# The Complexity of Communication in Mammals: From Social and Emotional Mechanisms to Human Influence and Multimodal Applications

## TL;DR

This paper explores how mammals use various signals to communicate, how domestication has changed these signals, and how technology can improve animal care by understanding their communication.

## Contribution

The paper provides a comprehensive review of multimodal communication in mammals, emphasizing the impact of domestication and the role of modern technologies in animal welfare.

## Key findings

- Domestication has modified communication signals in animals like dogs and cats, making them more understandable to humans.
- Modern farming systems can hinder natural communication, making it harder to detect stress or discomfort in animals.
- Multimodal technologies like PLF and ACI can help monitor and improve the emotional and physical well-being of animals.

## Abstract

Mammals communicate with one another using many different signals, such as facial expressions, body posture, sounds, touch, and smells. These signals help them express emotions, avoid conflicts, build relationships, and function safely in social groups. Animals that live closely with humans, such as dogs, cats, horses, goats, and farm animals, have adapted their natural ways of communicating to interact more effectively with people. Domestication has changed how these species use their voice, eyes, body, and behaviour, making some signals clearer and easier for humans to understand. At the same time, modern farming systems can limit the natural exchange of signals and make it harder to recognise signs of stress or discomfort. This review explains how mammals communicate across different senses, how emotions shape their behaviour, and how human influence has changed these processes. It also shows how new technologies, such as continuous video and sound monitoring, can help detect pain, stress, or illness early, improving the care and welfare of animals. Understanding how animals send and receive signals allows people to respond more accurately to their needs, strengthens relationships with domestic species, and creates safer, kinder, and more ethical environments.

Communication in mammals constitutes a complex, multimodal system that integrates visual, acoustic, tactile, and chemical signals whose functions extend beyond simple information transfer to include the regulation of social relationships, coordination of behaviour, and expression of emotional states. This article examines the fundamental mechanisms of communication from biological, neuroethological, and behavioural perspectives, with particular emphasis on domesticated and farmed species. Analysis of sensory signals demonstrates that their perception and interpretation are closely linked to the physiology of sensory organs as well as to social experience and environmental context. In companion animals such as dogs and cats, domestication has significantly modified communicative repertoires ranging from the development of specialised facial musculature in dogs to adaptive diversification of vocalisations in cats. The neurobiological foundations of communication, including the activity of the amygdala, limbic structures, and mirror-neuron systems, provide evidence for homologous mechanisms of emotion recognition across species. The article also highlights the role of communication in shaping social structures and the influence of husbandry conditions on the behaviour of farm animals. In intensive production environments, acoustic, visual, and chemical signals are often shaped or distorted by crowding, noise, and chronic stress, with direct consequences for welfare. Furthermore, the growing importance of multimodal technologies such as Precision Livestock Farming (PLF) and Animal–Computer Interaction (ACI) is discussed, particularly their role in enabling objective monitoring of emotional states and behaviour and supporting individualised care. Overall, the analysis underscores that communication forms the foundation of social functioning in mammals, and that understanding this complexity is essential for ethology, animal welfare, training practices, and the design of modern technologies facilitating human–animal interaction.