What’s the Difference Between Fleas and Ticks?

What do these two tiny pests have in common and how are they different? Two bug experts help break it down.

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Side by side comparison of a lose up of a flea and a tickGetty Images (2)

Having fleas and ticks in and around your home can be worrisome — especially for those of us with pets.

Though fleas (photo on left, above) and ticks (photo on right) both feed on the blood of mammals, transmit diseases and sometimes cause painful allergic reactions, they’re actually very different.

Fleas are tiny blood-sucking insects that infect wild animals (think raccoons and rodents) as well as domestic ones (mainly dogs and cats). They reproduce quickly and attach to one host throughout their lifetime.

“Fleas are fantastic jumpers,” says Katelyn A. Kesheimer, Ph.D., an assistant professor and extension specialist at the Alabama Cooperative Extension System, Auburn University. Their large back legs let them jump more than six inches. For a small insect, that’s a huge leap!

Ticks are slightly larger than fleas, but still small and hard to spot. Members of the arachnid family (i.e., spiders and mites), they’re eight-legged hitchhikers who latch onto their prey, burying their heads into the skin after biting. Unlike fleas, ticks are nomads who move from one host to another at a whim.

Should you find one of these blood-sucking critters on your pet, it’s important to recognize the specific signs and symptoms of each so you’ll know what to do.

What Do Fleas and Ticks Look Like?

Though both are relatively small, fleas and ticks have noticeable physical differences. Here’s how to tell which is which.

What fleas look like

Fleas are usually dark reddish-brown to black with flat, wingless bodies and needle-like mouthparts. When they bite, they penetrate the skin, causing itching and swelling. Adult fleas measure about 1/8-in. long with three pairs of legs. Here are a few ways to find out if your pet has fleas.

Jim Fredericks, Ph.D., an entomology and wildlife ecology specialist and senior vice president of public affairs for the National Pest Management Association, says fleas can be hard to spot with the naked eye because they move so fast along the animal’s body. “Flea combs and wetting an animal’s hair can help you grasp them for a visual inspection,” he said.

What ticks look like

Nearly 100 tick species live in the United States, and they come in all kinds of colors (brown, black, gray, red, yellow, etc.). The most common types in North America include blacklegged/deer, American dog, brown dog, lone star and Rocky Mountain wood ticks.

Ticks can range from 1/8-in. (the size of a sesame seed) to as much as 1/2-inch. They’re flat top to bottom but grow round when engorged with blood. Nymph and adult ticks have four pairs of legs but only three pairs in the larvae stage.

Did you know? A recent survey found 63% of Americans have seen or removed a tick from themselves, someone else or a pet.

Where Do Fleas and Ticks Live?

Fleas

“Almost all indoor flea infestations are because of a pet (or other animal),” says Kesheimer. Fleas may live in the yard for a while. But as soon as they find a ride into the house, they’ll abandon the outdoor life for the warmth of the indoors.

Fleas are generally content to spend their entire lives on the same hairy dog or furry cat, happily feeding and reproducing. They lay their eggs, which eventually fall off the animal and hatch into tiny worm-like larvae, infesting carpets and furniture. After emerging as adult fleas, they’ll jump back onto their host, and the cycle continues.

Did you know? Fleas can produce as many as 400 to 500 offspring in their lifetime.

Ticks

Ticks thrive in warm, humid climates and prefer to hide in tall grass, scrubs and wooded areas. They’re not only relegated to forested or rural areas; they can also be found in urban centers or coastal locations.

“Ticks usually contact a host by crawling up on the tips of low-growing vegetation and waiting for a host to pass by and brush the vegetation,” says Fredericks. Keep in mind a tick can be really patient, often waiting weeks or months for its next host to come along.

Handy tick locator: To find out which type of ticks live in your part of the country, check out this Tick Surveillance map from the Centers for Disease Control and Prevention (CDC).

Signs of Fleas vs. Ticks

Here’s how to determine whether you’re dealing with a flea or tick infestation.

Signs of Fleas

  • Pet scratching an irritated or infected spot;
  • Hair or fur loss;
  • Tiny black specks (flea feces) on the skin, pet beds, carpets or linens.

For humans, you may find itchy red bites around the feet and lower legs. “This is an easy jump for a flea to make from a dog to your leg,” says Kesheimer.

Signs of Ticks

Indications that your pet or you may have been bitten by a tick:

  • Sighting of an actual tick on you or your pet’s body;
  • You find ticks or their eggs in potted plants or elsewhere in the garden;
  • Your pet (or you) feels lethargic, with muscle weakness, loss of appetite, trouble breathing or vomiting.

Health Risks of Fleas vs. Ticks

Should you be concerned about health risks associated with fleas and ticks in your home?

For common fleas, Kesheimer says, “Not really.”

For the most part, flea bites can be itchy and annoying, but it’s rare they become a vector for diseases. A kind of tapeworm can be transmitted by fleas, but it’s rare and doesn’t generally cause serious health effects.

Ticks are another story.

In the U.S., Kesheimer says ticks are responsible for most vector-borne illnesses. The most common are Lyme disease and Rocky Mountain spotted fever.

Because tick-borne diseases can easily go undiagnosed and bring long-lasting consequences, it’s important to seek medical attention immediately if you suspect you’ve been bitten by a tick, aren’t feeling well or experiencing strange symptoms. Different species of ticks pose different threats to your health.

Fortunately, antibiotics can treat most tick-borne illnesses.

How To Get Rid of Fleas vs. Ticks

“It’s complicated,” says Kesheimer. “Since fleas are very small, you might not see them with your naked eye until there are a lot of them.” In the case of an infestation, she says you’ll likely notice tiny black specs jumping all around.

To get rid of fleas completely, you should:

  • Treat pets at the same time you treat the home;
  • Vacuum carpets, floors and upholstery frequently;
  • Wash bed linens, collars and plush toys in hot water;
  • Seal entry points around the perimeter of the home, since fleas can catch rides on rodents.
  • Look for flea larvae and spray with indoor insecticides, or try natural remedies.

The best way to reduce the number of ticks:

  • Check yourself and your pet before coming indoors;
  • Keep grasses and vegetation in the yard mowed and trimmed;
  • Spray an outdoor insecticide or repellent;
  • Remove ticks immediately (here’s how);
  • For a large infestation, call a pest control professional.

For ticks and fleas, talk to your vet about treatments and preventative options.

Toni DeBella
Toni DeBella is a culture and lifestyle writer, reviews expert and DIYer covering everything from pests to pool cabanas to painting. For over a decade, Toni was the owner of a successful faux finishing, mural and children’s furniture business before moving to a career in writing. Her work has appeared in The Telegraph, Fodor’s, Italy Magazine, DK Eyewitness travel guides and others. She lives in a medieval hill town in Italy where her bicycle “Raoul” serves as her primary mode of transportation.