What do fleas look like?
Adult fleas
- 1–3 mm long
- Dark reddish-brown in colour, appearing almost black
- Flat-bodied and wingless, with long, powerful hind legs built for jumping
- Visible to the naked eye, though they move extremely fast
Flea larvae
- Tiny, pale, and thread-like — resembling small maggots
- Up to 5 mm long when fully developed
- Found deep in carpet fibres, pet bedding, and floor cracks — rarely seen in the open
The cat flea is by far the most common species found in UK homes. Bird fleas, sometimes present in properties with nesting birds in the roof space, tend to appear slightly darker and larger.
On humans, flea bites typically appear as:
- Small, raised red spots, often with a darker red dot in the centre
- Clusters or a line of two to three bites
- Most commonly found around the ankles, lower legs, and waist, or where clothing fits closely against the skin
- Intensely itchy, often more so than mosquito bites
On pets, signs of flea bites include:
- Persistent scratching, biting, or chewing at the skin
- Hair loss, particularly around the base of the tail
- Red, irritated patches or scabs
- Restlessness and agitation
Can fleas live on humans?
This is one of the most common questions we receive. The answer is: not permanently.
The fleas most commonly found in UK homes are cat fleas, which strongly prefer furred animals. They will bite humans readily but cannot complete their life cycle on a human host, as we lack the fur they need to lay and keep their eggs.
That said, if a pet leaves the home, fleas will turn to human occupants as an alternative food source — which is why people often notice increased biting after a pet has been away or rehomed.