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Die Naturwissenschaften2026; 113(4); 79; doi: 10.1007/s00114-026-02113-3

Could snort production reflect comfort in horses kept outdoors? A first study.

Abstract: The welfare of free-roaming, captive wild or domestic animals housed outdoors is often questioned. How subjects perceive climatic conditions is not always well detected as it is highly subjective, depending on species, age and experience. Hence, decisions on housing rely mostly on human anthropomorphic perception. In particular, indicators of comfort and positive emotions remain poorly documented. Acoustic signals, however, offer a promising window into animals' internal states. In the present study, we hypothesized that acoustic signals could be used to identify positive or negative perceptions of environmental conditions in horses. Horses possess a diverse acoustic repertoire and the snort produced by nostril vibration, has been identified as a likely indicator of calm, positive emotions. Over 3 weeks in early spring, acoustic production and time budget were recorded for 20 adult horses living outdoors on pasture. Meteorological conditions and pasture composition were monitored simultaneously. Results showed that snorts were the most frequent acoustic signal and that their production varied considerably across observation sessions. Snort production was highly correlated with temperature: horses produced more snorts and showed more relaxed behaviours when the temperature ranged between 15 and 20 °C. In contrast, lower temperatures around 5-8 °C were associated with more "static" behaviours (reflecting energy conservation) and less snorts. Finally, snorts were more frequent immediately after horses entered a new pasture with higher food diversity than just before leaving, when food diversity had become more restricted. These findings suggest that acoustic production may help identify the subjective perception that animals have from their environment, allowing more individualized and adapted management practices.
© 2026. The Author(s).
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Publication Date: 2026-06-30 PubMed ID: 42377502PubMed Central: PMC13320096DOI: 10.1007/s00114-026-02113-3Google Scholar: Lookup
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Summary

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Overview

  • This study investigates whether the production of snorts, an acoustic signal in horses, can be an indicator of comfort and positive emotional states in horses kept outdoors.
  • The research explores the relationship between snort frequency, environmental conditions, and horse behavior to assess if snort production reflects the horses’ subjective perception of their environment.

Introduction and Background

  • Welfare concerns are common for free-roaming, captive wild, and domestic animals housed outdoors.
  • Animals’ comfort and emotional states are difficult to measure because perceptions of climatic conditions vary by species, age, and individual experience.
  • Human decisions about animal housing often rely on anthropomorphic bias, lacking objective indicators of animal comfort and positive emotions.
  • Acoustic signals provide a promising method for inferring internal emotional states of animals, as they can reflect mood and perception of the environment.
  • Horses produce a range of acoustic signals; among them, the snort—caused by nostril vibration—has been proposed as a sign of calmness and positive emotional states.

Research Hypothesis

  • The study hypothesizes that the frequency and conditions of snort production by horses correspond to their positive or negative perception of the environment they are in.
  • The researchers aimed to test if snorts correlate with environmental comfort indicators, such as temperature and pasture quality, and with relaxed or energy-conserving behaviors.

Methodology

  • Subjects: 20 adult horses living outdoors on pasture.
  • Duration: Observations conducted over 3 weeks in early spring.
  • Data collected included:
    • Acoustic recordings to capture snorts and other sounds made by horses.
    • Behavioral time budgets, noting relaxed vs. static/energy conservation behaviors.
    • Meteorological conditions, primarily temperature, were monitored.
    • Pasture composition and food diversity to gauge environmental quality.

Key Findings

  • Snorts were the most frequent acoustic signal detected during observations.
  • Snort frequency varied significantly between observation sessions.
  • Temperature was strongly correlated with snort frequency:
    • More snorts and relaxed behaviors occurred at temperatures between 15 and 20 °C.
    • Lower temperatures (around 5–8 °C) were associated with fewer snorts and an increase in static behaviors, which likely indicate energy conservation due to less comfort.
  • Snort production also changed with pasture quality:
    • More snorts were produced immediately after horses entered a new pasture that had higher food diversity.
    • Fewer snorts were observed just before horses left the pasture when food diversity was reduced.

Interpretation and Implications

  • Higher snort rates correspond to temperature ranges and environmental conditions that favor comfort and relaxation in horses.
  • Lower snort rates in colder temperatures and less food-diverse settings suggest discomfort or less positive affective states.
  • Snorts may therefore serve as an acoustic marker of the horses’ subjective experience of comfort and positive emotions.
  • This insight opens up new opportunities to use vocalization monitoring as a non-invasive welfare assessment tool in horses and potentially other species.
  • It supports the development of individualized and adaptive animal management and housing practices based on objective behavioral and acoustic indicators rather than just human perception.

Conclusion

  • The study provides initial evidence that snort production in horses can reflect their comfort and positive emotional perception in an outdoor environment.
  • Further research could refine this approach and extend it to other species and contexts for enhancing animal welfare assessments.

Cite This Article

APA
Hausberger M, Matthieu L, Delbos M, Briseño-Jaramillo M, Wimel L, Henry S, Lemasson A, Lesimple C. (2026). Could snort production reflect comfort in horses kept outdoors? A first study. Naturwissenschaften, 113(4), 79. https://doi.org/10.1007/s00114-026-02113-3

Publication

Die Naturwissenschaften
ISSN: 1432-1904
NlmUniqueID: 0400767
Country: Germany
Language: English
Volume: 113
Issue: 4
PII: 79

Researcher Affiliations

Hausberger, Martine
  • Department of Zoology and Entomology, Rhodes University, Makhanda, South Africa.
  • Centre Intégratif de Neuroscience et Cognition, Université de Paris-Cité, UMR CNRS 8002, Paris, France.
Matthieu, Lucas
  • Centre d'étude en éthologie et cognition, Université de Rennes, Université de Caen-Normandie, UMR CNRS 6552, Paimpont, France.
Delbos, Maëlle
  • Centre d'étude en éthologie et cognition, Université de Rennes, Université de Caen-Normandie, UMR CNRS 6552, Paimpont, France.
Briseño-Jaramillo, Margarita
  • Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Mexico. mar.briseno.jaramillo@gmail.com.
Wimel, Laurence
  • IFCE, Station Expérimentale de Chamberet, Chamberet, France.
Henry, Séverine
  • Centre d'étude en éthologie et cognition, Université de Rennes, Université de Caen-Normandie, UMR CNRS 6552, Paimpont, France.
Lemasson, Alban
  • Centre d'étude en éthologie et cognition, Université de Rennes, Université de Caen-Normandie, UMR CNRS 6552, Paimpont, France.
Lesimple, Clémence
  • Centre d'étude en éthologie et cognition, Université de Rennes, Université de Caen-Normandie, UMR CNRS 6552, Paimpont, France.
  • Ecole Supérieure des Agricultures (ESA), USC URSE - Unité de Recherche sur les Systèmes d'Elevage - Ecole Supérieure des Agricultures, Angers, France.

MeSH Terms

  • Animals
  • Horses / physiology
  • Housing, Animal
  • Temperature
  • Animal Welfare
  • Female
  • Animal Husbandry
  • Behavior, Animal / physiology
  • Vocalization, Animal / physiology
  • Thermal Comfort

Conflict of Interest Statement

Declarations. Compliance with ethical standards: The study was carried out in 2016 in accordance with the European Parliament and the European Union Council directive 2010/63/UE relative to the protection of animals used for scientific purposes and complied with the current French laws related to animal experimentation (Decree no. 2013 − 118 of 1 February 2013) and its five implementation orders (JO of 7 February 2013), integrated in the Code rural and the Code of the maritime fishing under no. R. 214 − 87 à R. 214 − 137). Being only observational, our study did not require any further ethical authorization. The private owner of the riding school allowed our research to be conducted on his site. Animal husbandry and care were under the management of the riding school staff. Competing interests: The authors declare no competing interests.

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