In the deserts of the American Southwest, spadefoot toad tadpoles
hatch in tiny oases. Until they develop into toadlets,
they can’t survive outside of water, but these ponds are transient
and quickly evaporate. The tadpoles are
in a race against the clock to grow up before
their nurseries disappear. So nearly overnight,
some of the brood explode in size. They use their jack-o-lantern teeth
and huge jaw muscles to devour their smaller pond mates. Nourished by this extra fuel, they develop quicker,
leaving the pond before it can dry out. The spadefoot toad
is far from the only animal to eat members of its own species
as a normal part of its life cycle. All of these animals do. If that surprises you,
you’re in good company. Until recently, scientists
thought cannibalism was a rare response to starvation
or other extreme stress. Well-known cannibals, like the praying mantis
and black widow spider, were considered bizarre exceptions. But now, we know they more
or less represent the rule. While it may seem counterproductive for members of the same species
to eat each other, cannibalism can promote the survival
of the species as a whole by reducing competition, culling the weak, and bolstering the strong. Some species, like the spadefoot toad, cannibalize in response
to environmental pressures. Their situation is precarious, but cannibalism for them isn’t
a last-ditch attempt to avoid starvation. Rather, it’s a way to more quickly
outgrow a stage where they’re especially vulnerable
to predation or dangerous environmental conditions. Other species, including many fish, indiscriminately cannibalize each other
during foraging behavior. Fish produce large numbers of tiny young, and adults exhibit about as much
individual recognition of their offspring as humans do for a handful of raisins. Fish eggs, larvae, and juveniles
are easily available, nutrient-rich meals, and with thousands of eggs in a clutch, plenty are still available to hatch
after the adults have snacked. Baby fish aren’t just at risk of being
cannibalized by adults— siblings eat each other too. Sand tiger shark eggs develop and hatch inside their mother’s oviducts
at different times. When the hatchlings run out of yolk
from their own eggs, they eat the other eggs and hatchlings until one baby shark
from each oviduct remains. When they emerge, the young sharks
are well-nourished, experienced predators who stand a better chance of surviving. Even when they aren’t consumed
for nutrition, young animals are especially
vulnerable to cannibalism. Hamsters, rats, and other rodent mothers will eat some of their young
if they’re sick, dead, or simply too numerous to feed. In other mammals,
including bears and lions, males will kill offspring
sired by another. That’s because childless females become
receptive to mating more quickly than if they were caring for a cub. Rather than waste nutritious meat,
the males then eat the dead cubs. Meanwhile, cannibalism is less common
in birds than in other groups, but certain species will eat diseased
or dead hatchlings as a way of disposing of the
bodies before they can attract maggots. When adults eat each other, males are
cannibalized more often than females, usually during mating
and generally because they’re smaller. Male Australian redback spiders
mate with much larger females. Rather than scrambling away after mating,
the tiny male does a somersault, bringing his abdomen into contact
with his mate’s mouthparts. The female showers him with enzyme-rich
gut juice and consumes his abdomen. Males not killed in the initial mating
crawl back into the fray, often half-eaten, to mate again, after which they’re
dispatched to the spider pantry. So not only does the male provide
the female with his sperm, but he also provides her with
a nutritious meal to better ensure that she’ll
survive to pass on his genes. All in all, it’s clear
that cannibalism is as much a part of life
in the animal kingdom as other, better-recognized behaviors. As we sink our teeth into the evidence
of cannibalism in nature, we might ask ourselves, what else have we missed by applying
human standards to the natural world?

Cannibalism in the animal kingdom – Bill Schutt
Tagged on:                                                     

100 thoughts on “Cannibalism in the animal kingdom – Bill Schutt

  • March 19, 2018 at 3:09 pm
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    Sink your teeth into this fascinating subject by reading, "Cannibalism: A Perfectly Natural History" by the author of this lesson, Bill Schutt. Learn more on our TED-Ed Book Recs page: http://bit.ly/2HLWjrU

    Reply
  • July 26, 2019 at 10:29 am
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    her: i have a weird fetish
    austrailian redback spider: you sure bout that tho

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  • July 26, 2019 at 3:07 pm
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    This is the real "sacrifice yourself for your love ones"

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  • July 26, 2019 at 3:22 pm
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    Babies and the young are nutrient-rich meals! 😱

    Hey I'm just repeating what the video says

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  • July 26, 2019 at 7:19 pm
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    Being a future zoologist, this doesn't surprise me.

    But the male spider being such a devoted father did XD

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  • July 26, 2019 at 9:04 pm
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    So what you're telling me is male redback spiders are into vore

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  • July 26, 2019 at 11:32 pm
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    2:32 wow brutal

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  • July 27, 2019 at 5:29 am
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    No wonder my fish kept eating the other ones and kept getting bigger

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  • July 27, 2019 at 8:01 pm
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    finding nemo…… 😶

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  • July 27, 2019 at 11:36 pm
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    Hey isn't this agar.io

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  • July 28, 2019 at 4:34 am
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    Cobras' eat snakes and egg eating snakes eat eggs

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  • July 28, 2019 at 10:21 am
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    YOU FORGOT ABOUT DINASOURS

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  • July 28, 2019 at 2:02 pm
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    2:42 what is that sound? Should be a cave sound

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  • July 29, 2019 at 8:11 pm
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    I like Bill Schutt’s voice

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  • July 30, 2019 at 1:20 am
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    i swear if i see a comment of a female saying this is how guys should treat them

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  • July 31, 2019 at 7:31 am
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    I guess that's why Simba and Mufasa are the only lions in their pride huh

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  • August 1, 2019 at 10:02 pm
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    "Cull the weak, and bolster the strong" A great formula for Humans!

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  • August 2, 2019 at 4:26 am
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    3:43 what kind of vore-

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  • August 2, 2019 at 6:14 pm
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    Did the sharks really ate all of Nemo’s siblings… 😂

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  • August 3, 2019 at 1:05 pm
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    Crab eat his children

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  • August 3, 2019 at 3:03 pm
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    I show this video in court after eating my husband and kids and getting arrested

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  • August 3, 2019 at 6:18 pm
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    😳😳🥺🥺

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  • August 4, 2019 at 1:56 am
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    2:28 Sand tiger sharks?
    Check out Science Insider's video: The Most Extreme Babies in the Animal Kingdom
    But this video gives "survival of the fittest" it's meaning

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  • August 4, 2019 at 3:08 pm
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    I clicked this because I just read a post about how sometimes chickens just flip out and decide to just eat parts of each other or corpses of other chickens. Also about a Turkey that decided to just eat some of itself after it developed a wound.

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  • August 4, 2019 at 4:56 pm
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    Chicken is also a cannibal right?

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  • August 4, 2019 at 8:36 pm
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    cannibalism is just illegal abortion

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  • August 5, 2019 at 2:52 am
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    Maybe this is why my cat eats her offspring 🤔

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  • August 5, 2019 at 3:26 am
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    Wow I wish I had a man that was as dedicated as those male redback spiders😂 even after being eaten they go back for more if they can

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  • August 5, 2019 at 7:42 am
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    Some fish eat their egg while they begin parenting.after some batches they stop

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  • August 5, 2019 at 4:24 pm
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    This video made me hungry. maybe I should check out that restaurant down the street, I hear they have really good human meat

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  • August 5, 2019 at 10:57 pm
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    Enlightening

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  • August 6, 2019 at 1:51 pm
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    whenever i finish watching their videos…another interesting video pop outs…😫😫

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  • August 6, 2019 at 2:58 pm
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    this is where watching too many hannibal clips got me i guess….

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  • August 6, 2019 at 4:36 pm
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    The spider story just made me feel so awkward. Why would he let himself get voluntarily eaten? I mean, he offers his abdomen voluntarily to her! Why not just run away? And yes I know that it's part of their nature but I thought that the will to live and escape from death is fully natural!

    Reply
  • August 6, 2019 at 7:33 pm
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    If you reply i will look forward to giving you this cookie
    🍪

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  • August 7, 2019 at 1:44 am
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    Imma show this to the kids who listen to baby shark

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  • August 7, 2019 at 4:43 am
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    Wow animals are insane

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  • August 7, 2019 at 5:54 am
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    Your intro song gives me a headache

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  • August 7, 2019 at 5:55 am
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    See ? Fish eat their babies I think I have the right to eat them cause they kill themselves bruh

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  • August 7, 2019 at 1:41 pm
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    0:45

    So…. The spadefoot toad basically lives it's tadpole life being an Agar.io circle esting others?

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  • August 8, 2019 at 3:02 am
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    Aborted fetus should be eaten by its mother.

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  • August 8, 2019 at 3:26 pm
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    with some twins, doesnt one sometimes eat the other in the womb?

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  • August 8, 2019 at 3:50 pm
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    Dang, that's brutal, but oddly cool too

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  • August 10, 2019 at 6:56 am
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    These tadpoles playing agar io battle royale

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  • August 10, 2019 at 9:37 am
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    This is nature’s version of battle royal

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  • August 10, 2019 at 1:17 pm
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    This narrator reminds me of Mr. Hamilton from Vice. Hamiltons Pharmacopoeia is his show on the main Vice channel I believe.
    ~~~~
    @3:41 Spiders never fail to amaze.

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  • August 11, 2019 at 12:32 am
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    3:46 Me: Bruh

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  • August 11, 2019 at 7:21 am
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    Simba left the chat

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  • August 11, 2019 at 4:26 pm
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    0:45 whats the music you used?

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  • August 12, 2019 at 9:43 am
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    When i was a kid i pet 2 hamsters.. One morning, i found out one of my hamster dead and being eaten by the other hamster and i cried.

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  • August 12, 2019 at 11:49 pm
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    I had to read the comments after this one 😂

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  • August 13, 2019 at 12:32 am
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    2:37 du du dudu dudu du du

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  • August 13, 2019 at 3:13 pm
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    Did you know that the Christmas Island Red Crab eat its own crabs because they have hundreds of babies at a time.

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  • August 14, 2019 at 1:58 pm
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    So for those tadpoles it's like slither.io

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  • August 14, 2019 at 3:38 pm
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    Lmao his name tho

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  • August 15, 2019 at 3:32 am
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    This is literraly all the io games

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  • August 15, 2019 at 9:15 am
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    Coconut crabs💩👹

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  • August 15, 2019 at 9:30 am
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    I was so shooketh at the baby sharks' part what theeeeee heckkkkkkkk 😂

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  • August 15, 2019 at 3:17 pm
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    Them spiders know how it's done. Hear I thought cannibalism was rare and specific to only humans.

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  • August 15, 2019 at 11:07 pm
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    We should just eat other humans to solve world hunger and over population, what a great idea! 💡

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  • August 15, 2019 at 11:13 pm
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    If I was apart of any of these groups I would die instantly lol.

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  • August 16, 2019 at 3:05 am
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    Its like agar.io

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  • August 16, 2019 at 4:35 am
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    Wait a second we are mammals so if we eat mammals THEN WE ARE CANNIBAL
    It’s a joke btw

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  • August 17, 2019 at 12:22 am
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    In animals, it sucks to be a male. In people, it sucks to be a female.

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  • August 18, 2019 at 4:30 am
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    Spadefoot toads be playing agar.io

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  • August 18, 2019 at 5:54 am
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    Those tadpoles are really heckin' cute…

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  • August 18, 2019 at 5:38 pm
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    Big brother: dawg not finna cap, you looking real tasty right about now

    Little brother: say sike right now

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  • August 19, 2019 at 8:33 pm
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    All I gotta say is that’s the best lookin shark I’ve ever seen.👌

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  • August 20, 2019 at 2:46 am
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    Jeez, imagine dieing due to a hungry bro before you even got a memory

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  • August 21, 2019 at 5:18 am
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    That's SAD

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  • August 22, 2019 at 8:04 am
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    timetoeatsomehumans.

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  • August 22, 2019 at 11:42 pm
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    I learned my guppies were cannibals the hard way XD

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  • August 24, 2019 at 12:06 pm
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    i ate my brother because he was weak and in turned mate me stronger

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  • August 24, 2019 at 6:32 pm
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    the music is reversd

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  • August 24, 2019 at 10:21 pm
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    Did he just say toadlets

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  • August 24, 2019 at 10:25 pm
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    Turn off nature.

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  • August 25, 2019 at 6:08 pm
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    My hamster was a cannibal she ate my other hamster 😭😭😭

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  • August 25, 2019 at 8:44 pm
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    so how about apes and human? cannibalism?

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  • August 25, 2019 at 10:34 pm
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    Yo thats wild

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  • August 26, 2019 at 2:54 am
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    And then they will do a video about cannibals in the human kingdom

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  • August 26, 2019 at 3:03 am
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    Those toads be playing Agar.io irl

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  • August 26, 2019 at 3:37 am
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    But what if I eat myself?

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  • August 26, 2019 at 3:39 am
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    I feel like in the future the human race will have to do it as well…

    Not my problem though.

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  • August 26, 2019 at 9:03 am
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    My first experience of cannibalism is when I was 9 -10 years. I caught some dragons flies. Then I put them in the box. I atleast caught 10 -12 of them but when I opened the box only 1 survided that also half eaten. Now that is a good sport to bet in.

    Reply
  • August 26, 2019 at 1:38 pm
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    So sharks really are born killers!

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  • August 26, 2019 at 1:58 pm
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    That Australian Redback spider is a real gentleman

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  • August 26, 2019 at 9:32 pm
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    What

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  • August 26, 2019 at 10:16 pm
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    Don't start eating people plz

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  • August 27, 2019 at 11:41 am
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    It's funny to think that sand tiger sharks have a battle royale just to be born

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  • August 27, 2019 at 12:22 pm
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    Never forget that cannibalism also occurs with chickens too!

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  • August 27, 2019 at 3:36 pm
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    All while theres vegans walking around LOL

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  • August 27, 2019 at 6:37 pm
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    If its natural why don't we do it HHMMMMMMMMMMMMMMMM

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  • August 27, 2019 at 8:31 pm
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    Damn this is like Agar.io

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  • August 28, 2019 at 12:26 am
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    Them Aussie Redback spiders some freaks.

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  • August 28, 2019 at 3:11 am
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    I think to solve the over population of earth we should eat each other.

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  • August 28, 2019 at 9:33 am
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    why am I watching this

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  • August 28, 2019 at 9:19 pm
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    Humans do

    Reply
  • August 29, 2019 at 7:17 am
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    kinky

    Reply
  • August 29, 2019 at 8:59 am
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    How about komdo dragon is it cannibalism too right

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  • August 31, 2019 at 10:05 am
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    Just comment for me remeber how many subs 9835663

    Reply

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