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What does a tick look like?
Ticks have eight legs, no wings, and never jump. That rules out most look-alikes.
Quick test
- Count the legs. Eight on an adult tick. Six on an insect.
- Does it jump? Fleas jump. Ticks crawl slowly.
- Is it attached? A tick embeds its mouthparts and does not brush off.
- Any wings? Ticks have none.
Commonly mistaken for a tick
| Look-alike | How to tell |
|---|---|
| Flea | Flat side-to-side, jumps, six legs |
| Skin tag or mole | Same colour as the skin, no legs, unchanged day to day |
| Scab | Dry and flaky, sits on the surface |
| Small spider | Eight legs, but a clear waist, and moves quickly |
| Dirt or a seed | Brushes off; a tick does not |
If it does not brush off and it has eight legs, treat it as a tick and remove it.
The basic shape
A tick’s body is a single flattened oval, and there is no separate head, thorax and abdomen the way an insect has. Everything sits in one shield-shaped case, with the mouthparts poking out at the front. Look closely and you can usually make out two parts:
- The capitulum: the small, dark, beak-like structure at the front. This is what stays in the skin, and it is often the only part visible once the tick has attached.
- The idiosoma: the larger rounded body behind it, where the legs attach. This is the part that swells as the tick feeds.
Colour ranges from reddish-brown to almost black in an unfed tick, sometimes with a paler shield (called a scutum) near the front of the back. Some species have mottled or patterned markings on that shield, which can help with identification but is easy to miss with the naked eye.
How feeding changes the shape
An unfed tick is flat, roughly the size and shape of a sesame seed, and easy to overlook. As it feeds, the idiosoma stretches and swells, sometimes into a smooth grey or blue-grey sac many times its original size. At that point the legs look disproportionately small compared with the body, and the colour has usually shifted from brown to a dull grey.
This matters for identification because a swollen tick looks very different from a flat one, and people sometimes do not recognise an engorged tick as a tick at all: it can be mistaken for a small blood blister or a skin growth. For more on the size progression by life stage, see how big are ticks.
Larva, nymph and adult look different
A tick’s appearance also changes as it grows. Larvae have six legs rather than eight and are barely visible without magnification. Nymphs have all eight legs but are much smaller and paler than adults, which is part of why they are so easy to miss. Adults are the largest unfed stage and the ones most people picture when they think of a tick. Females are usually larger than males and swell much more when feeding, since they need the blood meal to produce eggs.
United States & Canada
The species people most often photograph are the blacklegged (deer) tick, the American dog tick, and the lone star tick. The lone star tick has a single pale spot on the female's back, which is a useful visual cue the others do not share.
Australia
The paralysis tick is the species of most concern, found along the eastern coastal strip. It has a similar oval, flattened shape to ticks elsewhere, and an engorged paralysis tick can look strikingly pale and grey.
UK & Europe
The castor bean tick is the most commonly encountered species, with a dark brown to black unfed body and a noticeably pale, greyish shield in some individuals.
Getting a second opinion
Photos rarely settle the question on their own, especially with a small or partially embedded tick. If you have a clear photo and want a species-level guess, the tick identifier compares it against reference images. If you are checking skin in real time rather than working from a photo, Live Scan highlights small dark shapes against skin using contrast, which can help you spot something worth a closer look. It is a visual aid, not a diagnosis, and it does not confirm what the shape actually is.