How and Where Dogs Get Fleas

Sometimes it seems that fleas just come out of nowhere.  You buy a puppy, it’s flea-free and everything is fine.  Then it starts to itch.  It scratches.  A lot.  How and where did your dog get fleas?


Dogs Playing on Beach

Dogs pick up fleas from each other and the environment; sand can harbour flea eggs. Photo Credit: Federico Stevanin/

How Dogs Get Fleas

Fleas are highly adapted insects.  They are built to seek out your pet and feed on him.  Fleas have a four stage life cycle and this enables them to choose the best moment to strike at your dog.  Get to know the life cycle of a flea; it is essential knowledge in your fight to get rid of fleas.

The flea in its pupate state lies in wait for the approach of an animal.  The sound, vibration and heat of an approaching dog or cat stimulates it to emerge from its cocoon.  Once out, it needs to find food:  blood.  Your animal will act as its host and food source.

Your dog may also pick up an already hatched adult flea.  Adult fleas usually live for a couple of months and once fed can live without food for weeks.  However, if they find your dog, they will readily hop on to feed again.

Where Dogs Get Fleas

Generally, animals pick up fleas outside.  Flea eggs don’t live on an animal, they are designed to drop off.  Once they have fallen they will hatch in a few days and the larvae will seek out a dark place to feed.  Therefore, there are fleas waiting to emerge from pupae in grass, weeds, sand and crevices all around the environment.  Anywhere dogs or cats go, there will be fleas, in one of the stages of their life cycle, waiting for a host.

Your pet may also pick up fleas from other animals.  If your dog likes to sniff other dogs and play rough with them, the contact is enough for an adult flea to transfer from one dog to another.  Fleas can jump several inches, so it’s not hard to see that they can move between animals.

If your dog is outside, it could catch fleas. Photo Credit:

In some cases your dog may pick up fleas a building.  It may be the home of another pet owner, whose own animal has shed flea eggs into the house.  In some cases you can visit a building that has no pets and still your dog can pick up fleas.  How?  The flea pupae can lie dormant for up to two years.  The stimulus of an animal, ie the vibration, heat, carbon dioxide (in breath), causes the flea to emerge to feed, as described above.

How Do You Avoid Fleas?

You can’t.  Fleas are a part of the environment, they are all around.  Unless you keep your dog inside constantly (that is not an option!) it will be exposed to fleas at some point.  The good news is that there is usually some respite during cooler weather; the fleas are not active in the cold.

The best course of action is to prevent an infestation.  One flea can quickly escalate.  If you let it slide, even for a few weeks, you will soon be facing an uphill struggle, which will be expensive and time consuming.


  • Your animal can catch fleas easily from other animals and the environment
  • Fleas are highly adapted to living outdoors and lying in wait for your pet
  • You won’t be able to avoid fleas
  • You will be able to control fleas through vigilance and regular treatment