When you put a flea collar on your dog or cat, it releases chemicals that spread along your pet’s body through the oils on his fur and skin, according to MedicAnimal.com. These chemicals will linger, killing any fleas that try to settle on your canine or feline companion. Flea collars can protect your pet for up to seven months, because they’re designed to slowly release the bug-killing chemicals over time.
There are different collars for dogs and puppies, as younger animals will need less to provide the same level of protection. If you have a puppy younger than 6 months, you can get him the Hartz® UltraGuard Plus® Flea & Tick Collar for Puppies, which will kill fleas and their eggs for months.
There are similar products available for cats and kittens. Hartz flea collars with “plus” in the name are effective at stopping the flea lifecycle at any point. Other products, such as the Hartz® UltraGuard® Flea & Tick Collar for Cats and Kittens, target adult insects.