranch, it turns out that Cody, the male rattlesnake, hasn't turned vegan
34:04 after all.
34:15 But he's clearly not hungry either.
34:20 Snakes are able to control the volume of venom they inject, even withholding it completely
34:26 when dishing out a warning to stay away.
34:31 This rat has had a lucky escape with only a dry bite from Cody.
34:38 There's only one reason he would decline the opportunity of a meal once again.
34:48 With a very slow metabolism, it could take him days, if not weeks, to digest a meal as
34:54 big as that rat.
34:58 He can't afford to be out of action that long, because he's on a mission.
35:07 It's not a meal he's after.
35:18 He's looking for a mate.
35:42 Cody has thrown him headlong into a love triangle, with a huge pink-colored male as the competition.
35:51 Cody has no idea of who Thelma is, nor that this is her home.
35:57 But the fact that another male, with a really bad attitude, is hanging around, tells Cody
36:02 all he needs to know.
36:05 He's found a female worth fighting for.
36:16 Like boxers meeting in the ring, Cody sizes up his pink opponent.
36:23 It's all about moves, making the first, and dominating with each.
36:46 With no limbs to make things awkward, they fight with their whole bodies.
36:54 But it's not about throwing punches.
36:57 Neither intends to hurt or maim his rival.
37:03 It's merely a ritual, a dance of domination.
37:26 The twists and turns and thrusts are a show of strength.
37:49 A power struggle, meant to single out the stronger male.
37:57 But he needs to leave the fight unharmed and ready to claim his prize of mating with the
38:02 female.
38:09 The other male may be pink in color, but he doesn't fight like a girl.
38:34 Pinned to the ground by the weight of his rival, Cody knows he's out of the game.
38:59 Defeat means eating dirt, and a humiliating exit.
39:09 It's a devastating blow for Cody.
39:14 He's foregone food, traveled long distances, and risked injury through fighting.
39:21 But it's all been for nothing.
39:23 He didn't get the girl.
39:26 But Thelma's not just not into him.
39:30 She's not into anyone at the moment.
39:35 Cody the male rattlesnake has just lost his fight for Thelma.
39:40 But while the other male has won the battle, it doesn't mean he's won Thelma's heart.
39:48 She's just had her babies and isn't interested in mating right now.
39:55 It will take time for Thelma's body to recover from giving birth.
40:00 While the youngsters are around, she gets no alone time to stage an ambush for food.
40:07 But once they leave home, she'll rebuild her strength and maybe consider mating again in
40:12 the spring.
40:17 For now, no amount of nudging and rubbing from the pink male is going to turn her on.
40:25 Coiling against him, the flicking tail dismisses him.
40:33 He has no choice but to leave reluctantly.
40:48 He'll have to try his moves elsewhere.
40:55 Snakes mate in a ritual of gently rubbing bodies.
41:01 The male nudges the female with his snout, bumping her lightly as if to cajole her.
41:15 Their bodies caress and tongues flicker as the male tastes the female's pheromones, testing
41:23 if she's ready to mate.
41:31 When the female is aroused, she'll lift the base of her tail and they'll mate, like these
41:41 puff adders are doing.
41:50 The males tend to do most of the work.
41:58 Perhaps the females pace themselves during mating, because just one session can sometimes
42:03 carry on for up to three hours.
42:07 Yet it's the coming months they'll most need their energy for, as they have big decisions
42:13 to make.
42:15 Females hold all the cards when it comes to making babies.
42:22 They can store sperm from one mating session for up to five years before it starts to deteriorate.
42:29 When the female feels the time is right and conditions are good enough to bring offspring
42:33 into the world, she'll dip into her sperm bank and impregnate herself, or become gravid.
42:41 Fertilization will occur and eggs will form.
42:44 But a female viper's job doesn't end with laying the eggs and leaving them to fate like
42:50 most snakes.
42:52 Instead, their bodies become living incubators.
42:58 When the young are ready to hatch, mothers give birth to live snakelings.
43:12 Vipers are ovoviviparous, so they produce eggs.
43:16 But the eggs have a soft membrane instead of a shell, and they develop inside the mother's
43:22 body.
43:28 It's not clear whether mothers share nutrients with the developing embryos, so it may seem
43:34 like a waste of time for Nala to have lugged over 20 eggs around for months.
43:41 It's a great sacrifice on a mother's part to carry the growing embryos.
43:48 As she gets heavier, it gets harder to hunt, and her own body loses condition, just as
43:53 Thelma's did.
43:56 But by carrying their embryos as they develop instead of laying eggs, Nala and Thelma, like
44:03 most viper moms, have given their offspring the best possible chance at life.
44:09 And hardships aside, viper moms have the best of both worlds in the animal kingdom.
44:17 Now that Nala has given birth, her maternal duties are done.
44:23 She doesn't provide any postnatal care, like suckling, grooming, babysitting, training.
44:31 Imagine doing that for over 20 babies.
44:38 But it could have been worse.
44:41 The record number of offspring born to a puff adder, of any snake species, is 156.
44:53 Within two weeks of birth, usually once they've shed for the first time, Nala's youngsters
44:59 will go their own way.
45:06 Equipped with fangs and venom, they're fully independent and perfectly capable of surviving
45:14 on their own.
45:18 Life in the wild is a continuous battle for survival, and vipers take it seriously.
45:28 They're a super family of snakes, each equipped with a different set of skills and sophisticated
45:35 weapons, born ready to lead lives as proficient killers.
45:42 But it's these traits, combined with the females' basic maternal instincts, their softer sides,
45:49 when it comes to family, that ultimately gives the viper queens their edge for success over
45:55 many other snake species.
45:58 (snake roaring)
46:00 (upbeat music)
46:02 (upbeat music)