What reasons do fleas like cats and dogs?

Question

What is so great about our pets that the fleas love?

Answer 1

Fleas love to suck the blood out of all animals including humans.

Answer 2

Fleas are animal specific.  There are cat fleas, dog fleas, human fleas etc.  They feed specifically on the blood of those animals and breed in the hairy parts of the animals.

Interestingly the worst problems humans usually have is after a pet with fleas has died or left.  The fleas no longer have anyone to eat so they start biting whatever they can find.  This is why sometimes people moving into new apartments can find themselves with a flea problem even though they do not own any pets.

Without their natural host the fleas cannot survive, but they sure can make life miserable for a while.

Answer 3

because they are very hairy