Coastal Skunk Natural History

Striped skunks, Mephitis mephitis, are a common mammal found throughout the United States and southern Canada, except for some desert areas of the Southwest and some areas in the Southeast. Striped skunks utilize a variety of habitats including fields, open woodlands, wetlands, beaches, salt marshes, and agricultural fields, as well as urban and suburban areas.

Striped skunks are similar in size to domestic cats, but they have triangular, small heads. Their ears are small and rounded, and their eyes are small and black. They have five toes on the front and hind feet, and claw marks usually appear in their tracks, as their front claws are long and curved. They typically have predominantly black fur (pelage), a white stripe on the nose and forehead, and a round white patch on the top of their head (pate), which extends down their nape and splits into two white stripes on the back. The white stripes may extend into the tail, only halfway down the back, or be lacking. The tails of skunks are long and bushy. They can be all black or have varying amounts of white along the sides, in the underfur, or white only at the tip of the tail. Skunks that are entirely black, with only a white stripe on the nose and forehead and a white patch on their head, are known to have a "star" pelt. Wild skunks may also be seal brown, white, or yellow in some areas. Striped skunks are typically quiet mammals. However, they do make hissing and squealing noises when fighting and some grunting noises when foraging.

In 1996, DNA studies placed Striped Skunks in a newly created taxonomic family, Mephitidae. They share this family with the spotted, hooded, and hog-nosed skunks found in North America and the Asian stink badgers. The most distinguishing characteristic of all skunks is their ability to direct a stream or spray of musk for several meters from paired anal glands. The musk is a strong irritant to the eyes and nose and acts as a central nervous system depressant. It can cause nausea and vomiting in other mammals and temporary blindness.

Striped skunks are usually docile mammals that will tolerate humans in close proximity without showing aggression. They give many warnings to a potential victim before they spray. First, a surprised skunk will arch its back and put its tail in the air. It will then begin to stamp its front feet and sometimes lunge forward. If the potential threat does not leave, the skunk will begin to turn its hind-end towards the person or predator and begin to expose its anal glands and the bare skin surrounding them. This is the last warning a skunk gives before directing, quite accurately, a stream or fine mist of its musk at the perceived threat. Contrary to popular thought, skunks are capable of producing musk from birth. Thus, tiny skunk kits are fully capable of spraying a predator or perceived threat. However, they may not be accurate.

Fall & Winter Behavior

Striped skunks spend most of the fall putting on a substantial fat layer for the winter. As the nights get colder, skunks reduce their activity and retreat to underground dens that may be at the base of a fallen tree, under a shrub, or under the foundation of a home or building. Females will share winter dens with other females, but males usually do not tolerate other males. One male can share a winter den with as many as 11 females. These communal dens allow the skunks to benefit from each other's body heat. When nighttime temperatures are above 30 degrees F, skunks will be active for periods of time. However, when temperatures stay below freezing for long periods the skunks sleep, utilize their fat stores, and conserve energy. They are not, however, true hibernators. Thus, dog owners should beware on unusually warm winter nights. Skunks will be out and about, stretching their legs and searching for food.

In February and March, female skunks become receptive to males for breeding, and they ovulate within a few days of copulating with a male (induced ovulation). Gestation in striped skunks ranges from 59-77 days, with shortest gestation in females mating late in the season.

Spring & Summer Behavior

Females seek out solitary dens for whelping in mid-late April and early May, which they typically excavate themselves. Loss of a first litter, failure to lactate, or a false pregnancy will stimulate a second breeding period for a female in May, which results in late summer young. The young are born blind and helpless, and litter sizes range from 2 -10 (average 5.8 - 7.8 young). Experienced females have larger litters than inexperienced females. At birth, striped skunks weigh between 32 and 35 grams. They are born sparsely furred, but pigment in their skin makes their future black and white pattern discernable. Their eyes are closed at birth and open at approximately 3 weeks. If disturbed, females will move their kits to a new den. The kits do not leave the den until they are approximately six - eight weeks old, and they are typically weaned at eight weeks. Skunk kits do explore outside their den when their mother leaves on foraging trips. After six- seven weeks, the kits follow their mother in search of food and den with her in alternate dens until they are independent at anywhere from two - five months.

During the spring & summer months, skunks typically sleep in retreats above ground. They utilize shaded areas in tall grass, under shrubs, or in thickets where they curl up and sleep. While they develop and maintain a home range, skunk home ranges typically overlap. Biologists do not know much about skunk social structure. Striped skunks do not show much fidelity to above ground retreats, but will re-visit them from time to time.

Diet

While they are in the Carnivore family, striped skunks primarily eat insects and other invertebrates, including those found in the intertidal zone, as well as fruit. Primary insect foods include carabids and scarab beetles, grasshoppers, crickets, and the larvae of moths and butterflies. Skunks will eat bird eggs and nestlings when they come upon them. They are excellent mousers and have long been associated with farms and farm buildings because of the abundant supply of food available. They also eat carrion. Being dietary generalist, striped skunks will also eat human garbage, compost, and birdseed from feeders. Thus, they are oftentimes around homes in urban and suburban areas. Their primary method of foraging involves digging, and it is oftentimes a single, small hole in a lawn, leaf litter, or sand where they extract the invertebrate of their choice. They use their nose and ears to find food as they have poor eyesight beyond about 20 feet.

Striped skunks live as long as 10 years in captivity, but rarely live beyond 5 years in the wild. Disease is an important source of mortality for striped skunks. Epizootics of rabies, distemper, pneumonia and leptospirosis take a heavy toll on skunk populations in some years and many skunks succumb to heavy parasite loads in the spring. In Massachusetts, their predators include cars, great-horned owls, coyotes, dogs, and foxes. However, predators do not typically limit skunk populations. While we do not have any native skunk predators on the island, automobiles and nuisance skunk removal practices kill more skunks than predators would in any given year.

Coastal Skunk Ecology Research Project - Antioch University New England
Luanne Johnson
PO Box 557
Edgartown, MA 02539
(508) 685-2578
Web page: http://www.antiochne.edu/es/phd/ljohnson.cfm

References

Verts, B.J. 1967. The Biology of the Striped Skunk. University of Illinois Press, Urbana, 288 pp.
Wade-Smith J., and B. J. Verts. 1982. Mephitis mephitis. Mammalian Species 173:1-7.