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Alabama Beach Mouse -- Biology

Alabama Beach mouse. Credit: USFWS

Alabama Beach mouse. Credit: USFWS

The Alabama beach mouse (ABM) is perhaps most truly representative of coastal dune habitat in Baldwin County, Alabama. This mouse is one of several subspecies of old field mice which live only in coastal sand dune areas. Living isolated from other beach mice for thousands of years has allowed each subspecies to develop its own slightly unique characteristics suited to its particular beach environment.

Other beach mouse species along the northern coast of the Gulf of Mexico include: Perdido Key beach mouse, Choctawhatchee beach mouse, Santa Rosa beach mouse, and St. Andrews beach mouse. They differ from the ABM and each other in coloration and body size.

The ABM was federally listed as endangered in 1985 because of impacts to its habitat.

Being nocturnal animals, they have large eyes and big ears to help them as they leave their burrows at dusk and remain active at night. They are much less active on moonlit nights though to avoid becoming a late night snack for predators.

Beach mice are small…about 4-5 inches long, including their tail, and weigh around 12.5 grams (less than the weight of three nickels). In the wild they may live 9 months to a year. Female beach mice usually bear around four pups per litter with a 23-day gestation period. A female beach mouse can breed again within 24 hours of giving birth.

Recent research indicates that beach mice are often monogamous and the family unit may utilize more than 10 burrows within their home range.

Live trapping studies have shown that the numbers of beach mice fluctuate greatly, as does the geographical area they occupy. These sometimes drastic changes to the status of ABM populations are thought to be related to the abundance of food and cover and other factors.

During times of high population numbers, ABM can be found in relatively large numbers in all suitable habitat from the primary-secondary dunes inland to adjacent escarpment and interior scrub oak dune areas.

During unfavorable habitat conditions, such as after tropical storms or during droughts, the ABM may be restricted to smaller areas within their habitat. Such conditions may cause the ABM to be either absent or at very low numbers because small isolated populations may be lost as a result of a number of chance variations in environmental conditions or population factors; protection of habitat and connections between patches is very important.

ABM feed primarily on seeds and insects. Some of these plants include sea oats, ground cherry, dune spurge, bluestem, evening primrose, beach pea, jointweed, seashore elder, seaside pennywort and the various acorns found in the interior "scrub" habitat.

Unlike the house mouse, beach mice are not known to live in buildings, cars, garages. Nor do they frequent garbage sites.

While population fluctuations are a normal part of beach mouse life, there are a number of threats which continue to challenge the persistence of ABM. These include both natural and man-made threats.

Feral and/or free-roaming cats are thought to be at least partly responsible for the loss of ABM on Ono Island and are considered to be a factor in the extinction of the pallid beach mouse on the Atlantic Coast of Florida.

Natural predators…like the coachwhip snake or owls...are more of a concern when beach mice are vulnerable, such as following storms or during periods of low populations.




Last updated: May 5, 2021