Understanding the American dog tick (Dermacentor variabilis)
Learn how to identify, manage, and protect against American dog ticks.
Content Updated: February 26th, 2025
The American dog tick, also known as Dermacentor variabilis, is one of the most common tick species in the United States, thriving in the Eastern part of the United States. These dog ticks are not just a nuisance, they can also pose serious health risks to both humans and pets. Knowing the dog tick’s habits, habitat, and potential health threats can help you take steps to safeguard your home and loved ones.
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Identifying American dog ticks
American dog ticks and tick-borne diseases
American dog tick prevention and control
Identifying American dog ticks
All ticks share common traits that make them identifiable, such as their oval shape, eight legs, and their ability to swell dramatically after feeding. The American dog tick, however, has distinct features that set it apart. Adult ticks have a reddish-brown body with whitish or grayish markings on their backs, while females are larger than males and can swell significantly after feeding. In contrast, nymphs and larvae are much smaller and harder to spot due to their size.
Although often called a wood tick in some regions, the American dog tick and wood tick are the same species. These ticks are commonly found in grassy fields, trails, and other outdoor spaces where they can latch onto hosts such as dogs, deer, or small mammals.
Life cycle
The life cycle of ticks consists of four stages: egg, larva, nymph, and adult. The American dog tick follows the same pattern, with each stage uniquely adapted for survival. Like many ticks, the dog tick can survive for extended periods without a host, relying on its ability to enter a dormant state. In fact, adult American dog ticks can live for up to two years without feeding, making them resilient pests.
Here's a breakdown of the American dog tick’s life cycle stages:
Egg stage
Female American dog ticks lay thousands of eggs in secluded outdoor locations, beginning the first phase of their life cycle. These eggs have distinct characteristics and specific conditions for hatching.
Appearance: Tiny, round, and dark brown.
Duration: Eggs hatch within 1 to 2 weeks after being laid, depending on environmental conditions.
Larva stage
After hatching, larvae emerge as six-legged “seed ticks” that must find a host to take their first blood meal. This stage is defined by their small size and limited ability to survive without feeding.
Appearance: Small, six-legged, and light brown.
Duration: Larvae feed on a host for a few days before molting into nymphs, a process that can take several weeks to months, depending on host availability.
Nymph stage
Once larvae molt, they become nymphs, entering a stage where they feed on smaller hosts to prepare for adulthood. Nymphs can survive several months without feeding but require a blood meal to molt into adults.
Appearance: Slightly larger and darker brown than larvae with eight legs.
Duration: This stage can last a few months to nearly a year as the nymph feeds on whatever it can to gain the energy it needs to turn into an adult.
Adult stage
In their final stage, adult dog ticks seek larger hosts like dogs, deer, or humans to feed on, reproduce, and complete their life cycle. Adults are the most visible stage and have the greatest impact on hosts.
Appearance: Reddish-brown with whitish or grayish markings on the back. Females are larger than males and can swell significantly when engorged.
Duration: Adults can live for up to two years, with males dying after mating and females laying eggs before completing their life cycle.
Knowing the life cycle of the American dog tick is crucial for managing and preventing infestations. Each stage presents unique challenges, but recognizing their behaviors and survival strategies empowers you to take proactive steps to protect your family and pets.
Habitat
American dog ticks are commonly found in most states east of the Rocky Mountains, as well as in some parts of western states, including California, Idaho, and Washington. They thrive in grassy fields, wooded areas, and along trails where hosts are abundant. These ticks are more prevalent in rural or secluded areas near homes and buildings but rarely live indoors. When found inside, it is typically because they’ve latched onto pets like cats or dogs. By knowing their preferred habitats, you can better understand where you’re most likely to encounter these pests and take steps to avoid them.
Diet and behavior
Like all ticks, the American dog tick is a blood-feeding ectoparasite that targets mammals throughout its life stages. During the larva and nymph stages, dog ticks feed on small mammals like mice and voles, while adults prefer larger mammals like dogs, deer, raccoons, and occasionally humans. Each stage of the tick’s life cycle requires a blood meal to progress, with adult females needing to gorge on blood to produce a single batch of thousands of eggs. Despite laying so many eggs, only a small number survive to maturity.
American dog ticks are most active during the spring and summer months, especially from April to June, and are commonly found in wooded areas and near bodies of water where animals gather. During feeding, they insert only their mouthparts into the host’s skin and secrete saliva that has anticoagulants to prevent clotting, ensuring a continuous blood flow.
American dog ticks and tick-borne diseases
Ticks are known to spread illnesses to humans and animals through tick bites. The American dog tick is no different. While Lyme disease is not associated with this type of tick, it is a carrier of other serious illnesses. Here are the primary American dog tick diseases to be aware of:
Rocky Mountain spotted fever (RMSF): A bacterial infection that causes symptoms like fever, headache, muscle pain, nausea, and a spotted rash that usually begins on the wrists and ankles before spreading. RMSF needs to be treated quickly with antibiotics because it can lead to severe complications or death if left untreated.
Tularemia: A bacterial disease that leads to symptoms like fever, skin ulcers, swollen lymph nodes, and fatigue. Though serious, tularemia is treatable with antibiotics when diagnosed early.
Tick bite paralysis: A rare condition caused by a toxin in the tick’s saliva, resulting in gradual paralysis that starts in the legs and progresses upward. If untreated, it can affect respiratory muscles, but removing the tick typically resolves the paralysis quickly.
A bite from an American dog tick often appears as a small, red, raised bump on the skin. In some cases, redness, swelling, or irritation may develop around the bite site. Symptoms such as itching, localized pain, or a burning sensation are also common. If you experience flu-like symptoms, joint pain, or a distinctive spotty rash following a bite, seek medical attention immediately, as these could indicate a tick-borne illness.
For more information about symptoms and tick-related diseases, consult a medical professional or visit trusted sources like the Centers for Disease Control.
American dog tick prevention and control
Ticks can be difficult to control, which is why prevention and professional services are essential. To reduce the risk of encountering ticks, avoid heavily infested areas when possible. If you must be in tick-prone environments, follow these tips to stay safe and always remember to check yourself for ticks after spending time outdoors:
Wear long-sleeved shirts and long pants. Light-colored clothing is best since it makes ticks easier to spot.
Secure the bottom of your pants inside your socks or tie them tightly around your ankles.
Wear a hat and tuck long hair underneath to limit areas where ticks can latch on.
Apply tick repellent to your clothing, focusing on the lower body and arms.
Inspect your body thoroughly after leaving infested areas and ask someone to help check your back and scalp.
Wash potentially infested clothing immediately in warm water and detergent. Do not mix clothing with other laundry or leave it on the floor.
Protect pets by keeping them out of tick-heavy areas and using tick treatments recommended by veterinarians. Inspect pets carefully after walks in wooded or grassy areas, as dogs can contract many American dog tick diseases.
If ticks are already in your yard, professional treatments can help manage infestations. Terminix offers effective tick control services to help prevent and target problem areas to reduce the risk of ticks spreading American dog tick diseases to your family and pets.