When Hormones Turn Animals Into Survival Machines | Moody Beasts

[00:00:07][music] Then the handoff.

[00:00:17]Turning strays into finger food takes finesse.

[00:00:25][music] Hormones.

[00:00:30]are the rocket fuel of survival.

[00:00:34][music] They make wildlife its wildest [music] and every animal a moody [music] beast.

[00:00:47]This episode they pit their kids against [music] each other.

[00:00:52]They kill other parents young to make way for their own.

[00:00:57]All to pull off the hardest job on the planet, parenthood.

[00:01:06][music] [music] There are two questions new life is least prepared for.

[00:01:23]How did I get into this mess?

[00:01:25]>> [music] >> And how do I get out of it?

[00:01:29]The answer is stress [music] hormones.

[00:01:34]There's one way bears know how to avoid stress.

[00:01:37][music] By avoiding other bears.

[00:01:43]They're loners.

[00:01:45]So, what happens when they have to get in each other's place?

[00:02:02]A grizzly is no social butterfly.

[00:02:09]He prefers his solitude.

[00:02:14]This is his man cave, a territory in Alaska that might be bigger than Luxembourg.

[00:02:28]Same for Little Bear.

[00:02:31]For years, she might only hang out with her mom and her siblings.

[00:02:41]But Little Bear is in for a rude awakening.

[00:02:47]She won't be solo for long.

[00:02:52]Late summer and fall, a feast explodes on the scene.

[00:02:59]Salmon surge up river. From their home in the Pacific to the headarters of Brooks River, where they were spawned.

[00:03:09]They come by the hundreds of thousands.

[00:03:11][music] Heading them off is a whole lot of appetite.

[00:03:21]The bears come out of the woodwork.

[00:03:41]Little Bear and all the grizzlies need to bulk up for the winter hibernation.

[00:03:50][music] They can gorge on 40 kilos a day.

[00:03:58]That's a lot of fish.

[00:04:00]Without the strength or the experience of their mom, the cubs have to share what she catches.

[00:04:07]And there's a lot of competition.

[00:04:12]Little bear looks left, she looks right.

[00:04:16]All she sees is the same thing. [music] The stretch of river has turned into grizzly central.

[00:04:26]For animals that are used to being alone, this is stressful.

[00:04:33]All the best positions are taken by the bears who are the most aggressive with the dominant ones in [music] prime position at the top of the fords.

[00:04:45]Little bear is stuck down river with the lowest quality fish because the bruiser up river is stoked with testosterone.

[00:05:02]If little bear doesn't bulk up on testosterone herself, she'll end up like a lot of bears here, loaded down with that hormone for losers, cortisol.

[00:05:18]It kicks in when a body needs a boost.

[00:05:22]Cortisol is a lifesaver to make up for starvation and hard times. It taps into our secret stores of energy right when we need them most.

[00:05:33][music] Overdose and it can be a killer. It can run riot on a bear's immune system and deplete her reserves.

[00:05:43][music] The grizzlies here who don't have high enough testosterone counts could be binging on cortisol instead.

[00:05:51]A fake little bear had better avoid.

[00:05:58]Being with others hard and fair, [music] but being a cortisol loser is even harder.

[00:06:12][music] They'll travel for months.

[00:06:25]Thousands will [music] die along the way.

[00:06:32]Somebody must be thinking, "Are you sure this is such a great plan?

[00:06:50]In Africa's Mara Serengeti region, there are up to half a million wilderbeasts born every [music] year. During peak periods, this can be as many as 14,000 a day.

[00:07:04]Before they reach their first birthday, one in four will die.

[00:07:09]The reason? It starts [music] the moment a calf is born.

[00:07:15]Mom gives her a helping nudge.

[00:07:21]But she has to be on her [music] feet in minutes. Seven on average.

[00:07:29]Otherwise, she'll be cat food.

[00:07:35]That would be like us learning to walk within half [music] an hour of being born.

[00:07:42]It could be the single most stressful start to life in the world. From day one, a wilderbeast is a worry machine.

[00:07:52]In fact, the whole herd is always [music] on edge.

[00:07:59]For good reason. No sooner does the calf hit [music] the ground running than they're all on the move on an epic journey.

[00:08:13]What's the rush?

[00:08:15]It's May, the beginning of the dry [music] season. A million and a half wilderbeast all get the same urge at the same time.

[00:08:24]Let's [music] get where the grass is greener.

[00:08:28]The new calf is swept up in the great migration, forced to march up to 58 km [music] a day.

[00:08:37]There are no pit stops.

[00:08:40]She's not allowed to ask, "Are we there yet? [music] She faces disease, deprivation, predators, and the risk [music] of becoming an orphan.

[00:09:00]What keeps her going? Every step is being guided by a quirk of her chemistry. [music] Sure enough, a stress hormone.

[00:09:10]Glucocorticoid spikes when a wilderbeast senses less grass and feels anxious that [music] provides the extra energy she needs to get her through tough times.

[00:09:24]Super tough.

[00:09:27]The worst comes at the bank of this river.

[00:09:32]The toll collectors on this route are hungry.

[00:09:42]But hunger also drives the herd on that and their hormones.

[00:09:51]Think how powerful that jolt must be since every fiber of their being is telling them this is dangerous.

[00:10:00]It's a gamble on the numbers game. To give a wilderbeast [music] the courage to cross, it will have to rely on its stress hormones.

[00:10:30]>> [music] >> On the other bank of the river, they get their reward, survival.

[00:10:37][music] They say there's safety in numbers, [music] but really it's the hormones that push the wilderbeast through their fear and exhaustion.

[00:10:51]They help drive the species to their feeding grounds. [music] In this corner weighing 40 kilos, a male red named Joey.

[00:11:13]In this corner weighing well the same, another male red kangaroo also named Joey.

[00:11:23]Fights on.

[00:11:33]There he is, grazing away in the Australian Red Center, a quiet rue, minding his own business.

[00:11:44]When suddenly, hang on, hothead. Who does he think he is?

[00:11:52]His dad, of course.

[00:11:56]Note to self, don't get on dad's [music] bad side. But then it's not anger management that male red kangaroos need.

[00:12:04]It's boxing lessons.

[00:12:06]When he becomes an adult, he will have to brawl with other males [music] for dominance.

[00:12:14]So, while he's [music] just a young Rue, now's the time to get some practice swings in. [music] Today's match, Joey [music] versus Joey.

[00:12:30]Jukes up. [bell] [music] A kangaroo smackdown is just that. All smacks.

[00:12:44]Less punch, more poke.

[00:12:48]Right hook, left bait, stab and jab. A whole lot of bluff [music] and bluster.

[00:12:59]It's all about the skill, not the kill.

[00:13:02]These teenagers get into ritualized fighting and prep for the real thing.

[00:13:08]The middle weights take it up a notch.

[00:13:12]Kickboxing.

[00:13:16]Kangaroos have padded [music] bellies to withstand the blows and retractable scrotums.

[00:13:25]When a contender gets desperate, he kicks. The more he kicks, the more likely he's the loser.

[00:13:31]To get to be the kangaroo [music] kick takes a lot of brawl. But the real secret, it's all in the hormones.

[00:13:40][music] An adult winner might have as much as seven times the testosterone as the loser.

[00:13:47]There is a [music] trade-off. Since he's got so little fat, a hunk might have a harder time surviving during drought or famine, but it's worth it.

[00:13:58]The bigger his [music] biceps, the more desirable he is to a female. What could be a [music] better key to the success of a species?

[00:14:08]Raising [music] teens who can kick other teens butts.

[00:14:14][music] Take [music] parlor for instance. They could stand their ground.

[00:14:25]But then let's give that a [music] big little [music] Done.

[00:14:40][music] An impalaine has got everything going for her.

[00:14:57]Plenty of African greenery to graze.

[00:14:59][music] Plenty of young males practicing sparring for their big chance with her.

[00:15:11]and a dad who doesn't notice.

[00:15:15][music] He's too busy doing important things like seeing off rivals.

[00:15:23]All in all, it doesn't take much to learn how to survive.

[00:15:27]But every now and then, growing up in [music] Parlor really sucks.

[00:15:34]One glitch is all it takes to ruin your day.

[00:15:43]Survival depends on the next 400 milliseconds.

[00:15:49][music] How does adrenaline work? It shunts every drop [music] of energy to her limbs.

[00:15:57]It powers up every function that helps her escape. [music] This is the ultimate secret to sheer survival.

[00:16:15]But panic can also cloud her judgment.

[00:16:22]The terrorized [music] team runs straight into another line's path.

[00:16:33]Adrenaline gives prey an edge, but appetite can give predators the advantage.

[00:16:46]Fight or flight, sometimes it's no choice at all.

[00:16:54]But then hormones are game changers.

[00:16:57]They'll take a creature who's one of the most feared on the planet. A coldblooded killer, [music] who's still learning from his old grandma.

[00:17:14][music] Grandma Olra is pushing 70. [music] By wildlife standards, she's old and in the way.

[00:17:29][music] It's true for nearly every species on Earth. Once an animal has stopped reproducing, she's done for.

[00:17:37]But it's been 25 years since Granny's last calf.

[00:17:42]In fact, she's going through menopause.

[00:17:47]There are just three species in the world who do and [music] two of them are on either side of this screen.

[00:17:59]What makes them and us so unlucky?

[00:18:04][music] The answer is all about our grandkids.

[00:18:10][music] Wherever orcas occur in the world's oceans, they exploit different prey, and that demands different hunting skills, techniques that need to be taught.

[00:18:25]Venomous stingrays are a New Zealand specialty, but a young orca doesn't know scratch about how to catch one.

[00:18:35]That's where Granny comes in.

[00:18:41]First comes the trick of finding one, then nabbing it without getting stung.

[00:19:05]Then the handoff.

[00:19:09]Turning stingrays into finger food takes finesse.

[00:19:18]Orcas need their elders.

[00:19:20][music] Every stingray in sight has the scars to prove it.

[00:19:29]The orcapot keeps granny around to teach Junior the ropes.

[00:19:38]In fact, adult males who have their mothers around live longer.

[00:19:44]Her menopause is [music] caused by hormones, the ones she's missing, less estrogen.

[00:19:52]Menopause is the body's reaction.

[00:19:58][music] She may have served her purpose as a breeder, but as a teacher, she's got a lot to offer. Growing up, growing old, they go hand in hand for organs.

[00:20:12]Hormones are the rocket fuel of survival.

[00:20:20][music] They make wildlife its wildest [music] and every animal a moody [music] beast.

[00:20:33]This episode they pit their kids against each other.

[00:20:39]They kill other parents young to make way for their own.

[00:20:43]All to pull off the hardest job on the planet, parenthood.

[00:20:51][music]