Earthworms lay eggs inside amber-colored cocoons their bodies produce. Premature eggs that come out of their protective cocoons will shrivel and die. Eggs hatch inside the cocoon, and the cocoon itself becomes a protective egg for the baby worms inside. After about three weeks, each cocoon generally hatches between two and 20 baby earthworms. Some species of earthworm can produce up to 80 cocoons per year. Earthworms can live for up to eight years, but most are eaten or killed long before they become old. The average lifespan of an earthworm is less than one year.
Hold a magnifying glass over the suspected earthworm cocoon. Do not allow sunlight to enter the magnifying glass and project on to the cocoon for any length of time. Doing so could cause damage to the cocoon or cause death to the baby earthworms inside. Instead, look through the magnifying glass and adjust it so the cocoons appear magnified.
Gauge the size of the suspected cocoon. Earthworm cocoons are generally about 1 cm long.
Identify the color of the suspected cocoon. Earthworm cocoons are white when they are new and turn amber in color after several hours.
Determine the shape of the suspected cocoon. Earthworm cocoons are generally shaped like lemons, although some are teardrop-shaped.