World's Heaviest Moth Makes Rare Appearance at Australian School

One of the world's largest insects is difficult to spot. Weighing 30 grams (1.1 ounces), the female giant wood moth is the heaviest moth on Earth. It's also notoriously elusive, so construction workers were delighted when the critter made a rare appearance at a build site in Australia, The Guardian reports.

Workers noticed the giant wood moth while building new classrooms for Queensland's Mount Cotton state school. The property is adjacent to a rainforest, and it's hosted several iconic animals including snakes, koalas, and wallabies. But even at this school, a giant wood moth sighting is unprecedented. The builders compared the moth's size to that of a rat. Female wood moths can grow up to 15 centimeters (almost 6 inches) long, with wingspans stretching 25 centimeters (nearly 10 inches) across.

Female moths survive only a few days after reaching maturity. Their dense bodies make it difficult for them to fly, and they often climb up trees and wait for males—which are half their size—to find them. They feed on plant roots and caterpillars and rely on their fat stores to sustain them through their brief adulthood. After laying roughly 20,000 eggs, the females expire. Because of their short lifespan, few people have seen these unusual giants alive.

After snapping some photographs, the construction crew returned the giant wood moth to the nearby forest. Though the students at Mount Cotton weren't able to see the visitor in person, one class did use the moth's picture as a creative writing prompt. The monstrous bug naturally inspired some insect invasion stories, including one that ended with the teacher getting devoured by a wood moth.