NARRATOR: It calls to mind events that occurred
more than a century ago, which means
the key to the present dilemma may lie in the past.
DAN HUBER: Understanding patterns in historical attacks
can also help us to understand patterns in current attacks.
NARRATOR: So experts are turning their attention back,
all the way back to the very first significant shark
attack spike in US history--
1916, the Jersey Shore, when terror reigned.
MICHAEL CAPUZZO: The 1916 shark attacks on the New Jersey Shore
are the greatest shark attack mystery of all time.
And really, the movie "Jaws" and the book
would not have been possible without it.
NARRATOR: Though people at the time
believed sharks to be harmless, five beachgoers
are bitten in just two weeks.
Four lose their lives, causing panic up
and down the Eastern seaboard.
For years, experts have studied these attacks
and struggled to explain what happened.
But there is one parallel between the very first
fatal attack in 1916 and one of the more
recent attacks that might prove to be more than a coincidence.
They both happened at similar times of day.
In 1916, the first fatal victim was bitten around 5:00 PM,
just like Ida Parker.
IDA PARKER: It was about 5:00 in the afternoon.
NARRATOR: And according to shark expert Dr. Dan Huber,
this may not be mere chance.
DAN HUBER: Recent research has shown that sharks can use
the angle of the sun in order to give
them a predatory advantage.
NARRATOR: If a shark is hunting when the sun is high overhead,
the water is brightly lit and potential prey can easily
see the shark's approach.
DAN HUBER: It's going to illuminate the shark.
Perhaps so much so that it's really
not worth their time to hunt during the middle of the day.
NARRATOR: But when the sun is lower in the sky,
like it is around 5:00 PM, everything changes.
To explain, Huber sets up a demonstration.
DAN HUBER: Here we have a small lure,
which represents the shark.
Next, we have a GoPro camera, which represents
the point of view of the prey.
And last, we have the light, which represents the sun.
NARRATOR: When the sun is close to the horizon,
sharks approach prey using a very clever method.
DAN HUBER: They'll position the sun behind themselves
so if the prey were to look where the shark is coming from,
it's going to be blinded by the sun.
As you can see from the footage, the scene
gets completely washed out, making it harder
to see the oncoming predator.
NARRATOR: This may be key to understanding the attacks.
Because due in part to this camouflage,
sharks often hunt at two particular times of day.
DAN HUBER: Sharks will be more actively
hunting during dawn and dusk.
NARRATOR: As a result, experts the world over advise
beachgoers to avoid the water both early
and late in the day when they may run into a hunting shark.
So were beachgoers in 1916 and today simply swimming
during these dangerous times?
Huber examines the data and finds
that, while most of the victims in both spikes
were bitten during the afternoon,
none were bitten at dawn or dusk.
DAN HUBER: So the idea that this would have caused the attacks
simply isn't supported.