Do you know about sharks?
Why can't you catch the shark?
Why do you always catch up to throw up?
Because sharks have very sensitive senses,
When you haven't seen it, it has already started to avoid you,
Do you know about sharks?
Let's start with its perception system.
01 Shark Sensation - Long Distance
hearing
Sharks have a long-distance and highly developed auditory system,
It can also provide important information about potential prey.
This usually occurs before the animal is within visual range,
They are especially good for listening to low frequency sounds,
This sound is made by wounded or struggling fish,
And are able to detect them often from a distance of more than a kilometer!
the sense of smell
Sharks have a very sensitive sense of smell.
And can well regulate amino acids in proteins, such as blood,
research shows,
A shark can detect as little as one millionth of blood in water!
This is a shark's cue to potential prey in the distance.
02 Shark Feeling - Middle Distance
vision
Sharks actually have pretty good eyesight,
They lack color vision and only see black and white photos,
but still have the visual perception equipment to produce a focused image,
The water environment plays a large role,
Low light or dim water can have a big impact on their vision.
lateral line organs
Sharks have evolved a sense of being very alien to humans,
The lateral line system is a series of canals running through the shark's body,
Its opening has skin, which allows water to enter,
and is very sensitive to water movement,
Sharks are therefore able to sense vibrations caused by injured or struggling fish,
Again, help them catch potential prey.
03 Shark Awareness - Up Close
Ampullae of Lorenzini - Inductors
Another feeling that we are not familiar with is inductance.
Sharks are able to detect the weak electric fields emitted by all living things,
This highly attuned feeling,
Thanks to the countless tiny holes in the shark's skin,
mostly concentrated around the snout, known as the ampulla of Lorenzini,
These filled pores help amplify these weak electrical signals,
detects prey even when the shark is completely hidden in the sand,
It is effective at close range, usually within 1 meter.
04 Shark Vision
Sharks lack color vision
is this real? Do sharks have poor eyesight?
Yes, sharks lack the cells necessary to process color vision,
They can only see black and white,
This seems to be the case for all sharks,
Because there aren't those photoreceptors necessary to see color.
(Most animals are basically like this~)
Shark vision has always seemed a little mysterious,
We often see images of sharks interacting with humans,
This has led many to believe that sharks have poor eyesight,
We also often hear that sharks only have an amazing sense of smell,
So people often think that sharks' other senses are useless,
In fact, they may be the world experts on vertebrate vision.
visual acuity
Sharks are thought to be able to see very focused images,
Shark vision is monochromatic,
That doesn't mean they lack visual acuity,
In the human eye, we have muscles that control the shape of our lens,
Focus the light signal on the retina.
In contrast, the see-through mirrors in shark eyes do not change shape,
They use their muscles to move the lens forward or backward to focus the light.
In both cases the effect is the same,
The retina receives the focused image,
So sharks have strong visual acuity,
Sharks are very dependent on many of their behaviors,
Obviously, the water environment will have an effect on what they see,
As well as the ability to see at a distance has a major impact.
Although their eyesight is good,
But they also combine with the nerves on the sides of the body and the sense of smell,
In order to accurately judge the surrounding environment and other factors,
It's important for them,
So they get closer and closer to their prey.
light sensitivity
In low light conditions,
The observed ability varies widely among shark species,
Basically, there are 2 types of photoreceptor cells in the retina,
In bright light conditions the "cones" are active,
"Rod cells" are active in low light conditions.
Each species will have a different proportion of these cells,
The large eyes of deep-water sharks have higher low-light perception "rod cells",
Shallow-water sharks have the exact opposite cell ratios.
also,
Sharks have a structure called Tapetum lucidum,
This is the reflective part of the eye,
Located behind the retina, causing "glowing eyes",
(For example, usually you see cats or deer in headlights....)
This actually reflects the light back to the retina again,
Thereby making it available to the retina a second time and increasing low light vision.
actually
Sharks have monochromatic vision, sharks have very good eyesight,
Sharks have vision adapted to their environment.
How to Get Closer to Sharks
Do we need to worry about the color of our dive gear?
In short, yes!
This is why we don't like very bright colors on diving gear,
Because it might interest them!
That's why we ask divers and shark diving to wear gloves,
A pale fleshy hand stretches out of a black wetsuit sleeve,
It might cause trouble!
Are you ready to swim with sharks?
We need to consider a factor,
general physical fitness in relation to diving,
Normally, we have to endure strong currents,
This is why it is important to understand the body's own capabilities and limitations,
poor cardiovascular regulation, along with feelings of anxiety and adrenaline,
Allows divers to perform rapid and erratic movements underwater,
This movement tends to stimulate the sharks,
Obviously not the behavior you want to elicit,
the ability to remain calm and control your breathing,
Critical to preventing this behavior from happening!
if you want to take pictures of sharks
certainly! Under the condition that we turn on the flash,
Be careful not to overexpose the shark,
And their bellies and faces!
Many sharks are attracted to electrodes from certain flashing lights,
Sometimes flashes and even camera cases become their expensive chew toys!!
"Close Encounters" with Sharks
Obviously, before the shark bites,
Often encounters potential prey,
to detect what you're dealing with,
Without hands, the shark hits the water column with its nose,
It's common to even use your mouth to detect things in the water column,
This is the cause of the often described bumps and bites,
Also why divers know they can't let a shark hit you,
Because they usually end up with a test bite.
(The picture comes from the Internet)
don't make yourself look like a fish
In the eyes of sharks, the flash is likely to be a symbol of "fish here",
This is especially important in turbid waters,
Because it is difficult for sharks to judge whether the flashing light is a human or a prey,
A surfer might be mistaken for a seal by a shark,
When humans wear wet bathing suits and rest on surfboards,
From the shark's point of view, the outline is very similar to that of a seal.
(The picture comes from the Internet)
Hate your shark--
Even though sharks have taste buds,
However, sharks have become the first fear of most people,
In fact, instead of discussing whether sharks can eat people,
It's better to discuss whether the next person is worth eating by sharks.
Sharks have very high requirements for protein and other nutrients,
The nutrients in humans are simply not enough to supplement the needs of sharks,
So in other words, there is no need for sharks to eat people!
(The picture comes from the Internet)
The shark's attack line is upwards from the top of its head,
The targets of shark attacks are also creatures like seals in shallow water.
It also confirms the above paragraph,
"Don't make yourself look like a fish" in the water! !
Familiar with the perception of sharks,
mastered the art of approaching sharks,
You know how to catch a shark!
At least the next time you chase whale sharks, hammerheads, whitetips, blacktips, bullheads... it will save you 10 bar.
PS: More exciting content is waiting for you to watch!
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