The spicebush swallowtail caterpillar is, well, it’s sure something. We’re going to say it’s creepy, thanks to those fake eyes and swollen-looking head. As it turns out, there’s a perfectly good reason the spicebush swallowtail caterpillar looks like this, and it’s all about self-defense. It doesn’t just defend itself by wearing a pair of false eyes, tough. It also pretends to be a snake, complete with a forked organ that looks like a snake’s tongue.
Back in 2020, the National Park Service (NPS) shared a photo of this bizarre caterpillar (aka “Caterpie,” because it looks just like a Pokemon with that name), explaining why it looks the way it does. NPS also describes the evolution of the caterpillar’s look from just plain weird to super creepy.
“[The] Spicebush Swallowtail Caterpillar has many abilities including adaptability, color change, illusion, leaf guard, mimicry, and poison touch,” NPS writes in its caption. “In its early stages, it resembles a bird dropping, how nice, and is found exposed during the day on the upper side of the leaves. After molting the caterpillar turns green and displays the snake’s head mimicry, with large spots giving the appearance of a snake’s head.”
Here’s a swallowtail in its green form, showing off snake-head mimicry:
Those false eye spots look like real eyes to predators (and unsuspecting humans). Predators see that thing and think, no thank you. This particular swallowtail species then changes from green to orange or yellow, before transforming itself into a chrysalis and metamorphosing into a pretty regular-looking butterfly.
“[These] mimics can be poisonous and distasteful to predators,” NPS says. (So it’s not all a complete ruse.)
Here’s a spicebush swallowtail in its orange form:
Creepy Snake Vibes Leveled Up
And now for the real fun. Swallowtails, when they’re mad, rear up like a snake and stick out an orange, forked organ that looks an awful lot like a snake’s tongue. In one TikTok video of a two-tailed swallowtail, you can see the caterpillar start to do the snake thing after one poke. After two pokes, it’s sticking out its Y-shaped organ called an osmeterium.
And its osmeterium is stinky, too. That foul odor will scare off predators if the snake act doesn’t.
What do you think? Cool, creepy, or both?