How many species of fleas exist worldwide? - briefly
Approximately 2,500 flea species have been formally described worldwide.
How many species of fleas exist worldwide? - in detail
Approximately 2,500 described flea species inhabit the planet. Taxonomic surveys place the order Siphonaptera within three major families—Pulicidae, Ceratophyllidae and Hystrichopsyllidae—each containing dozens of genera. The most diverse family, Ceratophyllidae, accounts for roughly one‑third of all known species, while Pulicidae includes many of the common ectoparasites of mammals and birds.
Geographic distribution reflects host availability rather than strict biogeographic borders. Species richness peaks in tropical regions where mammalian and avian biodiversity is highest; temperate zones host fewer taxa, often specialized on rodents or lagomorphs. Island ecosystems frequently harbor endemic flea species, sometimes limited to a single host species.
Current estimates arise from two sources:
- Published checklists and monographs compiled by entomologists (e.g., the “World Catalogue of Fleas”).
- Molecular studies that reveal cryptic diversity, suggesting that the true number of taxa may exceed 3,000.
The disparity between described and potential species underscores the need for continued field sampling and taxonomic revision, especially in understudied habitats such as rainforests and high‑altitude plateaus.