Fleas are ectoparasites, meaning they live on the outside of their hosts, typically feeding on the blood of mammals and birds. While fleas primarily rely on a host for their blood meals and reproduction, they can survive for varying lengths of time without one, depending on environmental conditions.
Under ideal conditions (such as high humidity and moderate temperatures), adult fleas can survive for several weeks to several months without feeding on a host. However, they can't reproduce or lay eggs without access to blood, so their population won't increase during this time.
In less favorable conditions (such as low humidity or extreme temperatures), adult fleas may only survive for a few days to a week without a host.
It's important to note that flea eggs, larvae, and pupae can also survive in the environment (such as carpets, bedding, and outdoor areas) for varying lengths of time, contributing to ongoing infestations even when adult fleas are not present on a host. Therefore, it's crucial to address both the adult fleas and their environmental stages when treating flea infestations.