Quick answer
Fleas are tiny, wingless insects that live as parasites on the bodies of mammals and birds, feeding on their blood. They are renowned for their jumping ability, able to leap many times their own body length thanks to powerful hind legs and a spring-like protein. Fleas can be a nuisance to pets and people and can transmit disease, and they are found nearly worldwide.
Key takeaway
Fleas are tiny, wingless insects that live as parasites on the bodies of mammals and birds, feeding on their blood. They are renowned for their jumping ability, able to leap many times their own body length thanks to powerful hind legs and a spring-like protein. Fleas can be a nuisance to pets and people and can transmit disease, and they are found nearly worldwide.
Overview
Fleas are tiny, wingless insects that live as parasites on the bodies of mammals and birds, feeding on their blood. They are renowned for their jumping ability, able to leap many times their own body length thanks to powerful hind legs and a spring-like protein. Fleas can be a nuisance to pets and people and can transmit disease, and they are found nearly worldwide.
Biology
Flea (Siphonaptera) is classified as Insect with conservation status Least Concern. Typical weight about 5e-7 kg; lifespan around Several weeks to a few months.
Ecology
Diet: Hematophagous (blood of mammals and birds). Habitat: On the bodies of host animals worldwide. Movement and social systems reflect those pressures.
People and this species
Learn before you travel or keep related pets. Wild individuals are not toys; captive care needs species-specific husbandry.
Further reading
See the full Flea profile for FAQs, taxonomy, and related guides on this site.
Built for jumping
Fleas are famous for their extraordinary jumps, able to leap distances and heights many times their own body length. The power comes from a rubber-like protein called resilin that stores energy and releases it like a spring. This lets a flea launch onto a passing host with explosive acceleration.
A parasitic lifestyle
Fleas are external parasites that feed on the blood of mammals and birds, with each species often favoring particular hosts. Their bodies are flattened from side to side, helping them slip easily through fur and feathers, and backward-pointing bristles make them hard to remove. Mouthparts adapted for piercing skin let them feed on blood.
Life cycle
A flea's life cycle moves through egg, larva, pupa, and adult, much of it taking place off the host in bedding, carpets, or nests. Eggs laid on a host often fall into the surrounding environment, where the larvae feed on debris before pupating. Adults emerge ready to jump onto a host and feed, sometimes after waiting for the right cue such as warmth or vibration.
Fleas and disease
Beyond the irritation of their bites, fleas can transmit diseases and parasites. Historically, certain fleas spread the bacteria responsible for plague, and fleas can also carry tapeworms and other pathogens between animals. Controlling fleas on pets and in the home helps protect both animals and people.
Research notes
Figures for fleas (Siphonaptera) come from field studies, museum records, and conservation assessments that do not always agree on exact averages. Prefer ranges over single-point claims, and check whether a source describes wild, captive, or mixed populations.
Practical takeaways
If you encounter fleas in the wild, prioritise distance and local guidance. If you care for related domestic or captive animals, match diet and housing to species needs rather than generic pet advice. Share accurate status information (Least Concern) when discussing conservation.
Sources
FAQs
Flea: Key Facts & Natural History?
Fleas are tiny, wingless insects that live as parasites on the bodies of mammals and birds, feeding on their blood. They are renowned for their jumping ability, able to leap many times their own body length thanks to powerful hind legs and a spring-like protein. Fleas can be a nuisance to pets and people and can transmit disease, and they are found nearly worldwide.
What is the scientific name of the flea?
Siphonaptera
What do fleas eat?
Hematophagous (blood of mammals and birds)
Where do fleas live?
On the bodies of host animals worldwide
Are fleas endangered?
Listed here as Least Concern. Check IUCN and national lists for the latest assessment.