To fishermen and seafarers, catching sight of the animals frolicking in the waves or loafing on the beaches was considered to be an omen of good fortune. Because of their trusting nature they were easy prey for hunters and fishers using clubs, spears and nets. The pelts were used to make tents and were said to give protection against Nature's more hostile elements, especially lightning. The skins were also made into shoes and clothing, and the fat used for oil lamps and tallow candles. Because the animal was known to sleep so soundly, the right flipper of a seal, placed under the pillow, was thought to cure insomnia.
Evidence suggests that the species was severely depleted during the Roman era.
Following the fall of the empire, a reduction in demand may have allowed the monk seal to stage a temporary recovery, but not to earlier population levels. Commercial exploitation peaked again in certain areas during the Middle Ages, effectively wiping out the largest surviving colonies. The massive disruption of two world wars, the industrial revolution, a boom in tourism and the onset of factory fishing all contributed to the Mediterranean monk seal's decline - William M Johnson . At one time, the Mediterranean monk seal occupied a wide geographical range. Colonies were found throughout the Mediterranean, the Marmara and Black seas.