An international team of researchers has published a new review in Animal Behaviour revealing how communication enables cooperation between different animal species. The review highlights how movements, visual displays, calls, and other behavioural cues and signals help partners coordinate interactions and align interests across species boundaries.
From birds guiding humans to bees' nests in return for access to beeswax, to cleaner fish removing ectoparasites from larger reef fishes in exchange for a meal: cooperation between species occurs across a remarkable range of ecological settings. By gathering examples from birds, fish, insects and mammals, the authors highlight the diverse ways that animals exchange information to organise their actions and sustain mutually beneficial partnerships.
Active teamwork between species
Cooperation between animal species requires individuals to coordinate the timing of their actions to achieve shared benefits, often across distinct sensory worlds. For example, the greater honeyguide bird (Indicator indicator) uses specialised calls to guide humans to bees' nests and responds to human calls in return, while warthogs actively solicit cleaning from bird and mammal cleaners through distinctive body poses.
"From the examples we know, individuals coordinate their actions to access shared resources, like food, or to exchange resources for services, such as protection from predators," said Dr Katie Dunkley, lead author and researcher at the University of Oxford. "We were particularly interested in how sharing information allows such close coordination between species."
Balancing benefits and risks
Cues and signals help animals identify cooperative partners, initiate interactions, and ensure they benefit from the partnership. Because interacting with members of another species can carry risks, communication is also important for avoiding individuals that might exploit them.
For example, some cleaner fish (e.g. Labroides dimidiatus) and shrimp (e.g. Urocaridella sp.) are brightly coloured and use distinctive body movements to safely clean predatory fish species, while lycaenid butterfly larvae employ chemical and vibrational signals to persuade ants to protect them instead of eating them. Many species rely on multiple senses to improve communication, and the review suggests that focusing only on obvious visual signals may overlook important ways animals exchange information across species.
Flexible communication
Some signals are stable and predictable, like the head or tail-stand postures of fish seeking cleaning services, while others vary across locations and ecological contexts, such as the dolphin behaviours fishermen interpret as indicators of when to cast their nets.
"In some forms of interspecies cooperation, cues and signals vary depending on the ecological context, the species involved, and whether the signal is inherited or learned," said senior author Dr van der Wal, a researcher affiliated with UCT's FitzPatrick Institute of African Ornithology. "This highlights just how flexible and adaptable interspecies communication can be."
Evolution of cooperation across species
The review also explores how communication systems between species may evolve. Some signals begin as simple cues, features or behaviours that influence how others respond, even though they did not originally evolve for communication. Over time, these cues can develop into clear signals. Other signals originate as behaviours used in different contexts, such as settling conflicts or caring for young, before being adapted for communication in interspecies cooperation.
"Studying how information flows between species gives us a powerful window into how communication systems originate, change and sometimes coevolve," said Dr Dunkley.
Collaborative effort
The review paper grew out of an interdisciplinary workshop on interspecies cooperation held in Cambridge in July 2023, where researchers studying a wide variety of systems came together. The paper includes 58 authors spanning multiple disciplines, including anthropology, biology and linguistics, as well as researchers studying animal interspecies cooperation, mixed-species behaviours and systems where humans actively train non-human animals.
Future directions
The review opens new avenues for studying the evolution of communication across species boundaries and the ecological importance of interspecies cooperation. It also highlights the need for broader studies across taxa and more experimental work to understand how signals emerge, persist and shape cooperative behaviour.
"We still have much to learn about how these systems function and evolve," said Dr van der Wal. "We look forward to future research revealing both these interactions and other forms of interspecies cooperation yet to be discovered."
Publication details
The research appears in Animal Behaviour under the title: "The ecology and evolution of cues and signals in animal interspecies cooperation."
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Videos and photographs illustrating the examples of animal interspecies cooperation discussed in the paper are available here:
Please refer to the accompanying Excel file for the appropriate captions and descriptions.
