- 13 hours ago
Nature has evolved a fearsome arsenal of "wildest weapons"—including crushing antlers, piercing tusks, venoms, and electrical shocks—used by animals for fighting, defense, and hunting...
Category
🐳
AnimalsTranscript
00:18More than 8 million animal species live on the planet today.
00:26Only a special few are armed with extreme weapons.
00:36Huge physical appendages growing from their bodies.
00:45Wielded in titanic battles.
00:54What gives rise to these enormous structures?
00:58When the conditions are just right, these weapons can get caught up in arms races.
01:03Are they more than just instruments of blunt force?
01:08Can you show me the biggest weapon in the animal world?
01:11Absolutely.
01:11And what can their evolution teach us about our own arms race?
01:18Three, two, one, turn.
01:40In southwest Montana is a bizarre armory, created from a collection of naturally shed antlers.
01:58Oh my god.
02:01Wow.
02:04Unbelievable.
02:09Doug Emlin is a professor of biology.
02:12He spent his lifetime trying to unlock the secrets of extreme animal weapons.
02:19I mean, look at this.
02:22This is an antler from an elk, a bull elk from here in Montana.
02:26This is 20 pounds of bone.
02:28And they, of course, produce two of them every year.
02:31Antlers are the fastest growing bones described from any living vertebrate.
02:39Nature's armory is diverse.
02:44Horns.
02:48Tusks.
02:51Stings.
02:53They can be used for attack.
02:58Or for protection.
03:03Almost any animal has a weapon of one sort or another.
03:07I mean, cats have claws.
03:08Eagles have talons.
03:10Even dogs have a respectable set of teeth.
03:14But those weapons stay small.
03:16There's nothing big or awkward or anything that would slow these animals down.
03:20Nothing sticking out of their bodies in some crazy way.
03:24But here and there, sprinkled through the tree of life,
03:27are species where their weapons are taken to an extreme.
03:33For me, I'm interested in the weapons of offense.
03:35Weapons that are used in fighting.
03:37And in particular, the weapons that are big.
03:41Those are the species that keep me awake at night.
03:54Luckily for Doug, he can find perfect subjects right on his doorstep in Montana.
04:06Look at that guy. Look at him.
04:12Rancher Doug Avril keeps elk on his land.
04:18Amongst them are a number of mature males.
04:23During the autumn rut, the antlers of these bull elk are at their most impressive.
04:32Here comes another one.
04:37They're all going to size each other up here when you get this many bulls together.
04:42This might get interesting.
04:45Fueled by testosterone, the biggest bulls are looking to assert their dominance.
04:52When it's not in the rutting season, they're relatively calm, peaceful animals.
04:57But it's kind of like a bunch of guys on Friday night at the bar.
05:14This is pretty rare.
05:16I haven't seen this all summer.
05:24You can see they're totally locked together.
05:39The larger bull on the right has won this round.
05:46But the loser still wants a fight.
05:49Got the temperament to be an aggressive bull down the road.
06:00Got my attention.
06:03It's okay.
06:07Despite being charged, Doug can't resist getting closer.
06:17I love living in Montana, and this is why.
06:21Got two bull elk sparring behind me.
06:25After shedding last year's rack, the bulls have spent just six months growing this season's antlers.
06:33Imagine the amount of resources that it takes to produce something like this.
06:37That would be like me producing another leg and wearing it around on my head.
06:42They'll shed this.
06:43They'll throw this away at the end of the season, and then they have to turn right around and start
06:47growing a whole other one again.
06:49The only way they can grow a bone this big, this fast, is to shunt the calcium, shunt the minerals
06:55away from the rest of the bones in their body.
06:57So they're literally pulling these things out of the rest of their skeleton and allocating it to the weapons.
07:03They actually go through a seasonal period of osteoporosis.
07:07The biggest bulls and bucks have brittle bones at exactly the time of the year when they're hurling themselves against
07:14each other in all-out battles.
07:17An antler can grow an extraordinary four centimeters a day.
07:21The amount of energy required is huge.
07:25Often by the end of the rut, bulls will have lost as much as a quarter of their body weight.
07:29They come out of that season starved and scratched and scarred and damaged,
07:34and they've only got a few short weeks to make up the calories that they've lost before winter, or they're
07:39not going to survive.
07:43Elk need to stay strong.
07:47The weakest are the most likely to become prey.
07:51So imagine the predators of these guys, something like a wolf.
07:56Wolves have to be fast, they have to be agile.
07:59Think about what would happen to a wolf if it had a set of antlers on the top of its
08:03head.
08:03A wolf that awkward wouldn't be fast enough to catch their prey.
08:07They wouldn't be able to turn quickly enough to catch their prey.
08:12But now if you turn around and you look at the elk, well, it doesn't make sense there either.
08:18I mean, elk have to be able to escape.
08:20They have to be able to be agile and to run fast,
08:23and antlers are going to slow them down just as much as it slows down a wolf.
08:28You might think that the primary function of an antler is to protect that elk from a wolf, but it's
08:33not.
08:33Even though a bull might be able to do some damage with its tines,
08:38it's not going to be enough to save it from predation.
08:47Considering what we know about the costs of these weapons,
08:50why would you ever want one?
08:52These structures are not helping the bulls survive.
08:59So what's the point of these extreme weapons?
09:04Survivorship isn't the only game in town.
09:06In fact, when it comes to evolution, the thing that matters the most is reproduction.
09:15Animals have evolved a multitude of weird and wonderful traits to help them seduce and mate.
09:25Tails.
09:29Noses.
09:31Even bottoms.
09:36All can be used to attract the opposite sex.
09:41This improves the chance that they will pass their genes on to the next generation.
09:48So how do extreme weapons increase an animal's ability to reproduce?
09:57For elk, antlers are worth the cost.
10:01The biggest bulls with the largest antlers tend to win the most fights.
10:08The winners mate with more females and produce the most offspring.
10:15For animals that bear arms, this is the evolutionary advantage extreme weapons provide.
10:28But arms races only occur in a relatively small number of species.
10:33So what are the conditions that spark them?
10:36Finding the answer isn't straightforward, particularly when many of your subjects can't be studied in a lab.
10:44For the kinds of things that we want to study, it's a little difficult to raise elk in captivity.
10:50We work on a much smaller critter.
10:53We work on beetles.
10:56In this particular species, the males have a horn that's like a pitchfork that sticks forward from the front of
11:02their heads.
11:02And in some of the specimens, these pitchforks can be almost as long as the whole rest of the body.
11:07This might look small relative to an elk, but I assure you, as far as insects are concerned, this is
11:13big.
11:13Every bit is impressive.
11:15It can be 30% of their body weight.
11:17That is literally like you or me wearing a coffee table around on the tops of our heads.
11:22So imagine doing everything you do from waking up in the morning to everything you do during a day with
11:28a coffee table fused to the top of your head.
11:31And now you've got a little taste of what it's like to be one of these beetles.
11:50Doug's fascination with biology began as a young boy.
11:56He travelled the world investigating all types of animal arms races.
12:03Slowly, he's been piecing together evidence to explain the evolution of extreme weapons.
12:12So there's an animal with an incredible weapon.
12:16There are different lineage of beetles from the ones that we study.
12:18These guys live in Chile, but their story is exactly the same.
12:22That is one of the biggest weapons of any living animal ever.
12:29They've got mouth parts or mandibles that have been elongated so that they have these curved, arcing pincers.
12:35The males grow up to nine centimeters long.
12:39Their specially adapted jaws can be half their body length.
12:45So the males are fighting battles with rival males.
12:47So these are two males sparring and facing off against each other, trying to fling each other from the tree.
13:13For the loser, it's a long way down.
13:19The battles between beetles offer the first clue to the special circumstances that trigger animal arms races.
13:28Beetles like this fight over wounds, sort of marks or nicks on the sides of a tree where sap will
13:34ooze out and drip down the side.
13:38The sap attracts females like this one.
13:41Unlike the males, she has small jaws.
13:45If you're a male and you can hold on to that real estate, you have opportunities to mate with the
13:50females when they come in to feed.
13:53It's not an accident that castles are located on the tops of hills or out on the ends of long
13:58moats and surrounded by water.
14:00We've known for centuries that things that are physically isolated or that have restricted access are much more economical to
14:07defend.
14:08Exactly the same logic applies to animals.
14:11The males that are able to win these battles or to hold on to that territory, I mean, the ultimate
14:16prize is reproduction.
14:22This male has fought off all his rivals, and now he's earned the opportunity to mate with a female.
14:32So when we start to look at these animals and say, what sets these species apart?
14:37Why do these particular species have such incredible weapons?
14:40The first clue, the first piece to the puzzle, is a defendable resource against which the fights can take place.
14:49So imagine things that whirl around in the water.
14:54Sometimes animals are fighting over resources that can't be defended.
15:02Think about things like raptors fighting in the air.
15:10They'll get into these big frenzied acrobatic mid-air snarls.
15:18In fights like that, things like agility or speed are likely to matter more than bulk and strength.
15:27For these kinds of fights, big weapons just aren't worth the price.
15:42A defendable resource is one of the critical requirements for an animal arms race to begin.
15:51And often, females are the resource.
15:59Male hippos use their enormous teeth in fights to guard harems of females from adversaries.
16:09Male white rhinos use their horns to protect territories that females travel through.
16:17And male elephants use their tusks in combat to defend fertile females from rivals.
16:25I love elephants.
16:35Each of those tusks can be like a hundred pounds of ivory.
16:39These are huge teeth.
16:42Bull elephant tusks are the biggest and heaviest teeth in nature.
17:01Oh, its tusk shattered.
17:04Okay, there you go.
17:05That's the impact that we're talking about here.
17:08Got the target.
17:15It's not very, very familiar.
17:19These are fantastic weapons, partly because they're lethal in their own right or able
17:23to stab, but they also allow these guys to push and strain against each other and size
17:27each other up.
17:29There's a deeper story behind the bull's tusks, one that's vital for all animal arms
17:34races.
17:37Bull elephants have these massive tusks, but if we want to understand the tusks, we actually
17:42have to look at the females.
17:44Female elephants also have tusks.
17:48Theirs are smaller, and not used for fighting in the same way as males.
17:54But it's the details of the female's reproductive cycle that explains the evolution of the male's
17:59bigger tusks.
18:02Female elephants are pregnant for 22 months, and after they give birth, they take care of
18:07their young for another two years.
18:11A female will only be fertile for five days out of every four years.
18:16That's an incredibly brief window of time.
18:19It's less than one half of one percent of a female's lifetime.
18:24So that means when you look across the landscape and you look at the male and female elephants
18:28out there, you're going to find that pretty much all of the bulls are ready to breed at
18:33any point in time.
18:35Every now and then, a female will become receptive, and when she goes into that window of fertility,
18:41every male in the landscape enters into the fray.
18:45Male elephants will travel for hundreds of miles to find a fertile female.
18:52Whenever there are more individuals of one sex able to breed than the other, the result
18:56is going to be competition.
19:00If you think of nearly any reproducing species, you'll find that the females are invariably
19:06unable to breed for long periods of time.
19:11Female mammals become pregnant.
19:15They provide milk and care for their offspring until independence, before reproducing again.
19:25After laying their eggs, female birds usually incubate and raise their chicks, before they
19:31can breed once more.
19:37The same trend is repeated in many animals.
19:49Males are almost always ready to breed.
19:54But reproductive females are rare, and this sets the stage for intense male rivalry.
20:03In all of these animals where you get these massive weapons, the males, the bulls, the bucks,
20:08they face fierce competition, and we think now that it's that second critical ingredient
20:13for an arms race.
20:26competition is the second condition needed for animals to evolve extreme weapons.
20:38But must it always be the males?
20:41Can competition ever cause females to evolve big weapons and fight?
20:52Thirty years ago, behavioral ecologist Stephen Emlin discovered a key piece of evidence to
20:58help answer this.
21:00I haven't seen this in a long time.
21:05He helped capture some remarkable film of an unusual tropical bird, the jacana.
21:12Sometimes, these are called Jesus Christ birds.
21:14They seemingly walk on water because the toes are so long they spread out their weight.
21:21Male jacanas are small.
21:23They incubate eggs in a nest and raise the chicks.
21:28Most females are bigger.
21:30She'll defend large territories where many males may live.
21:34Her only parental duty is to lay eggs in the male's nest.
21:40So, time-wise, the female, she's able to reproduce, in theory, about every ten days she could lay
21:46another clutch.
21:47He's stuck for almost three months, tending the eggs and the chicks.
21:51So the tables are turned and that means that females have to compete with each other for
21:55access to the males.
21:56Absolutely.
21:58Smart son.
22:01Stephen is Doug's father.
22:04He pioneered studies to show the effect of competition on weapon development.
22:10So, not only are the males doing the parental care, but it means the females are fighting
22:16over access to the males, and so the expectation is they should have larger weapons than males.
22:23These jacanas have a single sharp yellow spur on each wing.
22:28They're made of a tough, fingernail-like material called keratin.
22:33The female spurs can be 25% larger than the males.
22:40And for good reason.
22:41They use their spurs in battles to control access to breeding males.
22:47So, jacanas actually teach us a lot about the evolution of animal weapons.
22:52They show us that when the roles are reversed, then the weapons are backwards, too.
22:57Competition, in this case, is stronger in females.
22:59They're the ones with the bigger weapons.
23:02And in some jacanas, that role reversal has surprisingly cruel consequences.
23:08If a male is left alone, a new female will not hesitate to press her advantage.
23:16Claiming the territory, the lone male, and obliterating the previous female's unhatched chicks.
23:33And this is sort of a horrendous thing to think about.
23:36Basically, she is now destroying his eggs.
23:43Well, she wipes the slate clean.
23:45Exactly.
23:45So how much faster?
23:46If he's on eggs like that one, where she destroyed the eggs, she'd basically save herself two months.
23:51This brutal act means that the male is now available to breed and raise the new female's chicks.
23:58She gains a reproductive male.
24:01With his eggs destroyed, this male now has no choice but to mate with the female who killed his offspring.
24:10Jacanas may not have the biggest weapons, but they show that even when the roles of the sexes are reversed,
24:17if the conditions are right, an arms race can begin.
24:29Many animals compete intensely to defend resources, like a territory, food, or access to a mate.
24:48They engage in free-for-all brawls.
24:53Yet these species do not have extreme weapons.
24:57So something else, another condition, must be needed to kick-start their evolution.
25:08To find the answer, Doug turned to dung.
25:12More specifically, the beetles that depend on it.
25:15When you look at something like dung beetles, they're literally competing for the same piles of dung.
25:20And yet some of those beetles have these huge, spectacular weapons, and others have nothing at all.
25:26There's two kinds of dung beetles.
25:28There's a kind of dung beetle that carves the balls and rolls them away.
25:31Class one, the ball rollers.
25:35The ball rollers collect dung and move it to a safe place to raise their families.
25:41Sometimes there's a chaotic melee for control of a dung ball.
25:45But these ball rollers don't battle with weapons.
25:49They are unarmed.
25:52But then there's this other type of dung beetle that had been less well studied.
25:55And those are what we call the tunnelers.
25:59Significantly, the tunnelers have big horns.
26:02They don't roll the dung.
26:08Instead, they dig straight underneath it.
26:12So why have the tunnelers entered an arms race when their close cousins have not?
26:18Doug set up a viewing system to see what the tunnelers were doing beneath the surface.
26:23He had to use red lights to avoid disrupting their natural behavior.
26:28The missing piece to the story was what happened underground.
26:32Females dig tunnels beneath the piles of dung.
26:36Stashing it into these little brood balls, they're called.
26:38And then she'd lay an egg very carefully at the end of each one of these.
26:41The males plant themselves at the entrance to one of these tunnels.
26:46They've got hooks and spines on their legs that they can wedge into the soil.
26:50And they use their horns in fights with rival males.
26:53They face out.
26:54And any rival male that tries to get access to that female's got to push past the guarding male.
27:00And that's when fights break out.
27:04Until Doug captured this rare low-resolution footage 20 years ago,
27:08nobody even knew these beetles fought.
27:13The males use their shovel-like heads and sharp horns as weapons in brutal battles to control the female's brooding
27:19tunnels.
27:22These beetles will walk right by each other on the surface, not even bump each other.
27:27They could care less.
27:28But you put them in a tunnel and just like that, you've got to war.
27:32Any rival males have to enter one at a time and they pretty much have to face their opponent face
27:37to face.
27:40The difference between the two types of dung beetle was that the ball rollers fought in scrambles.
27:46Whilst the tunnelers, stuck in a confined space, were fighting in face to face battles.
27:54They were dueling.
28:00Doug wondered if one-on-one duels could be found in other species with extreme weapons.
28:07Chameleons have to be one of my favorite animals of all time.
28:18They are the quintessential ambush predator.
28:20So they sit tight, they can change the color of their skin.
28:23Their eyes can swivel in different directions so they move independently.
28:29And they have this fantastic ambush weapon.
28:32So they can slap out there with their tongue.
28:36A chameleon's tongue is able to extend like a telescope to twice the length of its body.
28:51It can accelerate from zero to sixty miles per hour in one hundredth of a second.
28:58But there's another kind of weapon in at least some chameleons.
29:01And it's this other kind of weapon that I get excited about.
29:05Even though all chameleons are closely related, only a few have big horns on their faces.
29:12So there is a set of weapons.
29:14These guys look like little dinosaurs, like a triceratops with the horns coming forward from the head.
29:20Male Jackson's chameleons use their horns to battle one another on branches over access to females.
29:26Think of this like Jurassic Park jousting as these males push and pry and try to twist each other off
29:32of the branch.
29:36So it turns out it's the details of the fight that matters.
29:41If you look at this fight, they're approaching each other face to face.
29:46They're locking horns, they're pushing, they're straining.
29:50Just like the tunneling beetles, the chameleons are duelling.
29:54It's no accident that for 5,000 years of recorded human history, the only sort of fight that has ever
30:01mattered for honor or status was the duel.
30:05Ritualized, repeatable, and fair.
30:07When males face off one-on-one in a duel, males with bigger weapons win.
30:18So this was that final ingredient.
30:21The third, the missing ingredient, was duels.
30:26Doug's discovery was the final piece of the evolutionary jigsaw.
30:31Fights must be a face-to-face duel.
30:40Only when animals fight in these ritualized duels do the benefits of extreme weapons outweigh the costs.
30:55What I'm suggesting is that when these three conditions are met, intense competition, defendable resources, and duels,
31:03selection for big weapons becomes so strong that it eclipses any costs associated with these structures.
31:09Nothing else matters.
31:14Launching their populations onto trajectories of explosive weapon evolution.
31:21Most forms of life on Earth do not have extreme weapons.
31:28The rare species that do come from a diverse range of different animal families.
31:35Doug's theory describes three simple conditions that unite them all.
31:42A resource that's defendable.
31:46Competition with a rival.
31:48And fights that take place as one-on-one duels.
31:55And in the animal kingdom, when those three conditions are present,
32:01extreme weapons can evolve.
32:19But there are sometimes exceptions to rules.
32:27The most iconic example
32:31is an ancient extinct beast.
32:42We're looking at a fossil of a saber-toothed cat.
32:44This is the actual fossil. It's not a cast.
32:47And the animal probably lived in California about a million years ago.
32:53Saber-tooths actually teach us an awful lot about animal weapons.
32:57For one thing, you can't miss the teeth, right?
32:59I mean, the teeth are huge.
33:00But that's actually an interesting problem in and of itself.
33:03Because this is a predator.
33:07The primary use for a saber-tooth's colossal canines is thought to be for hunting,
33:11not securing a mate.
33:17This is why saber-tooth's are so exciting. They're the exception.
33:22It's the manner in which they caught their prey that explains why they evolved extreme weapons.
33:28Saber-tooth's are special because they're ambush predators.
33:35Imagine what it would be like to get chomped on by something like that.
33:41They sit and wait and then lunge out with a quick strike to grab unsuspecting prey.
33:47For most predators, heavy armories are simply too bulky.
33:52They'd slow them down.
33:57But for ambush predators that strike quickly, the evolution of big weaponry makes sense.
34:11It works under the ocean for things like mantis shrimp and pistil shrimp.
34:17It works for antlions.
34:22It works even for those crazy deep-sea anglerfish that are essentially a big jaw with a tail.
34:28These guys had lures that they would dangle in front of them that would pull the prey into them.
34:33Ambush predators use their extreme weapons to capture and kill their prey.
34:40But the majority of animals which have entered an arms race aren't hunters.
34:46All of the rest of the species with big weapons, species with the biggest and the craziest things sticking off
34:52of their bodies,
34:53those animals are using their weapons for reproduction.
34:58These creatures use their weapons to fight each other.
35:03You might imagine that their epic clashes result in many lethal injuries.
35:14But animals with extreme weapons use them in a manner that means win or lose.
35:19The likelihood is that you will survive the fight.
35:26The very nature of a duel means that there are rules of engagement.
35:31These species fight head-to-head, weapon-to-weapon, which means they're less likely to be fatally gouged or gored
35:39to death.
35:44For the ultimate test of this principle, Doug is travelling to Washington State.
35:57He's come to see the animal weapons record holder.
36:04All right, Brooke, can I see the biggest weapon in the animal world?
36:08Sure.
36:12Here it is.
36:13That's it?
36:14It's not very big.
36:16So these are fiddler crabs.
36:18Ow!
36:19Maybe it's a little bit bigger than I thought.
36:22So this is it.
36:24The record holder.
36:27So it may be a small crab, but this claw, the weapon, can be half of its body mass.
36:33So the claw can weigh as much as the whole rest of the crab.
36:35It'd be like you walking around carrying my whole body weight as one of your arms.
36:40That's incredible.
36:42Fiddler crab claws are proportionally bigger than any other known animal weapon on Earth.
36:48There's about 103 different species of fiddler crabs.
36:51They live all over the world in the tropics and they eat algae off the surface of the mud.
36:58Brooke Swanson investigates the surprising advantages of these super weapons at his fiddler crab lab.
37:05So females have two little claws and they can actually eat twice as fast as the males.
37:11The males, only, have these giant claws.
37:17And can't use their weapon claw to eat.
37:21Alright, so he's bitten me three times already.
37:23Can you show me what these guys can do?
37:25Absolutely.
37:26We can use this force meter to measure how strong their claws are.
37:31This just measures how hard they squeeze.
37:33Exactly.
37:34You put their claw right there.
37:38There you go.
37:38They squeeze.
37:40That's about 20 newtons.
37:42So the crab is producing about 20 newtons with its claw.
37:45Five pounds of force.
37:47So like having a bag of sugar on a pin pushing on you.
37:52So it's not just five pounds, it's five pounds concentrated on a very sharp point.
37:56Exactly.
37:57That's why it hurts so much.
38:00Crab claws have enough power to slice straight through a rival's shell.
38:06So they're plenty strong enough to kill each other.
38:10But when we keep them in the lab, we hardly ever see them fighting.
38:13And I've never seen one kill another one in the lab.
38:16And when you study these in the field, it's very rare to see them fighting there as well.
38:22So if they hardly ever use their giant claws to fight, what do the male crabs use them for?
38:29So here we have two male fiddler crabs.
38:32And their body size is about the same.
38:35But if you look at their claws...
38:37It's huge.
38:37...the claws twice as big as the other one.
38:40Wow, that is so obvious.
38:41What they spend most of their time doing is not fighting with these claws, but waving them in the air.
38:48So they walk around on the sand and they wave the claw and wave the claw and wave the claw.
38:54And they're signaling to the other crabs how big and how strong they are.
39:00And so if you're looking at crabs by their claws, you can easily tell the difference.
39:05You can easily tell that this crab is bigger and stronger and a better fighter.
39:09And that's what makes the claw a good signal.
39:12This is awesome. This is just like what we see in other animals.
39:15You'd think that the species with the really big weapons would use them to fight all the time.
39:18And yet, what we see is the reverse.
39:20That the species with the biggest weapons are actually the most peaceful.
39:30Paradoxically, it is uncommon for most animals with extreme weapons to fight.
39:37Although we revel in the rare moments these creatures do clash.
39:42In the natural world, confrontations seldom escalate into head-to-head brute force combat.
39:51When rival males meet, they will often avoid fighting by measuring the prowess of their opponent using ritualized behaviors.
40:01Elk males do this by strutting in parallel lines to assess the competition.
40:12Nearly all these encounters end without a single blow being dealt.
40:22So we've gone from what was essentially a blunt force weapon to something that we now realize is a whole
40:28lot more than that.
40:30The rival males are backing away without even challenging them in open battle.
40:35These biggest weapons of all are acting as a deterrent, settling dangerous contests without actual battle.
40:42These fiddler crabs have a weapon so deadly that attacking an equally armed adversary could be suicidal.
40:52In the animal kingdom, the most powerful weapons are also the most effective deterrents.
41:05So I've been to some amazing places in my search for extreme animal weapons.
41:10The place I'm going now is the strangest of all.
41:13The weapons we're going to look at today are both exciting and terrifying.
41:19Doug has long wondered if what applies to the animal arms race can be applied to our own.
41:35Ross Millard is a captain at Malmstrom Air Force Base in Montana.
41:55Can you tell me about the base?
41:57Absolutely. We're here at Malmstrom Air Force Base.
42:00We are one of three missile bases in Air Force Global Strike Command.
42:03Our ultimate weapon here is the Minuteman III nuclear missile.
42:06The big one? Yes.
42:07The Minuteman III is an intercontinental ballistic missile that can be armed with a nuclear warhead.
42:15These are the most destructive weapons on Earth.
42:19So what can you tell me about the capability of these missiles?
42:23The missile itself will take the warhead 7,000 miles and produce a nuclear detonation.
42:31Other than that, I can't get into great detail on the power of the weapon, the specific characteristics.
42:38But it's powerful.
42:39Yes. And not just powerful, but designed and intended to work.
42:43There are 150 of these missiles ready to launch from bunkers in the 13,000 square miles surrounding the base.
42:52Captain Millard is taking Doug to the missile launch training facility.
42:57So they're actually at different depths. Some of them are a little more shallow, just depending on the topography and
43:04the terrain.
43:10I can't believe I'm in here.
43:14From protected subterranean control centers, missileers can fire the nuclear warheads.
43:20All right. So what does this console do?
43:23Well, essentially, it allows the crew members to be able to exercise command over all the missiles that are assigned
43:28to them.
43:28So each control center is responsible for 10 missiles on this screen or on the far right-hand screen over
43:34there.
43:35So what would you say the primary function of these weapons is?
43:38So day-to-day, the primary function is to provide a deterrence factor to let our adversaries know that we
43:43have this capability.
43:45But it's an interesting paradox with the system because we don't want to use it.
43:49But if we have to use it, we have to know that it works as well, too.
43:51It's exactly the same in animals. They do almost exactly the same thing.
43:54So you find that the biggest, the craziest, the most extreme animal weapons always work as deterrence, too.
44:01If you're a male with the smaller weapons, it often pays just to assess the situation and turn around and
44:06walk away.
44:10All extreme weapons work as deterrence.
44:16And the similarities do not end there.
44:19So one of the other parallels that we see with animals is that when the weapons get really, really big,
44:25then only a few individuals in the population can afford them.
44:30Realistically, how many countries could possibly afford to have the infrastructure, the capabilities that we're talking about with a nuclear
44:38deterrence triad?
44:39Very few. It's not that simple. Essentially, it's just because you have the missile and there's all sorts of infrastructure.
44:44There's the warhead, there's the support equipment, and there's all sorts of various increments along the way that add to
44:50the complexity.
44:51The whole nuclear enterprise is much more expensive than just one missile.
44:56The costs associated with owning these weapons is phenomenal.
45:02Of all the nations in the world, only nine are thought to control nuclear warheads.
45:09I just have to say again that that is exactly the same as what we see in animals.
45:12It's exactly the same. The reason the really big weapons work in the animals is that they're so unbelievably expensive
45:18that almost nobody can afford them.
45:20I mean, that's part of why they work as a deterrent.
45:22It's the best condition, the biggest bulls and bucks. Those are the only animals that can afford the really big
45:27weapons.
45:30Captain Millard has agreed to show Doug a launch sequence.
45:33So we will launch the missiles, but the person who has the authority is the president.
45:38So up in this container here, yep, that one right there, if you open it up, so there's going to
45:43be a key in there as well as authenticators.
45:46For Doug, there are parallels between the development of our own superweapons and the evolution of the biggest weapons in
45:52nature.
45:55So manufactured weapons aren't parts of our bodies like tusks or horns.
46:00And instructions for their construction aren't encoded in DNA.
46:04But their forms change through time in much the same way as animal weapons.
46:09And we'll go ahead and slide down.
46:13When the conditions are just right, manufactured weapons can get caught up in arms races too.
46:19I'll insert the launch key and on my count we'll turn and hold.
46:23Surging forward to bigger and bigger sizes.
46:26Deadlier, faster and vastly more expensive.
46:30Three, two, one, turn, hold, and release.
46:48If Doug's theory is right, all extreme weapons, human or animal, evolve over time under the same conditions.
46:57They cost an enormous amount of resources.
47:00And their primary function is as a deterrent.
47:10So is there anything that can undermine the animals with the most extreme weapons?
47:18Doug was studying dung beetles when he discovered that the smaller males without the largest weapons had found a sneaky
47:24way to reproduce.
47:28So one of the things that we were able to learn from these beetles is that the little beetles cheat.
47:35Doug already knew that males with big weapons guard the entrances to female tunnels.
47:40If you're another big beetle, you can challenge him in outright open battle.
47:44But if you're tiny, you don't stand a chance.
47:48So instead of fighting a losing battle, they go right next to a tunnel and they start to dig their
47:53own tunnel.
47:55They mine their way into the tunnel, come in beneath the guarding male, go straight down to the female,
48:00kind the female, mate with the female, turn around and lead.
48:05This small, sneaky male has found a way to evade the guard and mate with the prized female.
48:13Then he escapes up his own secret tunnel.
48:17Big males have the weapons, the big males fight the conventional battles.
48:21The little guys break the rules.
48:24The same cunning tactics can be seen in other species.
48:31So consider the cuttlefish.
48:35In cuttlefish, you get all these little tiny males.
48:37I mean, these wimpy, tiny runts.
48:39There's no way they would win if they tried to fight by the rules.
48:45Big, dominant males guard fertile females.
48:50If an evenly matched contender challenges him,
48:53occasionally they battle one another with sharp beaks and tentacles.
48:58I would not want to get caught up in a tango with one of these guys.
49:02The winners hover above the females they want to mate with.
49:06So now we've got another cuttlefish coming up.
49:09This one looks like a female.
49:12But it's not a female.
49:14If you look closely, this is actually a tiny male.
49:18But he's ploked himself in colors that make him look like a female.
49:22So he can come right up to the guarding male unmolested.
49:28The sneaky male works his way right on in there and by looking and acting like a female,
49:34he's able to get into a position where he can breed with the female too.
49:40This female's eggs will be a mix of some massive macho males and some tiny tricksters.
49:56These tactics are so pervasive that Doug can even find cheats in Montana.
50:03Jack Hogg is a bighorn sheep biologist.
50:07He's taking Doug to search an island on Flathead Lake to observe their alternative tactics.
50:21Bighorn sheep are famous for engaging in epic ritualized battles.
50:28During the rut, rival males size each other up.
50:36Occasionally, when it's an even match, they fight.
50:48Through a series of horn-to-horn clashes, the rams establish a hierarchy.
50:55The winners become the dominant males.
51:04During the breeding season, the victors guard fertile females.
51:10Largest-horned, largest-bodied rams search for and defend ewes during their fertile period.
51:17So the biggest males with the biggest weapons, their strategy is to guard access to the females for that one
51:24day when they're fertile.
51:26Jack's discovered that the subordinate males have their own cunning mating strategy.
51:31He calls it coursing.
51:34The coursing strategy, in essence, is to do whatever it takes to evade the defense of a socially dominant ram
51:42who's defending a female during her fertile period.
51:45But it's whatever needs to be done, whatever dirty trick, to force a mating.
51:53The dominant male here is called Crudhorn.
51:59He's guarding a fertile female.
52:04The fertile female has a white spot, so we're calling her white neck.
52:15A large group of subordinate males are watching white necks every move.
52:22They want to mate with her, but Crudhorn is guarding her closely.
52:29So Crudhorn has two important tasks in front of him.
52:33One is to mate with her during her fertile period.
52:36But he also has to defend the female against any male who wishes to breed with her.
52:48Typically females run away from this group of large bodies that are interacting.
52:53It's a dangerous place to be, so they run away, and that's what creates the chase.
53:17Whitenack wants to escape the rush of coursing males.
53:24Crudhorn is trying to keep up with her.
53:27And deflect the subordinate males during the chase.
53:34Crudhorn's defence actually is extraordinary. It's very good.
53:39He's very physical in terms of clashing and pushing and shoving the other rams.
53:45But every once in a while, one of these coursers will succeed in forcing the breeding.
54:00One coursing male attempts to mate with Whitenack while she's separated from Crudhorn in the scramble.
54:05That's all it takes is a few seconds.
54:07A few seconds.
54:08The coursing male now could have a chance of fathering Whitenack's offspring.
54:18By trying to mate with the female while running, even for just a mere moment, the coursing male has used
54:24a tactic unrelated to the size of his weapons.
54:28Because it's clever in a way. It's almost like they're able to use the bulk and the weight and the
54:33size of the weapons of the alpha males against them.
54:38By getting them to lunge in a particular direction and then taking advantage of being smaller and agile.
54:44So if all these males are using these alternative strategies, is it even worth being the big alpha male?
54:50They do better. They have more babies, basically.
54:53A high ranking male, he would be the father of 60% of the lambs produced by the females he
55:00defends.
55:01The dominant male, the male with the biggest horns, still fathers far more offspring than all of the coursing males
55:08combined.
55:12To the victor go the spoils. We see this in every one of these animal systems.
55:16The biggest males are the ones that can afford to produce the biggest weapons.
55:21And these males win in every sense of the word.
55:28Today, perhaps the biggest risk for many animals with extreme weapons doesn't come from cheats.
55:36It comes from a much more modern threat.
55:41Weapon sizes in some populations of animals, including bighorn sheep, elephants and caribou, are decreasing.
55:53And the trigger for this change is us.
56:00Human trophy hunters prize the biggest tusks, horns and antlers.
56:09Trophy hunting removes the genes for the biggest weapons.
56:15In one elephant population, the average tusk size was reduced by 40% in just 25 years.
56:25And in another population, the number of tuskless individuals increased by over 20%.
56:34We have chipped the balance of these animal arms races.
56:47Despite the human hunters,
56:50enormous biological costs and being sabotaged by cheats.
56:57For animals in an arms race,
56:59the males with the biggest and most extreme weapons are the most successful.
57:07These individuals are winning the evolutionary war.
57:11They are not wiping themselves out.
57:19And maybe that's a vital lesson for us.
57:37So this has been quite a journey for me.
57:39A ride more wild than I ever could have imagined.
57:43So although most animal species don't have big weapons,
57:46these extremes have arisen many different times independently within separate lineages of animals.
57:57What's the same though,
57:59are the conditions that are necessary in order to launch that population into an arms race.
58:08Who'd have thought that the battles of beetles held lessons for weapons everywhere?
58:14Extreme weapons are extreme weapons.
58:16Animal, human, it does not matter.
58:18Their biology is exactly the same.
58:29Travelling Berlin to Stuttgart,
58:31Michael Portillo in Great Continental Railway journeys is now at six.
58:36And next, there's stuff to be sorted and sold in Floggett.
58:50A 착han in Great Continental Railway
58:52You
Comments