Western Spotted Skunk, Spilogale gracilis

Western Spotted Skunks are relatively small and slender. Their ears are short and placed low on the sides of their head. They have five toes on each foot, and the claws on their front feet are sharper, recurved, and more than twice as long as those on their back feet. They are black in color with a white spot on their forehead and in front of each ear. They have a pair of dorsolateral white stripes on the anterior portion of their body beginning at the back of their head, a pair of lateral stripes in line with the spots in front of their ears, and a ventrolateral pair of stripes that begins just behind their forelegs. These anterior stripes cut off at mid-body. The posterior portion of their body has two interrupted white bands, a white spot on each side of their rump, and two more white spots at the base of their tail. The underside of their tail is white for nearly half its length and white at the tip. Sexual dimorphism is displayed with males growing slightly larger  and weighing more than the females. Males average 42.3 cm (16.7 inches) in length, including a 13.4 cm (5.3 inch) long tail, and weigh 565 g (1 lb 2 oz). Females average 36.0 cm (14.2 inches) in length, including a 12.9 cm (5.1 inch) long tail, and weigh 368 g (13 oz). 

Western Spotted Skunks are nocturnal and highly secretive. They do not hibernate, but tend to be less active during periods of cold weather. Groups of up to twenty females often den together and sleep for weeks at a time during the winter. Males tend to remain solitary and active throughout the winter. Their range usually extends within a half a mile of their den. They are agile climbers and excellent diggers, creating their dens in rocky outcrops or hollow logs. Additionally, they often live in close association with people, frequently nesting in rock fences or even attics. Mating begins in September and mate selection is done by the females. By October, breeding begins to subside. The blastula phase of the embryo floats freely in the uterus for the first one hundred and eighty to two hundred days before implanting. Gestation typically lasts for two hundred and ten to two hundred and thirty days. Litters of two to five young, called kits, are born in late April or May. After the kits are born, they remain with their mother until they are mature. Young females mature at approximately four to five months of age. They have life spans of one to two years in the wild, and more than ten years in captivity. 

Western Spotted Skunks are omnivores and their diet consists of small mammals, insects, carrion, berries, fruit, birds, bird eggs, reptiles and amphibians. In turn, they are preyed upon by Great Horned Owls, Bobcats, and domestic Dogs and Cats. Human-created causes, such as vehicle collisions, trapping, and pest control, may be the prevalent sources of mortality in many populations. Like all Skunks, the Western Spotted Skunk possesses two scent glands located on each side of their anus that spray a very foul smelling musk as an anti-predator defense. Despite having this ability, they often use it as a last resort. Instead, they often warn intruders by stamping their forefeet or making a series of hops toward the intruder, before standing on their forefeet with their tail hairs flared and anus everted. Before they spray, they place all four feet on the ground and bend their body with their head and rear directed toward the intruder. If threatened, they can also eject musk from a handstand position. Western Spotted Skunks are excellent climbers and can eject musk on an intruder from the vantage point of a post or a tree. They often aim for their attacker’s eyes, assaulting them with a yellowish colored liquid up to ten feet away and temporarily blinding them. This yellowish liquid contains mercaptans, or thiols, which are organic compounds that contain sulfur. The glands through which they emit these chemicals can modify and direct the intensity of the spray. Skunks also seem to be bothered by their smell and will not spray around their dens or each other, even when they are fighting. Young skunks do not have as much spray and their scent is weaker. 

The Western Spotted Skunk may be confused with the Striped Skunk, Mephitis mephitis, due to their similar appearances and overlapping ranges. These species can be differentiated visually. The Striped Skunk has two thin white stripes along their back and a single thin stripe on their head. They are also larger than the Western Spotted Skunk, weighing between 2.0 kg (4 lbs 6 oz) and 4.5 kg (10 lb 0 oz).

From a conservation perspective, the Western Spotted Skunk is currently considered to be of Least Concern due to their wide distribution in a variety of habitats, including human-altered ones. Humans are the main cause of mortality for this species, especially as a result of automobile roadkills. They are often trapped, shot, and poisoned during predator control tactics. Pesticides also present a significant threat over portions of their range. Their pelts represent an insignificant fraction of the modern fur trade.