Commensalism is a biological relationship between two species where one species benefits while the other is neither helped nor harmed. The species that benefits is called the commensal, and it may gain food, shelter, support, or transportation from the host species, which remains unaffected by the interaction

. This relationship is a type of symbiosis but differs from mutualism (where both benefit), parasitism (one benefits and the other is harmed), and amensalism (one is harmed while the other is unaffected)

. Common examples include:

• Remoras attaching to sharks to feed on leftover food without affecting the shark

• Birds like cattle egrets feeding on insects stirred up by grazing mammals without affecting the mammals

• Barnacles living on whales for transportation (phoresy)

There are different types of commensalism based on the nature of the interaction, such as inquilinism (living on or in another organism), metabiosis (using remains or structures left by another species), and phoresy (using another organism for transportation)

. The term "commensalism" comes from Latin roots meaning "sharing a table," reflecting the idea of one species benefiting by "eating at the same table" without affecting the other

. In summary, commensalism is a long-term ecological interaction where one species benefits and the other is neither helped nor harmed, often involving a larger host and a smaller commensal species