Our Halloween haunts are usually based on the supernatural,ghouls, zombies,
vampires, sexy kittens. But the scariest
monsters of all are the ones found in
the natural world. Cannibals.
[male announcer] Consistent reports from witnesses
to the affect that people who acted as though they were
in a kind of trance were killing and eating their victims
prompted authorities to examine the bodies
of some of the victims. [female announcer]
Dinnertime is happy time for this family.
[male announcer] In all cases, the killers are eating the flesh
of the people they murdered. [♪♪♪]
Hi, I'm Jess Keating,
and you're watching Animalogic: Second Nature.
The natural world is filled with animals whose feeding strategies
rely on eating members of their own species.
These are nature's best cannibals.
Cannibalism is seen in a wide variety of species,
from those who look the part to those who don't.
While nature may hold no moral judgement on cannibalistic
species, that doesn't mean that cannibalism
doesn't have its negatives. [male announcer] Civil defence
authorities have told newsmen that murder victims show
evidence of having been partially devoured
by their murderers. [Jess]
First of all, disease. It is much easier to get
sick from a member of your own species than another species.
So eating your cousin increases your chances
of contracting a disease. [woman] "We'll be ready to eat
as soon as father comes home. My, I hope he's not
late, don't you?" [Jess] Secondly, the most
common victims of cannibalism are youth, and if you
eat your own offspring, your genes won't be passed on.
[woman] "How soon do we eat?" Right now, says Mother.
Smart cannibals will avoid eating their own children
and instead cook up their neighbour's kid
with some fava beans and a nice Chianti.
For example, paper wasps and tiger salamanders
have been seen to be less likely to eat relatives
whom they can identify via smell.
Similarly, spadefoot toads will avoid eating their siblings
by hanging out in areas with a high density of unrelated toads.
The paper wasp is an exception, however.
Most invertebrates rarely recognize kin and will devour
members of their own
species, relative or no. [male announcer] The wave of
murder which is sweeping the eastern third of the nation
is being committed by creatures who feast upon the
flesh of their victims. One big advantage of cannibalism
is it gives you an extra food source when times get tough.
Snowy egrets and many rodents, rabbits,
and shrews will cannibalize the weakest of their babies
in long winters and in times of scarcity.
Fish on the other hand don't really care about
the time of year.They'll eat their tasty, nutritious young
whenever they need a meal. They will even
eat their own eggs. When males are
guarding their eggs, they will pop one or two
back when they need a snack. And if they're really hungry,
they'll wolf the whole brood down.
There are many things that you can do to help yourselves
from becoming victims. Well, if you let me take you
to school, I'll give you this pretty little dolly. Okay.
All right, darling, come on. [Jess] Cichlids will put
their babies in their mouths for protection.
This may look cute, but often times they will swallow,
eating their entire family in one gulp.
Some shark species,
like the sand tiger shark, practice in utero cannibalism.
These shark's eggs hatch in their mom's oviducts.
Once hatched, the stronger pup will eat the other,
eventually giving them the strength of a full-grown shark
and a little baby. Though it's not always
parents feeding on the babies, sometimes it's the
other way around. These are cannibal babies.
Black lace spiders for example
might just be the best mothers on the planet.
They will care for their spiderlings a few days
after they hatch, but soon after, the babies will need
a lot of food in order to build up energy to moult.
So the mother sacrifices herself,
allowing her babies to devour her alive.
In some snail species, they practice sibling cannibalism.
Rock snails will lay hundreds of eggs,
but only about 15 ever hatch. The ones that do hatch will
make the unhatched eggs their first meal.
These snails are born unable to digest their adult vegan diet,
so until they acquire the necessary gut bacteria,
they cannibalize their siblings. Conversely, spade foot
toads begin their journey as vegetarian tadpoles,
but as they grow and develop,
they become cannibalistic, eating the younger tadpoles.
These tadpoles eat their own kind because their ponds
can dry up quickly and suddenly, so they either grow fast or die.
Anything that can help them grow as quickly as possible
and climb out of the volatile ponds as toads is a huge help.
This is the biggest advantage to eating
members of your own family.
You can get a lot of energy in a short amount of time,allowing you to grow and
reproduce and pass your genes on to the next generation.
I guess, just like in humans, the first suspects are
always your family. Polar bears are of the most
famous infanticidal cannibals. Cubs are part of a
balanced breakfast for an adult male polar bear.
While there has been speculation that it's climate change
that has forced them in to cannibalization,
polar bears have always been cold hard cannibals.
Probably the most misunderstood
form of cannibalism is sexual cannibalism.
There is no more deadly or veracious creature
than the praying mantis. [Jess] You've probably
heard that black widows and praying mantises both
devour their mates after sex. While it can happen, it's
not nearly as common as you may think, and the
notion is based on bad science. When they conducted the study
that found that female mantises eat males after mating, they
had starved the females for several days prior.
In natural conditions, both mantises and black widows
are quite comfortable with males not being dead after mating.
That said, if either female is hungry,
she will bite his head off. [male announcer] Usually,
she does not attack the male as he tries to secure her
with his own ineffective web. Only when prompted by strong
hunger does the black widow kill and eat the male after mating.
[Jess] The real sexual cannibals are the Australian red backs.
When mating, the male spider will go on top
and put his abdomen near the female's mouth.
During the act, the female will bite into his body
for a little snack. If the male survives, he may
return for a second round. But no male has ever
gone more than two rounds and lived to spin the tale.
This is another good example of spiders being great parents.
The male is sacrificing himself for the chance of producing
better eggs. Several mammals will
cannibalize a mother's young as a mating strategy.
Seen in both chimpanzees and lions,
dominant males will kill and often eat all the female's cubs
as it causes the mother to come into estrus soon after,
allowing her to bare his cubs much sooner.
Nothing turns a woman on like eating her
babies in front of her. [male announcer] And
when it was morning, the east wind
brought the locusts. They did eat every
herb of the land. [Jess] Mormon crickets practice
cannibalism due to overcrowding. They move in giant swarms
devouring all the food sources in their path.
Often there isn't enough food to support the entire swarm
and so members are left with no choice but to eat each other.
Factory-farmed chickens will exhibit similar behaviours
if they're packed too closely together,
turning to cannibalism out of stress.
They will peck each other to death
and cannibalize the corpse. Stress will also force a bout
of cannibalism on the cutest cannibalistic species, the hamster.
If a hamster gets too stressed out,
often caused by small cages with nowhere to hide,
they will eat their pups.
Mothers will also cannibalize their young if they are sick,
dead, or if there are just too many of them.
But it's not just the babies that get eaten.
Sometimes adults of the same sex,
if placed in the same cage, will fight to the death
and the winner will feast on the carcass of the looser.
Thankfully, they don't usually cut off the face of their victim
and wear it around... usually.
I caused a good part of the trouble by not
having dinner on time. That does it.
So what should we talk about next?
Please let us know in the comments,
and as always, don't forget to subscribe for new episodes
of "Animalogic: Second Nature" every other week.
Thanks for watching. Oh, I almost died .