Newly hatched caterpillars look helpless: they're teensy, soft and juicy, with no parent around for protection. But certain young insects, the masked birch caterpillars, are more capable than they seem. They gather in groups to keep themselves safe. To form those groups, they use a previously undiscovered language of buzzes, vibrations, head banging and butt scraping.
The species, Drepana arcuata, passes through five caterpillar life stages (called instars) on its way to becoming a li