When a shark bites a human,
they never get the same taste,
let's say, as they
would by biting a fish.
So generally, they will
release us and swim away.
These incidents were
totally different.
The shark came in, attacked
the victim, and came back
and attacked again
and again and again,
and stayed with the
victims until they
were removed from the water.
That's a very determined animal.
NARRATOR: So what could
cause sharks to display
such brazen determination?
For Collier, there can
be only one explanation.
In my opinion, these animals
were not investigating.
These were all
predatory attacks.
These sharks were attempting
to feed on the victim.
NARRATOR: Sharks trying
to feed on humans.
It's a terrifying and virtually
unprecedented revelation.
It's extremely unique
and very, very rare.
And we had to find out why.
NARRATOR: So what
could cause Egypt
sharks to suddenly
start attempting
to actually eat beachgoers?
For Dr. Dan Huber,
such unnatural behavior
suggests that something
equally unnatural
must be occurring in the
predator's environment.
In fact, it could point to some
kind of human intervention.
Animals can be trained to
exhibit certain behaviors
in response to a stimulus.
And the reason why this
works is because the stimulus
is associated with a reward.
NARRATOR: This concept
is known as conditioning.
One of the primary
ways that this happens
is if a shark gets
hand fed over and over
and over again, it's
learning to associate people
with a food reward.
Which means that it's
going to exhibit feeding
behaviors around people, even if
that food reward isn't present.
