But it existed.

The channel has always existed.

There is no period within the last two million years — no time when any human being was alive anywhere on Earth — during which Santarosae was connected to the mainland by dry land.

The minimum width of that channel during the terminal Pleistocene, when sea level was lower, has been estimated at roughly 4.5 to 7 miles — a body of open ocean, even at its narrowest.

More recent reconstructions using high-resolution bathymetric and sediment data have refined the estimates, but the basic conclusion is unchanged: reaching Santarosae required crossing open water.