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Go to Brilliant.org/SciShow  to learn how you can take your STEM skills to the next level  with their interactive courses! [♪ INTRO]. In the insect world, there are few creatures  as gentle and innocent as a butterfly.

And yet, some butterflies have  an unexpected side to them. According to research published last week  in the journal Ecology, some species of butterflies scratch open living caterpillars  and feed on the liquid that oozes out. And while cannibalizing their  own species might not seem like a winning survival tactic, weirdly enough,  that might be exactly what it is.

The discovery of this behavior actually wasn’t  part of a scientific observation at all. It happened by accident, thanks to  two friends on vacation in Indonesia. Both of them happened to be scientists who were big on butterflies and photography.

So, one day, they were out taking  pictures when they came across a large gathering of butterflies  in a forest near a beach. They took a lot of photos, as big nerds  will, but it wasn’t until they were going through their pictures later that  they realized what they’d really seen. The butterflies were engaged  in a violent feeding frenzy.

And they weren’t just eating their usual nectar. They seemed to be eating  something oozing off caterpillars. The friends were so fascinated that they came back the next two days to document the action. ‘Cause what else are you gonna  do when you’re on vacation?

They saw butterflies use the  sharp claws on their feet to scratch open caterpillars until they oozed. And then the butterflies began to feed. They fed on live and dead  caterpillars, sometimes in large groups or for hours at a time.

And while they ate, the butterflies  were so absorbed that they didn’t even notice being touched by people. The friends thought that this was strange. So after their vacation, they started  trying to understand what was going on.

They saw that the butterflies in  the photos all belonged to the family that includes monarchs,  known as the milkweed butterflies. As caterpillars they feed on milkweed plants, which contain chemicals known as alkaloids. These are toxic to vertebrates,  so by ingesting them, caterpillars turn themselves into  a dangerous snack for predators.

And alkaloids remain important after  caterpillars become butterflies. Not only do they help keep predators  at bay, they’re also used to make chemicals called pheromones that males spray on females to lure them  in during courtship rituals. So between protecting against  predators and helping attract mates, alkaloids are super useful.

In some cases, butterflies get alkaloids  by scratching and sucking at leaves. And, as the researchers themselves put  it, when you really get down to it, caterpillars are essentially  just bags of chewed-up leaves. So maybe it’s not unthinkable  that butterflies will attack caterpillars of their own  species for a hit of alkaloids.

But scientists are not sure  that that’s all there is to it. There’s still a lot they don’t know. Like, it’s not clear how widespread  or common this behavior is.

And scientists can’t say for sure  that the butterflies aren’t just accidentally wounding the caterpillars  as they scratch at leaves. Plus, even if they are going after caterpillars, these observations alone don’t prove that  it’s the alkaloids the butterflies are after. These will be questions for follow-up  studies, maybe follow-up vacations!

Right now, all we do know is that  milkweed butterflies are not necessarily the whimsical, innocent  creatures that they seem to be. Speaking of animals with creative  survival techniques, another study published last month shared some  surprising findings about wild cockatoos. The study, which was published  in the journal Current Biology, found that wild cockatoos  native to Indonesia know how to whittle sticks into tools and use them to  hack into a tropical fruit for its seeds.

Now, on one hand, that’s not so surprising.  Any old crow or dolphin can use a tool. But what makes cockatoos special  is that they use a set of tools. They have three distinct tools that they use for different functions in a specific order.

And outside of primates, they’re  the first animal found to do this. The cockatoos in the study,  known as Goffin’s cockatoos, have been seen using tools in captivity. But the authors of this study wanted to  see if they would do the same in the wild.

Unfortunately, they didn’t have much luck  actually observing wild birds’ behavior, so after hundreds of hours staring up at trees, the researchers brought small flocks  into captivity for short studies. At first, the birds didn’t seem to  use tools like their counterparts who were raised in captivity. But then researchers offered them  some local fruit known as wawai.

The wawai is a tricky nut to crack:. It has a fleshy exterior covering  a hard pit full of seeds. Still, two of the 15 cockatoos in the study quickly showed that they knew what to do.

After biting away the flesh, one  cockatoo snapped a branch from a tree and used his beak to carve it  into a sturdy, blunt tool. Then he picked up the pit of the fruit in  his left claw and used his beak to wedge the tool into a fissure at the end of the pit. Once it was in, he pried open the pit.

From there, he and the second bird both  used their beaks to pull a splinter from a branch, which they used to  puncture the thin skin around the seeds. After that, they used the same  method to make a slightly larger, toothpick-like tool to pry the seeds out. And while this particular study  happened in a lab, the researchers are pretty confident that cockatoos  also use this method in the wild.

Because, for one, the two birds  they watched use tools in the lab had clearly had some practice. And once the researchers knew  what they were looking for, they also started noticing more  evidence of tool use in the wild. They even stumbled across an abandoned wawai fruit with a wood fragment inserted into it.

And while opening a wawai fruit might  be an ordinary task for a cockatoo, it's actually a pretty amazing feat. The use of multiple tools in a fixed  order to achieve a goal implies that cockatoos have fairly advanced psychological  skills in addition to motor skills. And it’s one more fascinating  reminder that intelligence comes in all forms across the animal kingdom.

And if you’re also looking for tools to  take your STEM skills to the next level you should check out today’s sponsor, Brilliant! They’ve upped the interactivity of  their platform to another level. Like the Pre-algebra course, where  they used interactive puzzles alongside diagrams to have your intuition lead the way.

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