Claire Corlett

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Coming up next on Jonathan Bird’s Blue World,
Jonathan explores the fascinating biology of slates and rays! Hi I’m Jonathan Bird and welcome to my world! You know me…I love sharks! It doesn’t
matter if it’s a big shark like the Great White or whale shark, or if it’s a small
one like the white tip reef shark. Sharks are cool! Skates and rays are the evolutionary cousins
of sharks—they are contained within the class Chondrichthyes along with the sharks,
but they are in their own sub-division known as the Batoids. The Batoids share many characteristics with
sharks, such as the cartilaginous skeleton, the lack of a swim bladder and multiple gill
slits. In fact, they are so similar that you almost could think of them as flat sharks. But there are some flat sharks. The Wobbegong
shark, for example, actually looks more like a ray than a shark, because it’s flattened
and tends to lie on the bottom. So how do you tell a ray from a flat shark? First of all, skates and rays are always flat.
Biologists call them dorso-ventrally flattened. But unlike a dorso-ventrally flattened shark,
a skate or ray has wing-like pectoral fins that are just an extension of its body, making
it look a bit like a flying carpet. Or maybe if you squint a little, a bat, hence the name
“Batoids.” Also, skates and rays have their gills on
the underside of their bodies, while a shark—even a flattened shark–has them on the side. One of the most well-known rays is the stingray.
This is a Southern Stingray, common in the Caribbean. It gets its name from its stinger—a
sharp venomous spine at the base of the tail. This powerful weapon is used to defend the
animal from its most feared predator—sharks! Wait a minute! Sharks eating their own evolutionary
cousins? That is so uncivilized! The Southern Stingray feeds on animals that
live in the sand, like mollusks and worms. The stingray’s mouth is on its underside,
just like its gills. It blows water into the sand to excavate around
prey, then slurps it up with powerful suction. Because it feeds in the sand, the Southern
Stingray tends to swim close to the bottom, though it certainly doesn’t have to. But
this poses a problem—with breathing! A shark breathes by taking water in through
its mouth and then sending it back out through the gills to extract oxygen from the water. However, since the stingray has its mouth
on its underside and swims so close to the bottom, you would think that the stingray
would get a lot of sand into its gills. And you would be right, except for one thing. On top of the stingray’s head are a pair
of openings called spiracles. They are kind of like big nostrils. Instead of breathing
in through its mouth, the stingray breathes in through the spiracles on top of its head
and away from the sand. Sharks have spiracles too, but they are really
small on most sharks, and they can’t breathe through them. The only sharks that breathe through their
spiracles are—you guessed it! Flattened bottom dwellers like the Wobbegong! Notice how this ray swims, by flapping its
wings and gliding along just over the sand. By comparison, meet the Little Skate, common
in the waters of New England. It looks just like a miniature stingray, but it’s a skate
because it has no stinger. Although it can swim by flapping its wings,
it often scoots along the bottom by repeatedly pushing off the bottom with its pelvic fins.
Kind of like riding a skateboard. This type of locomotion has been termed “punting.”
Most Batoids have pelvic fins like this, but only a few use them to move in this way. And if you think that’s weird, check out
this strange looking ray! The Torpedo Ray doesn’t look much different
from any other ray when it’s lying on the bottom. But when it gets up to swim…it has
a vertical tail fin like a shark! Instead of flapping its wing-like pectoral fins, it
swishes its tail back and forth to swim! And that’s not even the weirdest thing about
this unique ray. The Torpedo Ray is also known as the Electric Ray because it can produce
50 volts of electricity to shock its prey! Most rays can’t electrocute their dinner
into submission. The Spotted Eagle Ray spends a lot of time
soaring through the water like the Eagle for which it’s named. But look closely. It has
a shovel-shaped face for digging around in the sea floor. It’s a bottom-feeder like
the stingray. And look here! Not just one but three stingers! Another ray that likes to swim up off the
bottom: the manta ray. If ever there was an animal that looked like a flying carpet, this
is it. Unlike most other rays, this animal eats plankton. It swims through the water
with its mouth wide open, allowing the tiny plankton to go into its mouth and get stuck
on comb-like filters on its gills. Then it swallows them down. Mantas don’t have spines for protection.
They rely partly on their large size to deter predators. But they can jump pretty far out of the water
to escape predators too! Sometimes that doesn’t help. This manta
has a bite cleanly taken out of it by a shark! Ouch, that’s gotta hurt. It probably happened
when this ray was much smaller. Manta rays are ovoviviparous, meaning that
they produce eggs that hatch internally. Baby manta rays emerge from their mother alive
and swimming. All rays use this reproductive strategy. However skates, like the Little Skate, are
oviparous—they lay eggs. This is the egg of a skate. The mother produced 5 to 15 of
them. They are laid on the sand and given no parental protection. Inside the egg, a baby skate develops, for
up to a year, dependent on water temperature. Finally, the day comes when the baby skate
slowly forces its way out of the egg case and swims away. Even a newborn knows to camouflage itself
quickly to avoid predators. Skates and rays are a diverse group. Not all Batoids look like the typical ray.
This animal is called a Sawshark or sawfish. It looks more like a shark, but it is a ray.
Don’t believe me? Where are its gill slits? A shark’s gills would be here, but they’re
underneath. And look, its breathing through large spiracles. The Sawfish uses its saw to hunt by swinging
it back and forth in the sand, impaling soft-bodied creatures on the teeth. So skates and rays are a diverse group of
animals with many adaptations to survive. And while they are not as well-known as their
cousins the sharks, they’re every bit as fascinating.

100 comments on “Skates and Rays! | JONATHAN BIRD’S BLUE WORLD

  1. Saw a skate in the surf near the beach on LBI today. Avery cool considering they almost never come near the coast! Gave me quite a scare!

  2. 6:34 the eagle Ray has three stingers, two more than the stingray. So why is the stingray called a stingray when other rays have more stingers than it. Call it the sand ray and the eagle ray, the Eagle Stingray.

  3. Really awesome video, this was so helpful..I'm pretty sure you highlighted the sharks nostril when you were referring to it's spiracle(s), since spiracles are posterior to the eyes.. And the spiracle isn't really like a nostril, just confusing because the rays nostrils are ventral by its mouth. Also, the sawfish uses spiracles, but so do many benthic sharks, so that's not why it's a ray

  4. I LOVE SHARKS TOO! I've been so afraid for so long until I saw all these videos of how they actually are. Can't wait to have a great contact experience with sharks!

  5. Mr Jonathan plz go and explore Lakshaweep island where you will find different kind of sting ray and many variety of fishes blue lagoons

  6. I recommend doing a video on the angleshark. they are very endangered so I would do it soon so it doesn't become extinct. they also are a type of flat shark or really look like one

  7. someone on Discord just introduced me to your channel and I've subscribed… sorry I was late being able to find this channel

  8. Great informative footage delivered with such humorous narration.. thanks for capturing the hatching off the sack looking egg, never seen before, and the saw fish!! Amazing beautiful creatures.

  9. Wow such an informative video👌… I just love your channel♥️♥️♥️… It is always like coming with you for a deep sea dive!!!

  10. What’s your favorite Batoyed mine the manta ray because they’re the biggest also they’re really friendly

  11. On a video I saw a hammerhead catch a stingray for food when it count it a tiger shark tried to still it

  12. "I didn't know that a saw shark wasn't really a shark. The more you know in Jonathan Bird's Big Blue World!"

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