Harri Roblin

Vocal communication is an integral part of animal behaviour. It informs on many animal interactions that were previously unknown. For years, many theories were hypothesised on communication within animals. It has widespread application throughout the animal kingdom, making it vital for scientists to understand to rationalise species interactions. For centuries, scientists did not have the equipment to study animal calls truly. However, modern-day technology can now distinguish all the components of communication from pitch to frequency. The ability to determine the minute changes in calls has revealed many previously unknown interactions.

Vocal communication has helped us understand why animals live in groups rather than alone. There are many negatives to living in a group if you look at the surface level. For example, living in close proximity will cause greater competition which could lead to losing paternity opportunities or a lack of access to essential resources. Despite this, lots of species decide to live in groups. The study of vocal communication has helped us to understand why this is the case. The benefits of groups far outweigh the cons for most species, with breeding, searching for food and vigilance against predators being much more effective using vocal communication. Several specific examples illustrating these benefits will be listed below.

The process of foraging and hunting for food is now much better understood due to the study of vocal communication. Herbivores orally communicate to feed much more efficiently. Not only do they find more food, but they also expend less energy, meaning their survival chances rise dramatically. A study by (Jackson and Ratnieks, 2006) found that ants use oral communication to forage. However, they found that calls were not only used to show where food was but also to regulate foraging activity and recall locations of previous foraging success. Previously, it was thought that ants only use odour trails to find food, but this research into vocal communication opened a whole new perspective on the ants’ foraging behaviour.

Carnivores also use vocal communication to aid their chances of a successful hunt. For example, the foraging seabird Cape gannet was studied (Andréa Thiebault et al., 2019). Miniaturised audio-recording devices allowed scientists to measure their oral calls while foraging. They found that gannets use their calls to identify the position they find food, whether that be flying, sitting on the water or diving. This increased their foraging success significantly and showed the benefits of foraging in a group. The ability to distinguish between their calls allowed for a greater understanding of their methods of foraging and also their behaviour.

Calling regarding food can be dangerous for animals as it might give their position away to possible predators. However, studies have also shown that vocal communication can be successfully used to detect predators and flee to safety. This allows for much faster detection of these predators due to increased vigilance, significantly increasing their chance of survival. An example of this is the Cape ground squirrel. A study by (Furrer and Manser, 2009) found that these squirrels ‘emitted urgency-dependent alarm calls’ which contained all essential information regarding the threat level of the predator and coordinating group movements. They compared this to meerkats, who relied more on vigilance and escape behaviour. By studying both the species’ vocal communications, the scientists concluded that this was due to the squirrels living and foraging in a smaller area than the meerkats. This gave a critical insight into explaining the general behaviour of both animals and a more comprehensive understanding of predator avoidance.

However, this behaviour can be manipulated by other species. The fork-tailed drong often lives in similar habitats to meerkats and has similar diets. This bird will first gain the trust of the meerkats by performing some reliable alarm calls. It will start to signal dishonestly after it has earned the meerkat’s trust. If a meerkat finds food, the drong will alarm call and make the meerkats retreat to their burrows for protection. This will then leave the food available for the drong to fly down and pick up. This is an example of a behaviour where verbal signalling is used to take advantage of a species.

The study of vocal communication has not only shown the deterrence of predators but also that animals mark their territory orally. The hooded warbler is an example of this. Scientists looked at the different types of calls the male warbler performed. Upon inspection, they found the warbler used a ‘metallic-sounding chink call’ to warn away possible intruders (Owings et al., 1998). If this did not work, the warbler would make ‘harsh gowling sounds’ while chasing the intruder. This study helped to understand the importance of verbal communication, even though hostile, in defending a territory.

The meerkat is another example of this. They use a technique called mobbing, where they noisily gather around a potential predator. This is an example of an animal using vocal communication to intimidate another animal such as a snake. However, a study by (Graw and Manser, 2007) found that this behaviour was not just trying to intimidate a predator. When presented with animals they had not yet encountered, meerkats would mob to determine their potential risk. This behaviour would stop if the meerkats realised the animal did not threaten them. A study by (Gall and Manser, 2017) found that foraging meerkats combine vocally to create a hot spot. This helps to maintain cohesion and in difficult weather conditions, can keep the group together when they cannot see each other. This is an example of how looking at vocal communication can gather information about why animals make certain noises and behaviours.

Studying the audio of animals can also give insight into animals mating rituals and the process of choosing a mate. Many animals use vocal communication to attract mates. An example of this is frogs, where many males will gather at a pond ‘breeding site’. They will then compete acoustically against each other. The female will pick the male based on their verbal cues (Kelley, 2004). However, it is sometimes not as simple as that. In frog mating, there are two types of males, callers and satellites. The bigger frogs with the best vocal cues will be more at the central part of the pond as a caller. Females will be travelling to these calls, but get intercepted by a satellite frog at the edge of the pond. Satellites cannot compete vocally with callers. Therefore, they have a much high breeding success intercepting the females. The study of the vocal behaviour of these frogs when mating has led to these findings, which shows a crucial insight into their behaviour.

As stated in the introduction, many variables about an animal’s call can be analysed. These can then be decoded to discover the reason behind the call. For example, a very repetitive call could point to it being redundant, whereas the frequency or pitch of a call could directly correlate with breeding success. It can also tell you a lot about the anatomy of animals. For example, elephants produce a lower frequency rumble because it travels longer distances and because their ear anatomy is designed for lower frequencies. This is very helpful in explaining possible behaviours.

Not only can it be used to show anatomy, but it can also help distinguish between two similar species. For example, icterine and melodious warblers look very similar, so they are hard to tell apart. However, when the sound of their songs is analysed, their components are entirely different. It is essential to be able to identify the species when studying animal behaviour, as even though they might look similar, they could have completely different backgrounds. Bird song can also tell you about a birds breeding status, age and health. This is, therefore, another example of how vocal communication can be beneficial in explaining animal behaviours.

Vocal communication has helped us understand how animals distinguish their offspring and kin. A study by (Sharp et al., 2005) found that long-tailed tits could detect the call of one of their kin. In this species, most of the helpers to a mother are her brothers. It used to be unknown how they recognised their kin. The study into their ‘churr’ call found that each bird had a unique maximum and minimum frequency which members of the same species could recognise. However, these calls can be exploited. For example, adult cuckoos often replace the host’s eggs with their own. They have evolved to mimic the chick of their host to make acceptance much more likely. The cuckoo chicks often make substantial noise to trick the parent into thinking there are more chicks. This raises the provision rate of food and allows them to grow healthily. This is a fascinating study of how vocal communication can be used to trick other species and alter their behaviours.

Climate change is one of the most significant environmental stresses currently, so it is important to look at how it has affected animal behaviour. Studying vocal communication can help us to do this. A study by (Fuller et al., 2007) found that due to anthropogenic influences, the European robin now sings more at night than during the day. Urbanisation means this songbird has too much competition for noise during the day, so it has to shift to the quieter night. A similar finding has occurred with great tits. The louder noise now means they must sing at a higher pitch (Slabbekoorn and Peet, 2003). This could be devastating for animals that rely on the most minute changes in their song to communicate. Studying both the time and frequency of these birds’ calls has given a good insight into their behaviour.

Finally, vocal communication can explain how certain behaviours are passed on from generation. A study by (Burkart et al., 2022) looked at how marmoset monkeys interacted. They found that the primates were able to perform vocal learning. Further studying of their calls showed that infants actually babble between each other and finally hum when they are happy. All these are very interesting in not only studying animal behaviour but also looking at how infants learn.

To conclude, the study of vocal communication has given some crucial insights into animal behaviour. Many animal behaviours are performed acoustically and cannot be seen by the human eye. It is, therefore, crucial that the study of calls and communications between animals of the same species is continued so their behaviour can be more well understood. With climate change becoming an increasing problem, it is important to utilise vocal communication study to identify changes in animal behaviour.