Barrier islands range from sparse to rich in faunal diversity. The differences usually reflect island size and shape (including elevation and width), habitat variety, the presence of fresh water, island age, distance from the mainland, and human activity.

Historically, Sanibel’s wildlife was relatively diverse for a young island that is less than 5,000 years old, given its size and distance from the mainland.

“Sanibel has an impressive list of fish, amphibians, reptiles, and mammals, enhanced in some ways by the alteration of the Sanibel Slough for mosquito control, the digging of residential lakes, and the weir system that holds fresh water on the island,” says SCCF Wildlife & Habitat Management Director Chris Lechowicz.

“Over time, species have been gained and lost on the island, either from natural causes, such as hurricanes, or man-made causes, such as development and traffic,” he adds.

The Sanibel rice rat is endemic to Sanibel, which means it exists only on the island.

Some species, such as the Sanibel Island rice rat (Oryzomys palustris sanibeli), declined as closed-canopy forest increased and grasslands decreased, while other species, such as the Florida softshell turtle (Apalone ferox) and American alligator (Alligator mississippiensis), became more common in newly created permanent waterbodies.

It’s hard to imagine that white-tailed deer (Odocoileus virginianus), striped skunks (Mephitis mephitis), minks (Mustela vison), and gray foxes (Urocyon cinereoargenteus) were part of Sanibel’s fauna within the last century or so. Their extirpation was mainly due to overhunting in the early 1900’s and likely road mortality in later years. However, the succession of habitat caused by fire suppression and altered hydrology may have played a role as well.

“Barrier islands are dynamic and constantly changing, not just in shape, but also in extant species composition, both native and exotic,” says Lechowicz.

Ever-Changing Species on Sanibel

Some species, such as the Virginia opossum (Didelphis virginiana), were not known on Sanibel until shortly after the causeway opened in 1963. They very likely walked across.

Virginia opossums weren’t seen on the island after Hurricane Ian until one recent sighting.

Numerous exotic lizards arrived on the island after Hurricanes Charley (2004) and Ian (2022), carried in with nursery stock from the east coast during the mass replanting of native vegetation.

In 2011, coyotes (Canis latrans) and one black bear (Ursus americanus floridanus), which was removed a year later, found their way to Sanibel either by swimming across or walking across the causeway.

In June 2025, a cottontail was sighted on the east end of Sanibel. Note the white, fluffy tail that distinguishes it from the marsh rabbit.

Eastern cottontail rabbits (Sylvilagus floridanus) were documented on Sanibel after Hurricane Ian (2022) and now are sympatric (existing within the same geographical area) with the resident marsh rabbits (Sylvilagus palustris).

“Other species will likely find their way to the island in the future through similar means,” adds Lechowicz.

Please report your wildlife sightings here or email photos to sccf@sccf.org.

Photo of white-tailed deer at top of articl...

Sanibel-Captiva Conservation Foundation

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