Silk

Silk did not emerge from human ingenuity. It emerged from an insect—a small, blind, flightless moth that had evolved to spin a cocoon from a single continuous filament of protein. What humans invented was the recognition that this filament could be unwound and woven into fabric, and the infrastructure to farm the moths at scale.

The story begins with Bombyx mori, the domesticated silkworm, whose wild ancestor Bombyx mandarina still lives on white mulberry trees in China. At some point during the Neolithic Yangshao culture, between 5000 and 3000 BCE, people in the Yellow River valley began noticing that certain caterpillars produced remarkably fine, lustrous thread. A silk cocoon found at Xia County, Shanxi, cut in half by a sharp knife, dates to between 4000 and 3000 BCE—direct evidence of deliberate cocoon processing rather than accidental discovery.

The adjacent possible for silk production required an unusual convergence of conditions. The mulberry tree had to grow in sufficient density to support caterpillar populations. The climate had to be warm enough for multiple silkworm generations per year but not so hot that cocoons rotted before harvest. People had to possess the patience to nurture worms through their lifecycle and the manual dexterity to unwind filaments averaging 300 to 900 meters in length from a single cocoon.

The earliest physical evidence of silk fabric comes from the Liangzhu culture in Zhejiang province, where fragments, ribbons, and threads dated to around 3000 BCE show weaving techniques already well-developed. An ivory cup carved with a silkworm design, recovered from archaeological contexts 6,000 to 7,000 years old, suggests the insect held cultural significance long before its product became a trade commodity.

Over thousands of years of selective breeding, the wild Bombyx mandarina transformed into the domestic Bombyx mori—a creature so thoroughly adapted to human care that it can no longer fly, cannot eat without assistance in some strains, and will starve if not supplied with mulberry leaves. This is mutualism carried to its logical extreme: an organism that traded independence for guaranteed reproduction, becoming an extension of human manufacturing rather than a wild species.

China maintained a monopoly on silk production for roughly three thousand years—one of the most successful trade secrets in history. The penalty for smuggling silkworm eggs or mulberry seeds out of the empire was death. This monopoly made silk literally worth its weight in gold along the trade routes that would eventually bear its name. The Silk Road was not metaphorical; camel caravans carried bolts of Chinese silk across Central Asia to Mediterranean markets where it commanded prices reserved for precious metals.

The secret eventually leaked. According to one tradition, a Chinese princess smuggled silkworm eggs hidden in her headdress to Khotan around 440 CE. By 552 CE, Byzantine missionaries had carried silkworms to Constantinople, breaking the Chinese monopoly after more than two millennia. But path dependence had already locked in Chinese techniques: the methods of feeding, harvesting, reeling, and weaving that spread westward were fundamentally the same as those developed in Neolithic Yangshao villages.

The cascade from silk production extends into unexpected domains. The Jacquard loom, invented in 1804 to automate silk weaving patterns, used punched cards to control its operation—the same principle that Charles Babbage would later adapt for his Analytical Engine. The machine that wove silk became a conceptual ancestor of the computer.

By 2026, China still produces roughly 75% of the world's silk, more than 150,000 metric tons annually. The Bombyx mori caterpillars spinning cocoons in industrial facilities are descendants of the same lineage that Yangshao farmers first nurtured 8,000 years ago. The conditions that made silk production possible then persist now: mulberry trees grow, caterpillars spin, and humans harvest the thread.