Pet Factsheets

Adder bites in cats

The European adder (Vipera berus berus) is the only venomous snake native to the UK. It is also found across northern Europe and Asia, but not in Ireland.

Adders vary in colour; males can be grey to white and the females are shades of brown or copper. The adder can be recognised by its black/brown zig-zag down its back and a V-shaped marking on the head. Adults grow up to 60 cm in length.

The European adder is not an aggressive snake and only bites when provoked. Bites rarely occur during the winter when the snake is in hibernation but are frequent during the summer months. Adders are found in heaths, sand dunes, moorlands and woodland margins in summer.

What are the potential signs of adder bite in cats?

Bites are most common in dogs, typically on the head, neck and legs. It is uncommon for a cat to be bitten. The snake itself is often not seen. 

The effects of adder bite are usually seen soon after the bite (within 2 hours) and include:

  • Local swelling at the bite site. If on the muzzle, this may affect the cat's ability to drink/eat or may affect breathing
  • Puncture wounds may be visible
  • Lethargy
  • Distress
  • Vomiting and diarrhoea, salivation
  • Lameness (if bitten on the leg)
  • Bruising
  • Collapse and abnormal bleeding
  • There may also be effects on the heart, kidneys, liver and blood

Local swelling occurs within a few hours and can get worse over the following 24 hours or more. Adder bites can be life-threatening but the majority (more than 95%) recover. Recovery can take several days.

How do I reduce the risk of adder bite in my cat?

Keep your cat away from high risk areas especially when adders are most active (March to October).

What should I do if I think my cat has been bitten by an adder?

Do not attempt to handle or harm the snake. The European adder is a protected species and it is illegal to injure or kill them.

Leave the bite alone. Do not attempt to suck out the venom, cut the wound open or apply a tourniquet, as these interventions are ineffective and may introduce infection, aggravate bleeding and restrict circulation of blood.

Ideally you should try and keep your pet quiet. Carry them home, back to your vehicle or to the veterinary surgery. This can help reduce the spread of venom around the body.

All pets bitten by an adder should be taken to a veterinary surgery. 

What information will help my vet?

On arrival at the veterinary surgery someone will assess your pet immediately and make sure that its condition is stable before any other treatments are instigated. Your vet will want to know:

  • What happened (where the incident occurred, how your pet behaved). Remember you may not have seen the snake bite your pet or even the snake itself
  • If you have seen the snake, try and describe it to your veterinary surgeon
  • How long ago the incident happened
  • If your pet is showing any signs of being unwell
  • If your pet is receiving any medication or has any pre-existing medical conditions