Big monarch caterpillars don’t avoid toxic milkweed goo. They binge on it

The plant sap is a sticky deathtrap for young larvae. Older lab larvae guzzle it from pipettes

A photo of a monarch butterfly caterpillar on the underside of a leaf.

About to binge-drink from a milkweed plant, a nearly grown monarch butterfly caterpillar positions itself to bite into a leaf stalk and lap up the toxin-rich plant fluid that will bleed out.

Anja Betz

Maybe science has misunderstood the dining style of big monarch butterfly caterpillars.