Animals are talking across species, and in some cases they are working together because of it.

New research published in Animal Behaviour found animals use calls, body movements, visual displays and other signals to coordinate cooperative relationships with other species. An international team of researchers reviewed examples from birds, fish, insects and mammals, and said these exchanges help animals synchronize their behaviour and maintain partnerships that benefit both sides.

Some birds lead humans to bees’ nests in exchange for access to beeswax. Cleaner fish remove parasites from larger reef fish and get a meal in return.

The researchers said cooperation often depends on animals matching the timing of their actions to reach a shared goal, even when the species involved perceive the environment differently.

One example is the greater honeyguide bird, Indicator indicator, which uses specialised calls to attract humans and lead them to bees’ nests. The bird also responds to calls made by humans.

In another case, warthogs use distinctive body postures to invite birds and mammals to clean them.

“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.”

The review found signals and behavioural cues also help animals identify trustworthy partners and reduce the risk of being exploited.

Some cleaner fish, including Labroides dimidiatus, and shrimp, including Urocaridella sp., display bright colours and perform distinctive movements that signal their role to predatory fish, allowing cleaning interactions to occur safely.

Lycaenid butterfly larvae use chemical and vibrational signals that encourage ants to protect them rather than eat them.

The researchers also said many species rely on information gathered through multiple senses, and that scientists may miss important forms of communication if they focus only on what animals can see.

The review found some communication systems stay highly consistent, while others vary with location and environmental conditions.

Fish seeking cleaning services often use predictable postures, such as headstands or tail stands. In contrast, fishermen working with dolphins may interpret different dolphin behaviours as cues for when to cast their nets, and those signals can vary from one region to another.

“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.”

The researchers also examined how communication systems between species may develop over time.

They said some signals may begin as simple cues, traits or behaviours that influence another animal’s response even though they were not originally meant to communicate information. Over generations, those cues can become more specialised signals.

Other communication signals may begin with different purposes, such as helping animals care for offspring or resolve conflicts, before being adapted for cooperative interactions between species.

“Studying how information flows between species gives us a powerful window into how communication systems originate, change and sometimes coevolve,” Dr Dunkley said.

The review grew out of an interdisciplinary workshop on interspecies cooperation held in Cambridge in July 2023. The paper has 58 authors from fields including anthropology, biology and linguistics.

It was published under the title, “The ecology and evolution of cues and signals in animal interspecies cooperation.”

“We still have much to learn about how these systems function and evolve,” Dr van der Wal said.

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