Clean thy neighbor: the mutualistic interaction between the cattle tyrant and the capybara

Cleaning symbiosis is an ecological phenomenon characterized by a mutually beneficial relationship between two species, where one individual (known as the cleaner) removes external parasites, debris, or other unwanted material from the body of the host (referred to as the client). One remarkable example of cleaning symbiosis involves the interaction between birds and capybaras, as shown by the photograph. Capybaras (Hydrochoerus hydrochaeris) are large rodents that inhabit wetlands, such as the Brazilian Pantanal, where they are exposed to numerous ectoparasites, including ticks and lice. In these settings, certain bird species, such as the cattle tyrant (Machetornis rixosa), take on the role of cleaners by landing on the capybara's body, picking the parasites, and consuming them. Interestingly, this cleaning symbiosis is not merely a one-way interaction. Capybaras also play an active role by lying on the ground and exposing their heads, backs, and bellies, thereby allowing the birds easy access to body parts that would not be reached otherwise (Biota Neotrop 2010; https://doi.org/10.1590/S1676-06032010000100028).