The Seatco lived in wild places just like animals and would steal fish from humans. Instead of a spoken language, they whistled for communication and enchanted humans with this whistling,; they were known to steal human children to become their slaves so children were warned not to stray too far into the wilderness. If one of the Seatco were killed they would remember who had done it and one day take revenge. They ventured to go hunting but never crossed water.
One report details how a Native American boy once told a story from his grandfather in the mid 19th century. According to the boy's grandfather, a group of Native Americans captured a Seatco boy, they witnessed how this boy was nocturnal and captured fish, hunted deer and collected wood for fire, the Seatco eventually came to retrieve their boy. Their whistling scared the Native American people away, leaving the boy unattended. The boy then reunited with his family and the Seatco were not seen by these Native Americans again.