Tick Ecology
Ticks are small arachnids (related to spiders) that feed on the blood of mammals, birds, and sometimes reptiles. They are not insects. In the UK, ticks are the most important vectors of disease affecting both humans and animals.
UK Tick Species
Four tick species are commonly encountered in the UK:
- Ixodes ricinus — the most common UK tick, found across grassland, woodland, and moorland. Bites humans, pets, livestock, and wildlife. Can transmit Lyme disease and other pathogens.
- Dermacentor reticulatus — the ornate cow tick, found mainly in coastal areas of Wales, Devon, and Essex. A concern for dogs as it can transmit canine babesiosis.
- Ixodes hexagonus — the hedgehog tick, often found on pets that have contact with hedgehog nests or burrows.
- Haemaphysalis punctata — found mainly in coastal grasslands in southern England.
Life Cycle
Ticks go through four life stages: egg → larva → nymph → adult. A nymph is the juvenile stage between larva and adult, not a baby adult. After hatching, ticks need a blood meal at each stage to develop to the next. This process typically takes 2–3 years to complete in the UK.
- Larvae — tiny (less than 1 mm), with 6 legs. Usually feed on small mammals and birds.
- Nymphs — about 1–2 mm, with 8 legs. Responsible for most human disease-transmitting bites because they are small and hard to notice.
- Adults — 3–4 mm unfed, up to 11 mm when engorged. Females need a large blood meal before laying eggs.
Example tick life cycle illustration. Timing and host use can vary between species. Attribution: CDC tick life cycle guidance.
Where Are Ticks Found?
Ticks don’t fly or jump. They wait on vegetation (grass, bracken, leaf litter) with their front legs outstretched — a behaviour called questing, meaning they are waiting to grab onto a passing animal or person. When an animal or person brushes past, they grab on.
Common tick habitats in the UK include:
- Woodland edges and clearings
- Long grass and bracken
- Moorland and heathland
- Parks and gardens (especially near deer or hedgehog activity)
When Are Ticks Active?
Ticks are most active from March to October, with peaks in spring and early autumn. They become active when temperatures rise above around 4°C and humidity is high. Mild winters can extend the season, and climate change is contributing to ticks being found at higher altitudes and more northerly locations than previously recorded.
Why Do Ticks Matter?
Ticks can transmit bacteria, viruses, and parasites while feeding. In the UK, the most significant tick-borne disease is Lyme disease, caused by Borrelia bacteria. Other UK tick-borne infections include anaplasmosis, babesiosis, and tick-borne encephalitis (TBE). Not every tick carries disease, but prompt removal reduces risk — see our tick removal guide.