Fleas are mean, lean, biting machines — creatures that are perfectly designed by nature to pester your pet. Like a shark in the water or a wolf in the woods, fleas are ideally equipped to do what they do — which is to be out for blood! A close-up look at these tiny parasites shows just how well adapted they are for this job and why those adaptations can make them so hard to get rid of once an infestation gets underway.
First, fleas have a very hard exoskeleton. Their bodies are covered by a tile-like shield of tough plates called “sclerites.” This makes squishing them — if you are lucky enough to even catch one at all — almost impossible. This exoskeleton is waterproof and shock resistant, and it helps fleas to resist some of the sprays and chemicals that people use to try and kill them.
Second, growing from these plates are little spines that bend backward. These spines lie flat against the flea’s thin, narrow body and don’t get in the way as the flea scurries through your pet’s fur in search of food. However, if anything (like fingers or a self-grooming pet) tries to pull a flea off through that hair coat, these spines will stick to your pet’s fur like Velcro, making them difficult to remove.
Third, pound for pound — or should we say, milligram for milligram — fleas are one of the best jumpers in the natural world. A flea can jump 150 times its own length vertically or horizontally — almost seven inches high. That’s the equivalent of a person being able to jump a thousand feet in the air. When they jump, fleas also accelerate through the air at the amazing rate of 140 g’s. That’s astounding if you consider that fighter pilots need special equipment and training to avoid passing out at forces of 9 g’s during turns in a fighter jet. Somehow, though, the tiny flea not only survives these superhero-size feats — it thrives because of them.
There are a couple of interesting reasons why fleas can do what they do. First, fleas have very long rear legs with huge thigh muscles and multiple joints. When they get ready to jump, they fold those long legs up and crouch like an Olympic track star on a starting block. Second, several of their joints include small, springy pads of a special material called resilin. This material stores energy and helps catapult fleas into the air as they jump, sort of like the way a rubber band adds momentum to a slingshot. This makes it easy for adult fleas to find and quickly jump onto your pet as it walks by. And then there’s a final adaptation that helps them to hang onto anything they reach once they get there. Fleas have tiny eyes and don’t really have very good aim when they jump. Many times, they simply tumble and somersault through the air as they fly toward their target. When they land, though, they have small, outward facing claws on the bottoms of their legs. These claws help them to grab and hold onto anything they touch when they land.
Fight Perfection With Prevention!
For all of these reasons, you are facing an intimidating if tiny opponent once a flea infestation is underway in your household. In addition to all these perfected physical adaptations, fleas also have amazing life cycles that allow immature stages to lie dormant until conditions are favorable for them to emerge and find food. The best way to control fleas, therefore, is to simply prevent them in the first place. Environmental sprays and topical sprays can help reduce an established problem, but the most efficient and least messy way to avoid fleas is to use one of the many topical or oral monthly flea prevention products that are available through veterinary hospitals. These products are effective and easy to use. If you do not have a prevention and control program for fleas in place, be sure to ask for recommendations at your next veterinary visit.
Don't forget about heartworm prevention while tackling the issue of pet parasites. The American Heartworm Society and the Companion Animal Parasite Council recommend that all pets receive year-round heartworm protection so that pets are protected every month. It is critical that doses not be skipped or intervals between doses be extended because this results in an unprotected time during which animals may be exposed to heartworm larvae. Pets should also have annual heartworm testing by a veterinarian prior to prescribing a heartworm medication.
Revised and updated Dec. 18, 2012.
This article originally appeared in PetsMatter July/August 09 - Volume 4 Issue 4, published by the American Animal Hospital Association. Copyright © 2009 AAHA. Find out more.