Tick species identification

Blacklegged (deer) tick

What to look for

Small, reddish-brown to black, with no ornate white markings. Unfed nymphs can be about the size of a poppy seed.

Blacklegged (deer) tick photos by life stage

Compare more than color alone. Sex, life stage, feeding, angle, and lighting can change what the markings look like.

Adult female blacklegged deer tick with a black shield and orange-red body on a leaf — Adult female. Black legs and shield over an orange-red body. Photo: Scott Bauer, USDA ARS, public domain.

Adult blacklegged tick and a much smaller nymph on a fingertip — Adult (left) and nymph (right) on a fingertip. Nymphs are about the size of a poppy seed. Photo: CDC, public domain.

Engorged adult female blacklegged deer tick, swollen and gray-brown — Engorged female. Feeding swells the body to a gray-brown oval; the small dark shield stays near the head. Photo: NIAID, CC BY 2.0.

Blacklegged tick adult female, adult male, nymph, and larva beside a quarter-inch scale and a dime — Life stages to scale: adult female, adult male, nymph, and larva next to a dime. Photo: CDC, public domain.

Known disease associations

— Lyme disease
— Anaplasmosis
— Babesiosis
— Borrelia miyamotoi disease
— Powassan virus disease

Finding this species does not mean the tick carried a pathogen or that transmission occurred.

Photos need context

Feeding, life stage, image angle, and damage can change how a tick looks. A useful identification weighs several visible traits together and states uncertainty when the photo does not show enough detail.

Not sure whether yours is a deer tick or a dog/wood tick? See the deer tick vs. dog tick comparison with photos.

References: CDC tick information.