Anna: They snap, they trap, they stick, and
they suck. This is the bizarre world of carnivorous plants—leafy
creatures that eat everything from insects, to crustaceans, to mammals. I’m Anna, and this is Gross Science. The vast majority of plants only require a
few things to survive: sunlight, water, air, and mineral nutrients, which they typically
get from the soil or pond water they’re growing in. These nutrients are elements like nitrogen
and phosphorus, which are building blocks for things like DNA and proteins. But most carnivorous plants live in places
without a lot of nutrients, like peat bogs. So to really thrive, they draw extra nutrition
from the bodies of unsuspecting prey. Now, carnivory has actually evolved multiple
times in plants all over the world, giving rise to some wildly diverse and morbidly beautiful
methods for catching food. So, Vanessa from BrainCraft and I bought a
few carnivorous plants! Vanessa: They’re so beautiful. Anna: They really are. Vanessa: Yeah. Anna: And I’m going to show you some of
my favorites. You ready, Vanessa? Vanessa: I’m scared and kind of excited
all at once. Anna: Me too! Ok, so first, this is the bladderwort. These guys live in watery environments, but
they have these small, empty chambers growing from their stems. When a tiny creature—like a crustacean—passes
by, it brushes against these things called trigger hairs. The hairs make the door to the chamber pop
open, and as water rushes in to fill the empty space inside, the tiny crustacean gets sucked
in, too. This entire process happens in less than a
thousandth of a second—the video you’re watching here has been slowed way down. Then the bladderwort releases digestive enzymes
into the chamber to break down the insect’s body and lap up its nutrients. After its meal, the chamber squeezes out all
the water, closes the door, and is ready to catch more prey. Vanessa: Wow. Anna: But that’s only one variety of carnivorous
plant. Other types of carnivorous plants act totally
differently. For example, the leaves of sundews are covered
in delicate, wispy hairs, each with a teeny drop of liquid at the end. Thinking the liquid is actually delicious
nectar, insects fly in to grab a tasty drink. But those dewdrops are actually sticky and
trap the bug. The wispy tentacles curl around the insect,
holding it tightly and maximizing the number of hairs it touches, which speeds up digestion. Vanessa: What I find so cool is the way sundews
operate is like a botanical version of brains and muscles . So, while they don’t have
brain cells they do have chemical signals to move which kind of acts as a brain. Anna: That’s so amazing, it’s a really
good analogy. The other really cool thing is that there
are actually some carnivorous plants that actually capture prey without moving at all. So, pitcher plants have deep basins filled
with digestive enzymes. Insects venture in looking for food, but then
they can’t get back out. There are tons of different varieties of these
plants, but in this species, called Sarracenia flava, the inside of the pitcher is slippery,
so bugs fall in and then can’t crawl up the walls. They also have downward pointing hairs at
the bottom of the pitcher that make climbing out even more difficult for the insects. And some species of pitcher plant can catch
more than just bugs. Certain tropical pitcher plants are so large
that they’ve been known to trap small rodents, like mice and rats. Vanessa: That’s scary. That’s very scary. Anna: It absolutely is. But, next is a type of plant that might be
a little bit more familiar. Vanessa: It is more familiar. Anna: This is the Venus flytrap. These plants have book-like leaves, which
emit a sweet smell that attracts insects, like flies. When a fly lands on the leaf, it brushes against
trigger hairs. Touching the hair sends a little electric
charge through the leaf. And each charge stimulates pores to open,
which allow water to move from one part of the leaf to another. The changes in water pressure make the book
snap shut in under a second. However, the plant will only close if at least
two hairs are touched in under about 20 seconds—or if the same hair is triggered twice in the
same amount of time. Then, the struggling prey needs to touch more
hairs before the flow of digestive juices begins. This keeps the plant from wasting precious
resources on a false alarm—like a floating speck of dirt or a curious human setting off
the snare for fun. Vanessa: So, when you’re talking about these
electrical charges, you’re really referring to something called action potentials. And these are signals our own brains’ neurons
use to pass on information to each other. So, we don’t tend to think about it, but
it’s kind of amazing how similar we are to plants. Anna: Yeah, we don’t tend to think about
it and that is really amazing. And Vanessa actually has a whole video about
this over on her channel, and I’ll put a link to it somewhere on this screen. Definitely go check it out. It’s so cool. Vanessa: Thank you. Anna: Anyway, these were just a few examples
of the diversity of these deadly traps. But the variety out there is really quite
extraordinary—in fact, there are over 750 individual species of carnivorous plants worldwide. And by the way, many of them are easy to find
and to care for. So if you have some of these plants at home,
let me know. I’d love to see your gruesomely beautiful
garden grow. Vanessa: This one’s really sticky. Anna: Ewww!
That was uncomfortable to watch
And Hugh Mungus smiles