Dear WTB, we live in northern California, in the foothills north of Sacramento (Penryn). On our walks to the local pond we have been finding a lot of these caterpillars along the trail. Can you help us learn what they are? Thank you,
Jack (6) and Macy (4).
Hi Jack and Macy,
This is a Pipevine Swallowtail Caterpillar. They feed on both native and cultivated pipevine. If provoked, the caterpillar has an interesting defense mechanism. A forked orange scent gland called the osmetrium emerges, looking like a forked horn. The caterpillar then emits a foul odor.