(phone ringing) - Hi, it's Doug. I want
to show you something. This is a purple-striped
jellyfish. Pretty cool, right? Jellyfish are some of the
ocean's most beautiful and graceful creatures, but even though they look soft and gentle, a lot of jellyfish actually
have a powerful sting. Someone named Crystal has
a question about jellyfish. Let's give Crystal a call now. (phone ringing) - Hi, Doug.
- Hi, Crystal. - I have a question. How do jellyfish sting? - Ooh, I wonder that myself, and I know just the person
to answer this question. Her name is Esther Ikoro. She's an explorer who loves
learning about wild creatures. And she's really good at noticing interesting things about them, too. Esther's going to be joining me this year in answering your questions,
so you'll see her around a lot. Let's give Esther a call now. (phone ringing) - Hey Doug, I heard you had
a question about jellyfish. - I do. Crystal wants to
know, how do jellyfish sting? - That's a really interesting question. Okay, so jellyfish look
squishy and harmless, but all the things that
make them so soft and gentle are actually the reason
they need to sting. If you look closely at a jellyfish, you can see that they don't
have a lot of the things that other animals have to protect
themselves or hunt for food. They don't have hard
shells like a sea turtle or sharp teeth like a great white shark. Jellyfish don't even
have bones or a brain. Their soft, simple bodies
make it hard for them to catch food and keep
predators from eating them. That's why jellyfish sting. It's how they capture prey
and protect themselves. You can probably think of
other animals that sting for the same reasons, like
bees or wasps or scorpions, but unlike a wasp, which
has a pointy stinger that sticks out from the end of its body, or a scorpion, which
has a big stinging tail, the way a jellyfish stings is hard to see. So before we go any further, I want to know how do you
think jellyfish sting? Now would be a good time
to stop and discuss. Are you ready? Okay. To help us find the
answer to this question, let's take a closer look at the
parts of a jellyfishes body. Most jellyfish are made
up of two main parts. The first part is the bell, which is the part of the jellyfish that's kind of shaped like an umbrella. The muscles inside the bell
power the jellyfishes movement, helping it pulse through the water. The second part is the tentacles. Jellyfish tentacles trail
behind their bell in the water. These tentacles can look really different on different kinds of jellyfish. Some jellyfish have short
and stubby tentacles, like this blubber jelly. Some are colorful, like
this Pacific sea nettle. This jellyfish, called
the lion's mane jelly, has tentacles that can
grow over 100 feet long. That's longer than a blue whale or three school buses put together. Now, jellyfish tentacles may look like they don't do very much, but that's actually the part
of the jellyfish that stings. If you take a close look
at a jellyfish tentacle with just your eyes, you
won't actually see anything that can sting, and for a long time, scientists didn't know how this worked. But once the microscope was invented, then people were able to
take an even closer look at jellyfish tentacles, and what they found was really
surprising. Check this out. What they found was that there
are lots of tiny little darts inside of a jellyfishes tentacle. Those darts contain venom, and when something brushes
against the jellyfish, the darts automatically
fire and inject venom into whatever's nearby. If a jellyfish brushes
up against something it likes to eat, the
venom stuns the creature so the jellyfish can eat
it before it gets away. Now, not all jellyfish sting, and most of the ones that do
sting are harmless to humans. But some jelly stings
can be painful or itchy and a few are actually dangerous. The most venomous jellyfish
in the entire world is called a sea wasp. The sea wasp is so deadly that it's sting can stop a human heart if the person doesn't get
medical help quickly enough. But are jellyfish the only sea creatures who sting from their tentacles? Turns out, lots of other
creatures sting this way. Take a look. This is coral. They look like plants, but
they're actually animals. In fact, corals and jellies are relatives. They're both in a group called cnidarians. Corals live underwater, attached
to rocks on the sea floor. They have a body on the
bottom and tentacles pointing upwards into the water. Just like jellyfish, corals tentacles also release venomous darts to catch food. So corals are kind of like
upside down jellyfish. Try this, extend your hand
with your palm and fingers pointing down like this. Imagine your hand is a jellyfish
with your palm as the bell and your fingers as the tentacles. Now wiggle your tentacles like they're waving in the water. Next, flip your hand
upside down like this. Now your hand is like a coral
with a body on the bottom and the tentacles pointing upwards. It's the same structure, just
facing different directions. And when jelly fish are babies, they look even more like corals. This is a baby jellyfish. At this age, baby jellies
attach to the sea floor and catch plankton with
their stinging tentacles pointing upwards, just like corals. But wait, there's more. Many other cnidarians, like sea anemones and hydras, sting too. So in summary, even
though jellyfish look like they're the most gentle
animals in the sea, they're actually part of
a whole group of beautiful sea creatures that use
their tentacles to sting. Cnidarians, which include
jellyfish, corals, and other creatures,
release tiny venomous darts from their tentacles to catch food. They're pretty to look at, but they also know how
to get what they need. That's all for this week's question. Thanks for asking, Crystal. - [Doug] Now we'll be
back with a new episode in a couple of weeks, but in the meantime, here are some older questions
from the question jar. You can vote on which one you think we should send out next week. You can choose from, do
bats really drink blood? Why do our skeletons have so many bones? Or, what is the biggest
spider in the world? So submit your vote
when the video is over, we want to hear from all of you watching. There are mysteries all around us. Stay curious, and see you next week.
