Bug Identifier

Ticks, Mites & Other Arachnids

American Dog Tick

Dermacentor variabilis

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Body length in millimeters. Shaded bar shows the typical adult range.
Scientific nameDermacentor variabilis
GroupTicks, Mites & Other Arachnids
Size3–5 mm (up to about 0.20 in)
Colors Brown, White and Gray
Legs8 legs
WingsNo (as usually seen)
Where foundLawn or grass, Woods or trails and On pets
Most activeSpring and Summer
BitesYes
StingsNo
Risk levelHealth risk

How to identify it

The American dog tick is a small member of the ticks, mites & other arachnids group. Eight legs as adults, no antennae and no wings. Check for these three features:

  1. Brown body with silvery-white mottling on the shield
  2. Larger than a blacklegged tick
  3. Engorged females turn slate gray and swell up to 15 mm

About this bug

A brown tick with ornate white-gray markings on its shield, common along trails, roadsides and grassy fields. It readily feeds on dogs and people.

You'll usually find American dog ticks in lawns and grass, in woods and along trails and on pets. They are most active in spring and summer.

Is it dangerous?

American dog ticks can transmit Rocky Mountain spotted fever and tularemia.

Our rating: Health risk, meaning it can cause medically significant bites, stings or disease.

Call 911 right away if someone has trouble breathing, swelling of the face or throat, dizziness or a racing heartbeat after a bite or sting.

When you'll see American dog ticks

American Dog Ticks are most active in spring and summer. In spring, overwintering adults become active and many species lay their first eggs. Summer heat speeds up development, so populations can grow quickly.

Typical places to check: lawn or grass, woods or trails and on pets.

About ticks, mites & other arachnids

The American dog tick is one of the ticks, mites & other arachnids. This group includes ticks, mites, scorpions and harvestmen. Like spiders, adults have eight legs and no antennae, though larval ticks and chiggers have only six. Ticks and some mites feed on blood or skin, while scorpions hunt insects and harvestmen scavenge.

Ticks move through larva, nymph and adult stages, and each stage needs a blood meal. Nymphs are tiny and active in late spring and summer, which is when many tick-borne infections happen.

What to do about it

  1. Treat dogs with a veterinarian-recommended tick preventive
  2. Stay in the center of trails and avoid tall grass
  3. Check pets and people daily during spring and summer

Read the full guide: how to get rid of American dog ticks.

Bugs that look similar

Blacklegged TickIxodes scapularis1–5 mmHealth risk

Color: American Dog Ticks are brown, white and gray; blacklegged ticks are black, red and brown.

Lone Star TickAmblyomma americanum3–6 mmHealth risk

Color: American Dog Ticks are brown, white and gray; lone star ticks are brown, red and white.

Frequently asked questions

What does an American dog tick look like?

Brown body with silvery-white mottling on the shield. Adults measure 3–5 mm (up to about 0.20 in).

Does the American dog tick bite or sting?

It can bite. It does not sting. American dog ticks can transmit Rocky Mountain spotted fever and tularemia.

Where do American dog ticks live?

American Dog Ticks live in lawns and grass, in woods and along trails and on pets.

When are American dog ticks most active?

Mostly in spring and summer.