The first thing to know about fleas is that they're hardy little parasites and you don't have to have a dog or cat to suffer from them. Active flea season depends on where you live; some places have to contend with them year round while others get to take a break during cold winter months. Fleas can survive in a dormant state under the right conditions in cold weather, meaning if they aren't actively bothering you or your dog during the winter they may still be present, waiting for the right opportunity.
Flea Life Cycle
The flea has four parts to his life cycle, which starts when an adult flea lays eggs on a host animal:
Egg: When the host animal, such as your dog, moves around, he deposits flea eggs anywhere -- the grass, in bedding, upholstery, carpeting, cracks in the floor.
Larva: Eggs hatch and develop where they landed, feeding on whatever organic material they find, such as skin scales and adult flea feces.
Pupa: After molting twice, the larvae grow and form a cocoon, hatching when the environmental conditions are right and a host is available.
Adult: Vibrations, heat and exhaled carbon dioxide signal it's time to emerge from the cocoon so the adult emerges and jumps onto an available host to begin the cycle anew.
The life cycle can occur in two weeks or take much longer, depending on the environment.
Patient, Hardy Fleas
Fleas love temperatures between 65 and 80 degrees Fahrenheit, with a humidity level between 75 and 85 percent, however they'll make do with what they're given and are patient when they need to be. Pupae can remain dormant for up to 30 weeks and adults can emerge within two weeks or delay as long as 50 weeks. As well, they can overwinter if it doesn't get too cold; the cat flea can survive 10 days at temperatures around 37.4 degrees Fahrenheit or for five days at 33.8 degrees. While freezing temperatures will kill exposed fleas, those that are tucked away in nests, your home or even on your pet in a dormant state in the cold of winter will wait until conditions are right to emerge. The bottom line: Fleas are a year round proposition, in one form or another.
Even if your dog or cat spends minimal or no time outside, you still should practice flea prevention because you can be a flea's entry into your home and onto your pet. If home is in a warm weather climate, you should consider year round flea control; for cooler climates that experience freezing temperatures, initiate flea prevention in the spring, before the pupae emerge. Flea preventives vary widely according to what stage of development they address. Some kill adult fleas only while others leave the adults alone but prevent egg hatching to break the life cycle -- effective only if the animal never comes in contact with another flea. Discuss the best option for your pet with your vet.