Animal and human bites occur for a number of reasons, depending on the animal or person involved and the circumstances.

An animal bite that becomes infected should be seen by a healthcare professional. Humans bites should always be assessed by a healthcare professional. 

Dog bites

Many dog bites are unprovoked. A family dog or a dog that belongs to a friend or neighbour is usually responsible.

Dogs are territorial creatures and sometimes perceive innocent actions as an invasion of their territory. They may interpret certain actions as hostile acts, prompting them to bite.

Actions that may cause a dog to bite include:

• disturbing it when it's sleeping/eating/caring for its puppies
• running, screaming or shouting in its presence
• being petted by someone they don't know (always let a dog smell your hand before stroking it)

Some dogs, particularly young ones, can get over-excited when playing, and may accidentally give a friendly nip. Dogs that are sick or in pain can also react unpredictably.

The dogs that are most likely to cause more severe bites are the larger and stronger breeds. These include:

• German shepherds (alsatians)
• pit bulls (breeding, selling or exchanging pit bulls is banned in England under the Dangerous Dogs Act 1991)
• rottweilers
• dobermans
• chows

However, any breed of dog should be regarded as being potentially dangerous, and smaller dogs – such as Jack Russells, dachshunds and chihuahuas – are often more aggressive than larger dogs.

Cat bites

It's estimated that the majority of cat bites come from stray, female cats. All cats are predators and they can react unpredictably. This is particularly true of undomesticated cats (those that aren't used to living in a house with people).

Around one in five cat bites are from a person’s own cat. A pet cat may bite if they:

• mistake a sudden action as an aggressive act
• get excited when playing – they may jump at and bite a moving object, such as your hand
• can't attack their intended target, such as another cat – they may lash out at the nearest target

Sometimes, for reasons that are unclear, an apparently contented cat can suddenly bite their owner after being petted for a few minutes.

Human bites

Most human bites occur when one person punches another person in the teeth (these are know as fight-bites). Young men who have been drinking heavily are usually those involved.

Intentional bites are common in very young children and in people with severe learning difficulties, as these groups are often unaware that such behaviour is socially unacceptable.

Accidental bites can happen during contact sports, such as rugby and football, when a person accidentally knocks another person’s teeth.

Accidental bites can also occur during vigorous sexual activity, particularly oral sex. Although you may feel embarrassed, always seek medical treatment for this type of accidental bite, because there's a high risk of it becoming infected.

Other causes of human bites include:

• domestic violence or sexual assault 
• accidentally biting your tongue during a seizure (fit)
• self-inflicted biting, which can sometimes occur in people who are emotionally disturbed or mentally disabled

Other types of animal bites

Bites from pets such as hamsters, rabbits and guinea pigs tend to be less common and less serious than bites from dogs and cats. However, they can sometimes occur when children stick their fingers through the bars of the pet’s cage.

Bites from animals other than pets are less common in England, but they are more of a concern for certain occupations. For example, people who work with pigs are sometimes bitten, and monkeys and apes can be a problem for zoo and laboratory workers.

Read more about how to avoid bites.