Around 3000 B.C., the sands of Captiva started to erode, resulting in the eventual formation of Sanibel Island. The Gulf of Mexico waters were eight feet lower than they are today. It is said that the first inhabitants of Captiva were the Calusa Indians. The population of the Calusa is believed to have reached as many as 50,000 people. "Calusa" means "fierce people", and they were described as a war-like people. The Calusa Indians were resistant to colonization and attacked any explorers who came into their territory. Calusa Indians built their houses on stilts without walls. They wove palmetto leaves together to build roves (twisted strands of fibers). The Calusa Indians fished for food on the coast, bays, rivers, and waterways. They did not farm. “The men and boys of the tribe made nets from palm tree webbing to catch mullet, pinfish, pigfish, and catfish. They used spears to catch eels and turtles. They made fish bone arrowheads to hunt for animals such as deer. The women and children learned to catch shellfish like conchs, crabs, clams, lobsters, and oysters.” The Calusa Indians used the shells on the island for utensils, jewelry, tools, weapons, and ornaments.