Shark Eyesight | SHARK ACADEMY


How good is a shark’s vision? Do they see
as well as humans? I’m Jonathan Bird and this is Shark Academy! Since sharks have so many keen senses, like
smell and their electrosensory system, for a long time it was assumed that sharks were
making up for having bad vision. Well, turns out that’s just not true. The shark eye is remarkably similar to the
human eye. It has the same basic structure, with a cornea, lens, pupil and an iris. It
also has rods and cones in the retina, which means the shark can see in color. But we have
no idea what kind of color it can see in a blue environment. It can also open and close
the pupil, in response to available light, just like humans. And most fish can’t do this. The shark has a reflective layer behind the
retina called the tapetum lucidum. Its purpose is to reflect light back through the retina
a second time. It’s very similar to the eye of a cat. If you look into a shark’s eye at
night with a light, it will actually reflect back at you, just like a cat’s eye. This increases
the low-light sensitivity of a shark’s eye. They can see amazingly well in light that,
to us, would just look…dark. Some estimates say that the shark’s eye is ten times more
sensitive in low light than human eyes. And get this! Sharks also have eyelids! They’re
the only fish with eyelids. They’re called nictitating membranes, and they close them
when they are attacking prey at close range to protect their eyes. Sometimes when the
sharks come really close to our video cameras to investigate what they are, we’ll see the
nictitating membranes close. This is one of the reasons that people think that sometimes
sharks bite people by accident—because when they get really close to the prey, they actually
close their eyes, and they can’t see what they’re doing! Well, I hope that all makes sense and now
you can see why sharks are out of sight! I’m Jonathan Bird. Until next time, this is Shark
Academy! And, don’t forget to check out our other shark-related
videos on our channel!

39 comments

  1. This is a nice informative video. It sums up all the important facts realy well. One thing I missed however is the explanations how the different types of shark eyes evolved (eg. bulls and lemons on one and blue and mako sharks on the other, one sort living in shallow waters the other roaming the deep sea)
    Anyways keep those vids coming they are really entertaining, even for those who already know about the facts but watch them for the awesome footage.

  2. Did not know sharks have eyelids, and can see in color. If we figure out how, maybe someday we can technologically duplicate that for our own underwater vision.

  3. Jonathan I'm glad there is such a diver, before discovering your channel I used to spend hours watching low quality, boring vids about sealife and now I get this high grade stuff and such a charismatic professional. Thank you!

  4. i think sharks' eyes are kinda terrifying o_o
    for example, in one of the aquarium episodes, (can't remember which) there was a sand tiger shark (i think?) with EXTREMELY terrifying eyes.

  5. thanks for all of these info about sharks I love following the videos it is informative and I learn a lot about sharks. Now I know more about them and will love them when I see them swimming in the island.

  6. keep making this kinds of videos, I really like to learn about sharks. I also see all your Blue World videos.

  7. Cool sharks but to learn about them a lot in my classroom because we are learning a about and my class watches shark academy because we are learning sharks and there are two sharks that we have to learn but I forgot it's name.I watch this at home too and I'm already at home and watching this its my favorite learning channel and it's funny a little and sometimes it gets super duper funny and my classmates laugh and laugh a lot and then they stop right now.my classmates like watching shark academy and they really really really like it a lot and my brother did not heard of it because I did not tell him about it yet I still forget that's why.my cousin do not like being smart and his sister is already smart already and I'm almost smart too like her.i like learning and my cousin like too and my other cousin do not like to get smart like us.

  8. I was petting a lemon shark right by the nose are, and when I reviewed the footage I saw nictitaning membrane. The first day on my dive I was surrounded by 6-7 Bull sharks and few Lemons. That was amazing! I have a YT vid

  9. I asked all my teachers What Nictitating Membranes were (because I wanted to know what they thought) and only one of them knew (my science teacher, who I had faith in)! My best friend actually said that she thought it was when you smoke too much and the nicotine gets to your brain. We laughed so hard I thought that we might die. It was so funny. She was really embarrassed when I said that it was a shark’s eyelid

  10. We had to cut open sheep (or cow, depends who you chose) eyes in my Bio class and the tapetum looks so cool, I want one. They're all shiny and blue and purple, it's incredible. I'm super jealous of animals that have them.

    Also, sheep eyes are super hard to cut through and I was not expecting to have to use literally all my strength to carefully cut it in half.

Leave a Reply

Your email address will not be published. Required fields are marked *