10 Bizarre Ways to Avoid Being Dinner


Here’s a protip: If you’re an animal in
the wild, try not becoming someone else’s dinner. You’ll survive longer and have a better
chance of passing on your genes. You could blend in with the background, or
disguise yourself as something unappetizing … like a pile of poop! Or you could do the opposite, and have garish
colors to let predators know you’re toxic. There’s safety in numbers, so maybe some
stranger will be eaten instead of you. Or try waking up after your predators have
gone to sleep. All kinds of antipredator adaptations have
evolved across the animal kingdom, from physical features to behaviors. And some animals use pretty bizarre strategies
to stay safe. [INTRO] [1. Assassin bugs] or [1. Assassin bugs and their camo meat-shield] Assassin bugs are named for their predatory
skills, but they’re actually somewhere in the middle of the food chain. So there’s a species of assassin bug that
avoids the wrath of its predators by wearing the corpses of its prey! This bug is mostly an ant-killer, using sharp
straw-like mouthparts to dissolve the tissue and suck out those nutritious juices. But instead of tossing the leftover exoskeletons,
the assassin bug sticks them together with tiny threads and stacks them on its back. Now, one of its predators is jumping spiders,
which rely on their eyesight for hunting. And a 2007 study showed that jumping spiders
are around 10 times less likely to attack corpse-laden assassin bugs than bare-backed
ones. Researchers think the ant-corpse backpack
changes the bug’s outline and movement – so predators that depend on vision just can’t
tell that it’s food. Or if they did attack, they might just get
a heaping mouthful of ant corpses as the assassin bug scurries away … which doesn’t sound
all that delicious. [2. Moths] or [2. Moths vs. bats: warning, jamming, and dropping
out of the sky] Instead of sight, bats hunt using sound, also
known as echolocation. Basically, they call into the night at frequencies
higher than we humans can hear. The audio signals that bounce back let the
bat know what’s around: trees, buildings, or maybe a tasty moth. Moths may seem like an easy meal, but that
doesn’t mean they’re defenseless against their flying foes. Some, like the greater wax moth, have evolved
the ability to detect high-pitched sounds, like bat echolocation clicks. If they sense a bat getting too close, they
might fly in wild patterns, or even drop out of the sky to avoid being caught. Other moths take it further and emit clicks
of their own to freak the bats out, or tell them, “I’m not tasty, don’t eat me!” Plus, a few species of tiger moth can even
use their clicks to interfere with the bat’s echolocation, a process called jamming. Rather than detecting a clear “moth” audio
pattern, the bat gets a garbled signal – and can lose track of the moth in its confusion. [3. California ground squirrels] or [3. The California ground squirrel’s ‘hot-tail’] California ground squirrel moms also have
a few tricks up their tails to keep their young safe from hungry predators. First off, they’re tough and willing to
fight – with sharp teeth and claws, and have even evolved resistance to rattlesnake
venom. So lots of predators take heed of her warning
signals. If it’s a mammal like a fox or badger, she’ll
call loudly. Basically saying, “I’ve seen you. You better stay away.” But predators like snakes probably don’t
hear airborne sounds as clearly, or even at all, so shouting would be a waste of energy. Instead, she uses tail-flagging: waving her
bushy tail to tell them to back off. But that’s not all: some rattlesnakes have
heat-sensing organs that detect infrared energy. If one of these rattlesnakes is prowling around,
California ground squirrels heat up their tails while tail-flagging – probably through
increased blood flow. When the rattlesnakes get the message, their
behavior changes dramatically, from predatory to defensive. Researchers think this hot-tail action is
a special adaptation, because the squirrels only use it with rattlesnakes – not gopher
snakes, which can’t sense infrared. So evolution has given these mammals a bunch
of strategies to help future generations survive. [4. Bombardier beetles] or [4. The boiling acid of bombardier beetles] Bombardier beetles aren’t the most graceful
things. They’re bulky, and even though they can
fly, it takes a while to get airborne. But if one feels threatened, it can buy itself
some time … with raw pain! Tilting its back end towards its aggressor,
the beetle fires explosive pulses of boiling hot, toxic liquid. The beetle’s abdomen contains two separate
chambers, storing hydroquinones and hydrogen peroxide respectively. These react violently into a hot, high-pressure
spray of benzoquinones: chemical irritants that deter virtually all predators. Researchers from MIT have been studying this
superpower. They used synchrotron X-ray imaging to see
inside the beetle as it detonates. The flexible membranes and valves they discovered
were complex, but they were only a few evolutionary tweaks away from the beetle’s much-less-violent
relatives. Understanding how this insect creates and
survives these intense chemical sprays could even help engineers develop beetle-inspired
propulsion and blast-protection systems. [5. Black-capped chickadees] or [5. Black-capped chickadee call signs] Next up are black-capped chickadees. They’re common North American birds, and
tasty treats for many birds of prey, also known as raptors. But these little songbirds have surprisingly
complex ways of communicating, with special calls that trigger fight or flight reactions. If a chickadee spots a soaring raptor, ready
to snatch a meal, it’ll use a soft, high-pitched “seet” call. This works like an urgent whisper: “get
down now!” But a less immediate threat, like a perched
raptor, is signalled by the famous “chick-a-dee” call, which can be a call-to-arms. The call rallies the whole flock, and even—
sometimes other species, to mob and pester the raptor. With its cover blown, the predator’s best
bet is to try elsewhere. Researchers think that chick-a-dee calls could
encode some detail about the predator, as well. The more “dee” syllables, the bigger the
threat level – and up to 23 “dees” have been recorded! [6. Triggerfish] or [6. Triggerfish lockdown with a fin] The colorful, kind of goofy-looking triggerfish
are found in warm ocean waters around the world, and play it safer than some of these
other animals. They search the ocean floor for food, like
molluscs and crustaceans. But if threatened, they’ll head for the
nearest cubbyhole to hide. See, triggerfish have two spiny dorsal fins
that normally lie flat against their body. If they’re wedged in a crevice, they can
lock these spines upright to stay in place. That way, it’s a lot harder for predators
like tuna and dolphinfish to pull them out and swallow them. The “trigger” is a shorter, wedge-shaped
spine that controls the longer, main spine. Pressing the trigger down is the only thing
that’ll flatten the dorsal fin, but predatory fish can’t really get to it, or even know
that’s where the release-mechanism is. A triggerfish does have muscular control over
this trigger spine, though, and can flatten its fins again when it feels safe enough to
leave its crevice. [7. Boxer crabs] or [7. A crab with anemone boxing gloves] Crabs use their claws for all kinds of things:
grasping food, nipping an enemy, or even attracting a mate. But boxer crabs, also known as pom-pom crabs,
use theirs for brandishing weapons … by dual-wielding stinging anemones! Like tiny toxic boxing gloves! Boxer crabs and different anemone species
have evolved symbiotic relationships. The candy-striped crabs get protection from
predators, usually small fish, who don’t want a face-full of stinging tentacles. In return, the sea anemones get a mobile bodyguard
24/7, and pick up leftover food scraps dropped by the crab. So it sounds like a pretty good deal, but
this relationship might not be as mutually-beneficial as it seems. A 2013 study found that boxer crabs only let
their anemones feed for short amounts of times , stealing the rest of the food for themselves. This keeps the anemones way smaller than they
would be if they just grew on the seafloor – almost like portable bonsai. So even though this relationship looks kind
of cute, it’s actually more of a one-sided, parasitic deal. [8. Hagfish] or [8. Slime and twist with the hagfish] Hagfish, on the other hand, look about an
unappealing as their name suggests. Their antipredator defense is pretty gross,
too. If startled or grabbed by a predator like
a shark, a hagfish will spew out a bunch of goopy slime from pores all over its body. The slime is made from mucins and other thread-like
proteins that expand in water, creating a thick gel that gets everywhere! Beyond just being gross, this mucus is potentially
lethal. It’s not toxic, but it can clog the gills
of attacking fish, probably by keeping water from flowing as easily. All of a sudden, the predator has to focus
on not suffocating to death, rather than finishing its lunch. Plus, to make a speedy exit, hagfish can twist
their flexible bodies into an “overhand knot” shape to wipe off the mucus layer
and slip away. Hagfish slime is an area of active research,
as scientists try and figure out how the massively long protein fibers in the slime are stored
and deployed. One lab is even talking about threading similar
proteins into tough, stretchy clothing of the future! [9. Thomson’s gazelle] or [9. Pronking – Thomson’s gazelle] Pronking, or stotting, may sound like some
new internet fad, but it’s a move with a message that keeps some animals alive. In the African plains, herbivores like the
Thomson’s gazelle tend to hang out in herds, keeping multiple eyes on the lookout for predators,
like big cat species. So, as a gazelle, you may have some safety
in numbers, but you still want to make sure the predator isn’t going for you. Predators don’t want to waste precious energy
on a failed hunt, so many of them choose their target carefully – maybe a weaker-looking
gazelle. So, some prey animals pronk! Basically, it’s a high leap in the air with
an arched back, and all four legs straightened out. It might seem like a wasteful, energy-intensive
activity, but some researchers think that’s the point. Pronking could show that a gazelle has strength
to spare, and predators had better pick someone else for their dinner. [10. Ground beetle larvae] or [10. Ground beetle larvae vs amphibians: become
the predator!] In many cases, the food chain is pretty well-defined:
Like how lions eat zebra, how spiders eat flies, or how many amphibians eat ground beetle
larvae. Well, most of the time. Once in a rare while, there’s an evolutionary
role reversal. Introducing the Epomis larva: when prey becomes
predator! The lone larva acts all innocent and helpless,
wriggling around to entice the would-be predators. For any other ground beetle larva, the high-speed
lunge from a hungry frog would mean game-over. But Epomis larvae are ready and waiting: With
a sudden head flick, the grub dodges the frog’s attack and strikes back. It latches on to the frog’s body with its
tough jaws and starts to chow down, sucking out fluids and eventually eating away at the
soft froggy flesh. We’re not exactly sure how this switcheroo
evolved, but when scientists conducted nearly 400 Epomis larva versus amphibian battles-to-the-death,
the grub won every single time. So however these ground beetle larvae managed
it, it’s working well for them now! The animal kingdom can be pretty brutal, because
everyone’s just trying to eat and stay alive. But evolution keeps things interesting, especially
with all the creative adaptations in prey animals – from hiding, to making a scene,
to really putting up a fight. Thanks for watching this SciShow List Show,
and thanks especially to all of our patrons on Patreon who make this show possible. If you want to help us keep making videos
like this, just go to patreon.com/scishow. And don’t forget to go to youtube.com/scishow
and subscribe!

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Comments

  1. 1:47 – EVOLVED the ability to detect high-pitched sounds.
    And you call your channel a SCIENCE show!?
    And there are people still believe in this shit, and think they are smart!
    All your channel is "we BELIEVE that…", "we THINK that", "we ARE NOT SURE, but", "we DON'T KNOW for sure" …

  2. so glad I'm a human who can just go to the supermarket for food

    wouldn't want to have to fight someone to death just to get food

  3. Beetles and Larvae are two separate forms of the same frog eating behavior. http://blogs.discovermagazine.com/notrocketscience/2011/09/21/beetle-larva-lures-and-kills-frogs-while-the-adult-hunts-and-paralyses-them/#.WAwbNSSHNQ8

  4. What's never been explained to me is how the 'evolved x defense' thing works. So we have a defenseless Frog A see defenseless Frog B get eaten. Defenseless Frog A's genes then somehow decide to develop a upgrade to the next generation via poison on the skin? Or spines? Or a shell? How did today's species' ancestors survive long enough to breed without these defenses? It seems like the time-frames evolution theory works with would not allow for a defenseless species to survive an environment of predators before going extinct.

  5. "Here's a pro-tip, if you're an animal in the wild, try not becoming someone else's dinner. You'll survive longer and have a better chance of passing on your genes"
    Oh! That's what I've been doing wrong!

  6. Some species of plankton light up whenever they come in contact with anything not water. this is so that small fish will not eat them, as the small fish will be lit up by the plankton and eaten themselves. Quite a good strategy in my opinion.

  7. All squirrels flag when they see a potential predator. This automatically puts rattlesnakes on the defensive. They know they've been seen and that their would-be prey is capable of defending itself, so they back off and try to slink away. They also know that turning their back on the squirrel can get them attacked as they retreat, so they keep their heads up and threaten to strike if the squirrel doesn't allow them to leave in peace.

  8. they're teaching us to avoid being someones dinner, but they forgot about us being someones breakfast or lunch, probably a snack

  9. Just for reference, hydrogen peroxide has also been used as an oxidizer in rockets. And the principle is similar. 😉

  10. The ground beetle larvae are one mean piece of meanness. Imagine you trying to bite in a steak and it suddenly jumps on your head and goes full Alien-Hand-Monster

  11. SciShow, I have a question that I can't find anywhere on the internet or in books, or anywhere really. How can I hear a bat's echolocation when so many scientists say it is beyond the range of human hearing? No one else I know can, and I have proven that I can because when out I will say, "I hear bats" and then we will all see them fly overhead.  
    Also, I have to say, the people on forums who claim to be able to hear do not describe it the way I hear it.
    They describe it more as a squeak whereas I describe it more as a series of repeating, high pitched, waves that pulsate. Maybe not the best description, but it's difficult to describe really…

    Thanks. Peace.

  12. The edit with delay between the sentences is very weird and disconcerting… and once noticed cannot be unheard. The entire video sounds quite frenetic because of this.

  13. EU PRECISO DORMIR, TO MORRENDO DE SONO
    VIM PRA BIBLIOTECA DA FACUL TIRAR UM COCHILO NO SOFÁ
    MAS TEM UMA MULHER FILHA DA PUTA QUE NÃO SAI DE LÁ
    VAGABUNDA DE MERDA, TEM UMA VIDA INTEIRA PRA IR NO SOFÁ E ESCOLHE DORMIR AQUI JUSTO HOJE??? AH EU NÃO MEREÇO

  14. FROG BUG WARS!

    On the blue corner! The Challenger! MR! FROG! (0/0/0)

    On the red corner! The undisputed. Undefeated! The Epomis Larva (399/0/0)

    FIEEEEEE~GHT!

  15. About the beetle v.s frog.. Because frogs are faster then beetles and and obviously jump farther, if the frog is given a area about 1,000 times of that of a 10 gallon bucket I bet the frog would win At least 50% of the time.

  16. I don't remember ever hearing people pronounce "anemone" correctly. Somehow it always turns into "ananomy" or even "an enemy". I'm not surprised anymore, I don't even feel annoyed, but it still boggles my mind.

  17. Bats do make sounds we can hear. Iv heard the clicks. I might not be able to hear the full range of sounds but bats echolocation makes sound and humans can hear it so facts are relative. Disappointing i know. Facts are a joke. We just pick out the facts we wana find out and ditch the rest in the minority box.

  18. They killed 400 frogs just to be certain the bug couldnt lose. Is it just me or do 80 percent of the feral humans on the earth care so little for the suffering of other species to the point where they mise well be prisoners under the knife a hundred years ago. Did you know humams rip the fur off bunnies alive with no anesthesic. You would not say only humans can suffer when you hear the rabbits screaming. The human race is disgusting and should be ended now.

  19. something can only be attacked so many times before the dance becomes too predictable & the arms race takes a diametric opposite twist.

  20. Hey Sci show. Why do House Cats & Foxes & Reptiles have elliptical irises: while Big Cats, Birds, Dogs & We have circular iris/pupils; also, does it make much difference? I've always admired elliptical pupils and noticed the familiar ties while species don't share the adaptation.

  21. Assassin bugs and wheel bugs can have some devastatingly painful and venomous bites. Not lethal, but they inject those digestive juices into YOU if they feel threatened. And they spread Chagas disease. Fun

  22. hey fellow chickadee players theres a threat in b12 of the northeastern forest its a threat level of 30 dees and i need backup to mob this thing

  23. I think its cool to learn how great that beetle is but was it really necessary to go through all the way to the death of frogs…I mean jeeze after watching 3 of them go out like this I would feel unclean.

  24. The ground squirrel also makes a paste out of the snake skins to rub in their tale so the scent of the snake is emitted when the wave it around & warm it up…

  25. "Avoid getting eaten to pass along your genes" Unless you're one of the several species (namely some spiders, praying mantises, etc) whose males feed themselves to the females to ensure they stay busy enough to Get Busy.

  26. (6:18) Hagfish also make a sloppy mess of Oregon roads when the truck transporting them loses control, dumping lots of them across the highway, shutting it down for hours. Yes, this has actually happened, causing drivers to backtrack to out-of-the-way alternate routes.

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