Where American Dog Ticks Lurk. The Surprising Places These Pests Call Home

Introduction

The American dog tick (Dermacentor variabilis) is a common species of tick found throughout much of North America. Also known as the wood tick, it gets its name because it is frequently found on dogs, but also feeds readily on humans and other mammals.

American dog ticks are three-host ticks, meaning they feed on three different hosts during their lifetime. Adult females lay eggs on the ground after feeding, and these eggs hatch into larvae that feed on small rodents and birds. After molting into the nymph stage, they feed on medium-sized mammals like raccoons, foxes and opossums. Finally, adults feed primarily on larger mammals like dogs, livestock and humans before laying their eggs to start the cycle again.

This tick can transmit diseases when feeding, such as Rocky Mountain spotted fever and tularemia. While not as common a disease vector as deer ticks, prevention and awareness of American dog ticks is still important for pet and human health.

This article will provide an overview of the geographic range, life cycle, habitats, seasonality, and disease risks associated with the American dog tick.

Geographic Range

the american dog tick is primarily found in the eastern and southcentral united states.

The American dog tick is widely distributed in the eastern and southcentral United States, extending as far west as Texas and Nebraska (CDC, 2022). According to the University of Florida, this species is found “throughout most of North America east of the Rocky Mountains and south of central Canada” (UF/IFAS, 2008). More specifically, the American dog tick can be found in areas east of the 103rd meridian, which includes the following states:

Maine, New Hampshire, Vermont, Massachusetts, Connecticut, Rhode Island, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, West Virginia, Kentucky, Tennessee, North Carolina, South Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana, Arkansas, Missouri, Oklahoma, Kansas, Nebraska

American dog ticks are most abundant in the southeastern United States. The tick can also be locally abundant in areas of California like San Diego and Los Angeles counties (TickEncounter, n.d.). However, they are not endemic west of the Rocky Mountains.

Preferred Habitats

American dog ticks thrive in a variety of habitats including forests, grasslands, and marshes (American Dog Tick – TickEncounter). They prefer areas with tall grasses and brush that provide shade and moisture.

Forests with leaf litter or grassy undergrowth offer ideal conditions for American dog ticks (American Dog Tick Diseases, Bites, Information: PestWorld). The shade and humidity allow them to avoid drying out.

Marshes and wetlands also provide suitable habitats as the vegetation retains moisture that ticks need to survive (American Dog Tick). Areas along marsh edges and wetland banks tend to have high tick populations.

Seasonality

American dog ticks are most active from late spring through summer when the weather is warmer. According to the University of Rhode Island TickEncounter Resource Center, adult American dog ticks become active in the spring when temperatures average around 45-50°F. They remain active through the summer months. The peak activity period for American dog ticks is usually May, June and July (University of Rhode Island).

American dog tick nymphs are also most active in the late spring and early summer. After hatching from eggs in the summer months, the tiny larval ticks feed on small rodents and birds. They then overwinter and molt into nymphs in the spring, seeking warm-blooded hosts like dogs, deer, and humans. Nymphal activity peaks in May and June (University of Rhode Island).

Adult activity declines in August, and American dog ticks generally become inactive once temperatures drop below 45°F. Cold winter temperatures cause them to go dormant until the next spring (University of Florida).

Life Cycle

the life cycle of the american dog tick has four stages: egg, larva, nymph, and adult.

The life cycle of the American dog tick has four stages: egg, larva, nymph, and adult. The adult female lays around 5000 eggs on the ground in the spring and summer. The eggs hatch into larvae in about a month. The tiny larval ticks then feed on small rodents and birds for about a week before dropping off and molting into nymphs. The nymphs overwinter in sheltered areas and become active in the spring. They feed on larger rodents, raccoons, opossums, skunks, and dogs for 3-5 days before dropping off. After another molt they become adults. Adult ticks feed and mate on large mammals like deer, dogs, coyotes, and humans. After feeding for 4-10 days, the engorged female drops off to lay her eggs, completing the life cycle.

At each stage, the American dog tick requires a blood meal from a host animal to develop to the next stage. Larvae and nymphs tend to feed on small rodents, while adults prefer larger animals. Dogs are one of the tick’s primary hosts, which is how it gets its name. The tick can also spread diseases like Rocky Mountain spotted fever, tularemia, and ehrlichiosis to dogs and humans through its bites.

Climate Factors

climate factors like temperature and humidity significantly influence the range and abundance of american dog ticks.
American dog ticks thrive in temperate climates and are most active when temperatures are above 45°F. They prefer humid conditions, as low humidity can cause desiccation and death. Hot and dry weather in summer can reduce tick populations, while rainy springs support population growth (https://academic.oup.com/jme/article/59/2/700/6455005).

Ticks survive cold winters by going dormant beneath leaf litter. Milder winters due to climate change allow more ticks to survive and extend their active seasons. Warmer temperatures also speed up their life cycle. Studies show the geographic range of American dog ticks expanding northward as climate changes (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5877023/).

Overall, the abundance and range of American dog ticks is heavily influenced by temperature, humidity, and weather patterns. Climate change may support larger populations over broader areas. Monitoring climate factors provides insight into tick distribution and disease risk.

Host Animals

The American dog tick feeds on a variety of mammal hosts during its lifecycle, with deer and mice being among the most common. According to the University of Rhode Island TickEncounter Resource Center, deer are the primary host for adult American dog ticks, which will wait on low vegetation for a deer to brush by so they can attach (https://web.uri.edu/tickencounter/species/dog-tick/). White-tailed deer are most frequently parasitized, but American dog ticks will also feed on elk, moose, coyotes, and other mammals.

deer and small rodents like mice are among the most common hosts for american dog ticks.

The immature stages of American dog ticks typically feed on small rodents like mice and voles. According to the University of Florida Entomology Department, larvae and nymphs primarily feed on white-footed mice, meadow voles, and other small mammals as they develop (https://entnemdept.ufl.edu/creatures/urban/medical/american_dog_tick.htm). These small rodents allow the juvenile tick stages to complete their lifecycles so they can molt into the next stage.

Other mammals like raccoons, skunks, opossums, squirrels, rabbits and hares may also serve as hosts, according to the Connecticut Agricultural Experiment Station (https://portal.ct.gov/-/media/CAES/DOCUMENTS/Publications/Fact_Sheets/Entomology/AmericanDogTickFSpdf.pdf). Domestic animals like dogs and cats can also be parasitized by American dog ticks. Humans are incidental hosts and are sometimes bitten as well.

Disease Risks

Two of the most well-known diseases spread by the American dog tick are Lyme disease and Rocky Mountain spotted fever (RMSF). Lyme disease is caused by the bacterium Borrelia burgdorferi and RMSF is caused by the bacterium Rickettsia rickettsii. Both diseases can be serious if not treated promptly with antibiotics.

According to the CDC, the American dog tick is considered a major vector for RMSF in the eastern and north-central United States (CDC). RMSF begins with symptoms like fever, headache, nausea, vomiting, and muscle pain. A spotted rash usually develops 2-4 days after the onset of fever. RMSF can be fatal if not treated early with the antibiotic doxycycline.

While the American dog tick can transmit Lyme disease, it is not considered a major vector. The blacklegged tick (or deer tick) is the primary Lyme disease carrier. Initial symptoms of Lyme disease include fever, chills, headache, fatigue, muscle and joint aches, and swollen lymph nodes. An expanding “bull’s-eye” rash often occurs at the site of the tick bite. Without antibiotic treatment, Lyme disease can spread to the joints, heart, and nervous system.

Prevention

There are several ways to prevent and avoid bites from American dog ticks. According to the CDC, using EPA-registered insect repellants like DEET, picaridin, IR3535, or oil of lemon eucalyptus can help repel ticks when outdoors (https://www.cdc.gov/ticks/avoid/on_people.html). Wearing long sleeves, long pants, hats, and closed-toe shoes when in wooded, brushy, or grassy areas can create a barrier against ticks. Tucking pant legs into socks or boots and tucking shirts into pants help keep ticks on the outside of clothing.

Performing daily tick checks after being outdoors is also critical for both pets and people. Carefully examine skin and hair, under arms, in and around ears, inside belly button, behind knees, between legs, around waist, and especially in hair. Finding and removing ticks quickly can prevent possible infections. Promptly remove any attached ticks with tweezers.

For yards and properties, keeping grass mowed, clearing tall weeds and brush, creating borders between woods and lawns, and placing wood chips or gravel between lawns and wooded areas can help reduce tick habitats. Using pesticides specifically labeled for ticks around yards can also control tick populations. For pets, products containing fipronil, s-methoprene, or sarolaner can repel and kill ticks.

Conclusion

American dog ticks are most common in the eastern and southcentral United States, though their range stretches across much of the country. They prefer wooded, humid environments and are especially active in the spring and summer months. Ticks go through four life stages, each requiring a blood meal, often from small rodents or other mammals. The population of ticks in an area depends on climate conditions suitable for their development. While pets and humans can contract diseases from tick bites, risks can be minimized through preventative measures like avoiding tall grasses, using repellents, and checking for ticks after potential exposure. In summary, being aware of the habitat and behavior of American dog ticks allows pet owners and outdoor recreators to take steps to prevent tick bites and associated illnesses.

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