Fleas are a constant annoyance for cat and dog owners; several billion dollars are spent every year worldwide on flea and tick treatments. While their bites generally cause nothing more than itching and pain, they have been known to transmit diseases to people. They were largely responsible for the transmission of the bubonic plague from rats to humans in the Middle Ages. People can also develop allergies to repeated bites. Fleas normally take avian or mammalian hosts, but some species infest reptiles as well. This article will cover some interesting facts about the identification, prevention, habitat, and diet of the common flea.
3 Incredible Flea Facts
- Fleas are extremely tough. They may have evolved to withstand immense pressures when the host tries to crush them.
- Fleas pass through four different life stages: eggs, larvae, pupae, and adults. The larval stage involves a series of three molts to grow progressively larger, while during the pupa stage, they weave a silk cocoon to transform into an adult. It takes about three to four weeks to reach the adult stage. They can live anywhere from a few days to several weeks, and up to three months in optimal conditions.
- One of the most interesting facts is that fleas can leap up to 7 inches vertically and 13 inches horizontally. Given their small size, it’s one of the most impressive jumpers relative to body size in the entire animal kingdom.
Evolution and Origins
Fleas, contrary to common assumption, are taxonomically classified as scorpionflies. Their evolution can be traced back to the period between the Permian and Jurassic, approximately 290 to 165 million years ago, when they began to feed on the blood of vertebrates.
It is believed that modern fleas likely originated in the southern region of the Gondwana supercontinent and subsequently migrated swiftly toward the north.
Their evolution is thought to have initially occurred in association with mammalian hosts, with the transition to avian hosts happening at a later stage.
Species, Types, and Scientific Names

The flea order is scientifically known as Siphonaptera, which originates from the fusion of two Greek terms: “siphon,” referring to their tube-like blood-sucking apparatus, and “apteros,” indicating their lack of wings.
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The flea order is scientifically known as Siphonaptera. This is derived from the combination of two Greek words: siphon, meaning tube (their blood-sucking apparatus), and apteros, meaning wingless. There are over 2,500 species of fleas spread across more than 240 genera. Some of the most common types include cat fleas, bird fleas, and rat fleas.
Appearance: How to Identify Them
Fleas are small wingless insects, rarely measuring more than an eighth of an inch long. The small size can sometimes make identification difficult, but adults are characterized by black or brown bodies, bulbous or rounded at the back, with hard plates and various hairs and bristles directed backward. A long proboscis emerging from the mouth enables them to pierce the skin and suck the blood of their host. Their long legs are well-adapted for jumping and are also covered in strong claws that grasp the host’s body. Brown or black fleas often turn a shade of red after sucking up blood.
The larvae, by contrast, look nothing like the adult. They have a long segmented worm-like body with short bristles instead of legs, no eyes, and mouthparts adapted for chewing. When the larva grows large enough to transform, it will often seek out dark spaces anywhere in the house or on the ground and then weave its cocoon. Some species can actually delay their development until they sense a host nearby. Vibrations, body heat, or carbon dioxide exhaled from a nearby animal are often triggers for the pupa to emerge from the cocoon and attach to the host.

Ceratophyllus gallinae, known as the hen flea or European chicken flea. It is an ectoparasite of birds that commonly attacks poultry and can bite humans and other mammals.
©iStock.com/S.Rohrlach
Habitat: Where to Find Them
Fleas are found in almost all ecosystems around the world. As mentioned previously, they live on the body of a host. Some species are specialized for a specific host (like a cat or a rabbit), while others will accept multiple hosts.
Diet: What Do Fleas Eat?
Fleas rely completely on their host for their diet. The host provides nearly all of the organic matter they need to survive.
What eats the flea?
Fleas are often preyed upon by other insects, spiders, lizards, snakes, and frogs.
What does the flea eat?
The adult flea feeds exclusively on blood; the technical term for a blood-feeding animal is hematophage. They typically have 10 to 15 blood feedings per day. The larvae, on the other hand, feed on skin flakes, dead mites, dried excrement, blood, and other bits of organic matter. The pupa does not usually eat at all until it emerges from the cocoon.
Prevention: How to Get Rid of Them

Pet owners should regularly check their cats and dogs for fleas.
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Fleas are most likely to enter the home by taking a pet as a host. Both cat and dog owners should be especially vigilant for signs of infestation in the house. In order to treat your pet, a veterinarian will recommend either an oral insecticide in capsule or tablet form or a topical insecticide applied between the shoulder blades. Depending on the product, this should kill adult fleas or prevent them from reproducing for one to three months.
Once your pet has received its treatment, you should use a powerful vacuum or steam cleaner on the bedding, carpets, floors, and upholstery every day (especially where you know your pet has been) for several weeks. The vacuum bag should be disposed of immediately after each use to prevent the fleas from immediately returning. Wash the infested bedding in hot water and dry it at the highest possible heat setting.
Finally, you can use an aerosol spray (preferably not a fogger) to ensure any remaining fleas are killed. Chemicals like permethrin normally work for adults, while methoprene or pyriproxyfen will work as a form of pest control for the egg, larva, or pupa stage. Pets can pick up fleas from your yard, so make sure there isn’t any tall grass or debris where the insects can hide (they do not usually stay in exposed areas). Check the area where your pet has just been around the yard. Employing all of these strategies at once will help with the prevention of any future infestations.
Flea Pictures
View all of our Flea pictures in the gallery.
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Sources
- Britannica / Accessed December 17, 2021
- Terminix / Accessed December 17, 2021
- Health Line / Accessed December 17, 2021