A tent caterpillar is a type of caterpillar that builds large, silky webs in the branches of trees, especially fruit trees like cherry and apple. These webs look like messy white tents stretched across the forks of branches, which is how the caterpillar got its name. Dozens or even hundreds of tent caterpillars live together in one web, crawling out during the day to eat leaves and returning to their silk tent at night for protection.

Tent caterpillars can strip a tree of its leaves in just a few weeks if there are enough of them. While this looks alarming, healthy trees usually recover and grow new leaves. Tent caterpillars eventually transform into small brown moths. They're different from similar-looking caterpillars called fall webworms, which build their webs around leaves at the ends of branches rather than in the forks of branches.

If you see a tent caterpillar web in early spring, you're witnessing one of nature's most effective survival strategies: living in groups provides warmth and protection from predators. The silk tent even acts like a greenhouse, warming up in the sun and keeping the caterpillars cozy on cool spring mornings.