Beach Mice

I would love to see a beach mouse, but chances of seeing these big-eared, dark-eyed animals in the wild are slim. Beach mice blend in well with their sandy habitat, they are nocturnal, and they are rare. There are seven subspecies of old field mice (Peromyscus polionotus) that live only on sand dunes in Florida and Alabama. Except for the Santa Rosa beach mouse, which is thriving, they are all listed as threatened or endangered. There was an eighth type of beach mouse, the Pallid beach mouse from Volusia and Flagler Counties, but it has not been seen since 1959.

Beach mice live in burrows at the base of sea oats on sand dunes. A mouse-sized hole leads down a narrow, four-foot long tunnel to a chamber where mice sleep during the day and store the seeds they collect at night. Beach mice build their burrows with an escape hatch in the main chamber. If an intruder, possibly a snake, comes through the main tunnel, the mice can burst through a thin layer of sand at the mouth of the hatch and scamper to safety. The mice build and maintain several burrows in their home territory.

Beach mice can live for nine months to a year and are sexually mature at eight weeks. The mice mate for life, a rare habit among mammals. Two to four pups are born after a twenty-two day gestation. The mother stays with the pups in the burrow for a couple weeks until the young are ready to leave the nest. During this time the father forages for food and keeps the mother fed. Winter is peak breeding time for the beach mouse, but if food is plentiful and conditions are good, the mice can reproduce year round.

Despite their robust love life, beach mice are rare. Much of their habitat has disappeared or has been cut up into small, isolated parcels as sand dunes and sea oats are replaced with condos and sod. Hurricanes can destroy beach mice habitat too. In October, Hurricane Michael plowed through sand dunes that were home to beach mice in Florida’s panhandle. Luckily, biologists have seen mouse tracks and other signs of mouse life which tell them that some of the mice  survived. Cats and sometimes foxes are another fierce threat to beach mice. Beach mice populations can bounce back after predation by native hunters like raccoons, owls, snakes and great blue herons, but cats are just too good at catching mice.

We can help the beach mouse by protecting sand dunes and keeping cats away. Stay on designated paths to the beach to avoid trampling dune vegetation. Keep cats inside, and don’t encourage stray cats to stay at the beach by feeding them there. Finally, keep lights from shining on beaches at night because beach mice won’t come out of their burrows to collect food if it’s light outside.

Mollie Getson, Conservation Coordinator for Brevard Zoo says: “Biologists have had wonderful success collecting beach mice from areas when they are threatened, and either relocating them or breeding them under human care to create an assurance population.” Brevard Zoo has been successfully raising beach mice since 2007. In 2010, forty-eight zoo-born mice were introduced to Perdido Key. Brevard Zoo, along with Santa Fe Teaching Zoo, Palm Beach Zoo, the US Fish and Wildlife Service and Florida Wildlife Conservation Commission are all working together to bring mice back to the beach.

Why bother about an animal we’ll probably never see? Because we love the beach, and beach mice are (or should be) part of the beach. The more we know about our beaches and oceans, the more eager we are to take care of our beaches, oceans and the animals we share them with. Want another good-steward tip? Grab a clean, used plastic bag from the BlueTube at your shore, pick up trash and throw it away. Put your extra bags in a BlueTube and help others keep the beach clean and keep plastic out of the ocean. If your favorite stretch of shore has no BlueTube, sponsor one there.