The Bone Collector Caterpillar

Most caterpillars eat leaves. This one lives in spider webs, feeds on trapped insects, and wears the remains of the dead as camouflage.

In the mountain forests of Oʻahu, scientists discovered one of the strangest caterpillars on Earth. Known as the bone collector, this rare Hawaiian species survives inside spider webs by moving carefully, scavenging what the spider leaves behind, and blending into the debris of the web itself. Reporting on the 2025 discovery described it as a newly identified carnivorous Hyposmocoma caterpillar with a very limited known range and fewer than 62 observed individuals over about 20 years.

This book takes readers into the hidden world of the bone collector caterpillar and explains why it shocked scientists. You will learn how it builds its strange case, how it survives inside a predator’s trap, why carnivorous caterpillars are so rare, and how island evolution in Hawaiʻi can produce creatures unlike anything found anywhere else. The book also explores why this species may be so vulnerable in the modern world and what its story teaches us about adaptation, rarity, and conservation. The core facts about the species line up with the discovery coverage and the scientific paper describing its web-dwelling, insect-part camouflage and unusual feeding behavior.

If you enjoy natural history, strange but true science, and stories about the hidden extremes of evolution, this short nonfiction read will show you one of the most astonishing small creatures ever found in Hawaiʻi.