Caye Caulker has a fascinating history. Originally, the island was inhabited by Maya peoples and later became home to Mestizo families who fled the violent Caste War of Yucatán in the mid-1800s. Many of the island’s founding families settled there around the 1840s–1870s, and their descendants still live there today. Fishing, boat-building, and coconut farming were the traditional livelihoods before tourism became important.

The famous “Split” — the channel that divides the island into North Caye Caulker and South Caye Caulker — is tied to Hurricane Hattie in 1961.

For many years, people believed Hurricane Hattie literally split the island in half overnight on October 31, 1961. Hattie was an extremely powerful Category 5 hurricane that devastated Belize and killed hundreds of people.

But the fuller story is a little more interesting:

• Hurricane Hattie did tear through a very narrow, low section of the island and opened a small natural cut or shallow channel.
• After the storm, local residents manually deepened the passage so small boats and dugout canoes could pass through more easily. One local account says villagers hand-dredged it after the hurricane left only a few inches of opening.
• In later years — especially during the 1970s and afterward — dredging and natural tidal erosion widened and deepened it dramatically.

So the answer is:

• The original opening began during Hurricane Hattie in 1961.
• The large “Split” visitors see today became much bigger over time because humans enlarged it and tides kept eroding it wider.