Written by Phillip George · Last updated: July 24, 2026
Blacklegged (deer) tick
Ixodes scapularis
Solid reddish-brown body with darker legs; no pattern. Unfed adult ~3 mm (sesame-seed); nymphs are poppy-seed tiny.
Where: Northeast, Midwest, upper Southeast US and eastern Canada.
Can carry: Lyme disease, anaplasmosis, babesiosis, Powassan virus.
CDC species & photosWestern blacklegged tick
Ixodes pacificus
Solid dark body, similar to its eastern cousin. Small; nymphs poppy-seed tiny.
Where: Pacific coast US and southern British Columbia.
Can carry: Lyme disease (lower infection rates than the East), anaplasmosis.
CDC species & photosAmerican dog tick
Dermacentor variabilis
Ornate brown body with whitish/silver marbling on the shield. Larger (~5 mm unfed). Often called a "wood tick."
Where: Widespread east of the Rockies, the Pacific coast, and into the Canadian Prairies.
Can carry: Rocky Mountain spotted fever, tularemia; can cause tick paralysis. Not a Lyme carrier.
CDC species & photosLone star tick
Amblyomma americanum
Round, reddish-brown; the female has a single white/silver dot in the centre of her back. Aggressive biter. (Males have faint pale streaks near the edge.)
Where: Southeast and eastern US, spreading north; common on Long Island and in the mid-Atlantic.
Can carry: Ehrlichiosis, STARI, tularemia; its bite is linked to alpha-gal (red-meat) allergy.
CDC species & photosRocky Mountain wood tick
Dermacentor andersoni
Ornate brown body with whitish marbling, very similar to the American dog tick. Larger (~5 mm unfed).
Where: Rocky Mountain states and interior British Columbia/Alberta, in shrubby and grassland areas.
Can carry: Rocky Mountain spotted fever, Colorado tick fever, tularemia; can cause tick paralysis.
CDC species & photosBrown dog tick
Rhipicephalus sanguineus
Solid, uniform reddish-brown with an elongated body. The only common tick that readily lives and breeds indoors (homes, kennels).
Where: Across the US, most impactful in the warm Southwest; worldwide.
Can carry: Rocky Mountain spotted fever (notably in the Southwest); a major concern for dogs.
CDC species & photosGulf Coast tick
Amblyomma maculatum
Ornate brown body with silvery markings; resembles the dog tick but favours coastal prairies.
Where: Gulf Coast and southeastern US, expanding inland.
Can carry: Rickettsia parkeri spotted fever (a milder spotted-fever illness).
CDC species & photosAsian longhorned tick
Haemaphysalis longicornis
Solid, small, plain reddish-brown with no clear markings. Invasive; can appear in huge numbers on a single animal.
Where: Eastern US since 2017 (first found in New Jersey), spreading.
Can carry: Mainly a livestock and pet threat in North America; its role in human disease here is still being studied.
CDC species & photosHow to be sure — and what to do next
This narrows the field, but the safest confirmation is an expert looking at a clear photo. These free or low-cost services identify ticks and, in some cases, test them for pathogens:
- Canada: eTick.ca — upload a photo, get an expert reply (usually within 24 hours).
- Pennsylvania: PA Tick Research Lab — free tick testing for PA residents.
- US (mail-in): TickReport (UMass Amherst) — identification and pathogen testing.
- Your area: many state and provincial health departments identify ticks — see our USA and Canada guides.
Remove it safely
Fine-tipped tweezers, steady upward pull, and mistakes to avoid.
Tick removal guideQuick tips
- Photograph the tick's back in good light before it feeds.
- A fed tick swells and darkens — markings can disappear.
- Only Ixodes (blacklegged) ticks spread Lyme in North America.
- Save the tick in a sealed bag in case testing is offered.