How many fleas can live on a cat or dog?


Infested cats and dogs typically have less than 20 fleas living on them. It’s believed that pets can support a maximum of 200 to 300 fleas. However, one study showed that fleas won’t abandon their host, even when the corporeal population exceeds 300.


Average Number of Fleas on Pets

When infested with fleas, the average dog or cat will have less than 20 fleas living on them. The flea population on an animal is referred to as the flea burden.

Maximum Number of Fleas on Pets

It’s theorized that dogs and cats are can support a maximum of 200 to 300 fleas. And, once this population baseline is reached, the fleas begin jumping off the animal. However, one study refuted this claim, showing that fleas won’t abandon their host even when populations exceeds 300 fleas. Regardless, a burden of over 200 fleas is rare. 150 fleas is considered high.

Younger Animals Have more Fleas

There’s a direct relationship between host age and flea burden. More fleas are found on young animals. Juvenile cats, for example, aren’t as seasoned at grooming as older cats. Additionally, mature cats may have better immune systems, thicker skin, and differences in their blood capillaries.

Animal Surveys

Flea Burden on Cats

In one study, 164 of 200 surveyed stray cats had fleas. An average of 20 fleas were found on each cat. The most heavily infested cat had 161 fleas living on it.

In southern California, 323 of 701 surveyed domestic cats were flea-infested. A total of 6729 fleas were recovered, and 85% were female. There were two main distributions, cats with less than 7 fleas, and cats with more than 50 fleas Fig 1. At a maximum, one kitten had a burden of 440 fleas.

Fig 1 Number of cats (y-axis) with varying populations of fleas (x-axis).

A New Zealand survey recovered 1578 fleas from 81 stray cats. The average flea burden was 19.48 fleas. At a maximum, one cat had 108 fleas.

A survey in Spain counted fleas on cats which were bought into veterinary clients. 1938 fleas were recovered from 217 cats. On average, an individual cat had 9 fleas living on it. However, in one extreme case, a cat had a burden of 245 fleas.

A survey in southern California found 70% of the infested cats had less than 7 fleas.

In Georgia, an average of 28.2 fleas were found per feral cat.

In Australia, the average flea burden on cats was 7.7 fleas.

In 1915, 139 stray cats were surveyed, and 114 had fleas. The average cat had 4.24 fleas. None had above 30.

In Albania, the number of fleas found on cats was between 1 and 9.

In Wisconsin, of 16 infested cats, the average flea burden was 8.15 fleas. At a maximum, one cat had 164 fleas.

A Hungarian survey observed 1000 cats brought into veterinary clients. 229 cats were infested with fleas. On average, less than 5 fleas were found on the cats. The largest burden was 118 fleas.

Flea Burden on Dogs

Veterinary clinics in Italy found fleas on 246 of 1376 surveyed dogs. A total of 960 fleas were discovered. 79 dogs had 1-5 fleas living on them, 89 dogs had 6-20 fleas, and 78 dogs had over 20 fleas.

In New Zealand, a survey was done on stray dogs captured by authorities. 357 fleas were recovered from 48 dogs. The mean burden was 7.44 fleas. A max of 54 fleas was found on one dog.

In Australia, the average number of fleas per dog was 10.2.

In one extreme case, a single dog in Spain had 967 fleas living on it.

In Albania, the flea burden on dogs ranged from 1 to 80.

In Wisconsin, 9 infested dogs had an average of 4.5 fleas per dog.

A Hungarian survey tested 2267 dogs in veterinary clients. 319 dogs were flea-infested. The average dog had less than 5 fleas. At a maximum, an individual dog had 95 fleas.


Have an unrelated question?

ask a question


  • Terralyn November 2, 2016, 3:39 pm

    My dog is only 20 lbs but he has a lot of fleas! How long do we have to get them off of him before it starts to do damage to his body???

    • Adam Retzer November 2, 2016, 4:26 pm

      It’s best to get them off as soon as possible, as they are continually biting. The bites cause irritation. If your dog is allergic (flea allergy dermatitis), the irritation can be severe. This can lead to excessive grooming, resulting in hair loss and skin infections. There are also multiple diseases that fleas can spread to dogs.

      Each female flea lays around 25 eggs a day. They fall into the environment (carpets) and develop there. The longer the dog goes untreated, the more eggs will accumulate in the environment. If the problem is neglected too long, the infestation can get severe and will be much harder to control.