A. Boissy, G. Manteuffel, M. Jensen, R. Moe, B. Spruijt et al., Assessment of positive emotions in animals to improve their welfare, Physiology & Behavior, vol.92, issue.3, pp.375-397, 2007.
DOI : 10.1016/j.physbeh.2007.02.003

E. Palagi, T. Paoli, and S. Tarli, Short-Term Benefits of Play Behavior and Conflict Prevention in Pan paniscus, International Journal of Primatology, vol.109, issue.5, pp.1257-1270, 2006.
DOI : 10.1016/S0066-1856(68)80003-2

K. Finlayson, J. Lampe, S. Hintze, H. Würbel, and L. Melotti, Facial Indicators of Positive Emotions in Rats, PLOS ONE, vol.143, issue.2, p.27902721, 2016.
DOI : 10.1371/journal.pone.0166446.s006

J. Panksepp and J. Burgdorf, Laughing " rats and the evolutionary antecedents of human joy? Physiol Behav, pp.533-547, 2003.
DOI : 10.1016/s0031-9384(03)00159-8

URL : http://caspar.bgsu.edu/~courses/Reading/Papers/2003PanBur.pdf

C. Rochais, C. Fureix, C. Lesimple, and M. Hausberger, Lower attention to daily environment: a novel cue for detecting chronic horses??? back pain?, Scientific Reports, vol.40, issue.1, p.26823123, 2016.
DOI : 10.2746/042516407X240456

URL : https://hal.archives-ouvertes.fr/hal-01269908

J. Soltis, T. Blowers, and A. Savage, ), The Journal of the Acoustical Society of America, vol.129, issue.2, pp.1059-1066, 2011.
DOI : 10.1121/1.3531798

S. Gogoleva, I. Volodin, E. V. Volodina, A. V. Kharlamova, and L. Trut, Sign and strength of emotional arousal: vocal correlates of positive and negative attitudes to humans in silver foxes (Vulpes vulpes), Behaviour, vol.147, issue.13, pp.1713-1736, 2010.
DOI : 10.1163/000579510X528242

A. Anikin, R. Bååth, and T. Persson, Human Non-linguistic Vocal Repertoire: Call Types and Their Meaning, Journal of Nonverbal Behavior, vol.8, issue.1, pp.1-28
DOI : 10.1002/evan.21319

URL : https://link.springer.com/content/pdf/10.1007%2Fs10919-017-0267-y.pdf

E. Briefer, A. Maigrot, R. Mandel, S. Freymond, I. Bachmann et al., Segregation of information about emotional arousal and valence in horse whinnies. Sci Rep, pp.9989-25897781, 2015.

D. Sissom, D. Rice, and G. Peters, How cats purr, Journal of Zoology, vol.7, issue.No. 239, pp.67-78, 1991.
DOI : 10.5479/si.00810282.239

G. Peters, Purring and similar vocalizations in mammals, Mammal Review, vol.28, issue.4, pp.245-271, 2002.
DOI : 10.1007/978-1-4757-2405-9_19

J. Bradshaw, R. Casey, and S. Brown, The Behaviour of the Domestic Cat. CABI, 2012.

R. Policht, K. Tomasova, D. Holeckova, and D. Frynta, The vocal repertoire in Northern white rhinoceros ceratotherium simum cottoni as recorded in the last surviving herd, Bioacoustics. Taylor & Francis Group, vol.18, pp.69-969753591, 2008.

O. Montenegro, The behavior of Lowland Tapir (Tapirus Terrestris) at a natural mineral lick in the peruvian amazon, 1998.

D. Hunsaker and T. Hahn, Vocalization of the South American tapir, Tapirus terrestris Anim Behav Academic Press, pp.69-740003, 1965.
DOI : 10.1016/0003-3472(65)90073-4

S. Yeon, Acoustic communication in the domestic horse (Equus caballus), Journal of Veterinary Behavior: Clinical Applications and Research, vol.7, issue.3, pp.179-185, 2012.
DOI : 10.1016/j.jveb.2011.08.004

M. Kiley, The Vocalizations of Ungulates, their Causation and Function, Zeitschrift f??r Tierpsychologie, vol.19, issue.10, pp.171-222, 1972.
DOI : 10.1111/j.1439-0310.1967.tb01229.x

V. Durier, S. Henry, C. Sankey, J. Sizun, and M. Hausberger, Locomotor Inhibition in Adult Horses Faced to Stressors: A Single Postpartum Experience May be Enough!, Frontiers in Psychology, vol.3, issue.3, pp.442-23112783
DOI : 10.3389/fpsyg.2012.00442

URL : https://hal.archives-ouvertes.fr/hal-01020434

A. Lemasson, K. Remeuf, and M. Hausberger, Tenseness relaxed by vocalizing, illustrated by horses (Equus caballus) whinnying., Journal of Comparative Psychology, vol.129, issue.3, pp.311-315, 2015.
DOI : 10.1037/a0039032

URL : https://hal.archives-ouvertes.fr/hal-01193160

A. Lemasson, K. Remeuf, M. Trabalon, F. Cuir, and M. Hausberger, Mares Prefer the Voices of Highly Fertile Stallions, PLOS ONE, vol.28, issue.2, pp.118468-25714814
DOI : 10.1371/journal.pone.0118468.s006

URL : https://hal.archives-ouvertes.fr/hal-01120794

S. Briefer-freymond, E. Briefer, A. Zollinger, Y. Gindrat-von-allmen, C. Wyss et al., Behaviour of horses in a judgment bias test associated with positive or negative reinforcement, Applied Animal Behaviour Science, vol.158, pp.34-45, 2014.
DOI : 10.1016/j.applanim.2014.06.006

S. Löckener, S. Reese, M. Erhard, and A. Wöhr, Pasturing in herds after housing in horseboxes induces a positive cognitive bias in horses, Journal of Veterinary Behavior: Clinical Applications and Research, vol.11, pp.50-55, 2016.
DOI : 10.1016/j.jveb.2015.11.005

C. Douglas, M. Bateson, C. Walsh, A. Bédué, and S. Edwards, Environmental enrichment induces optimistic cognitive biases in pigs, Applied Animal Behaviour Science, vol.139, issue.1-2, pp.65-73, 2012.
DOI : 10.1016/j.applanim.2012.02.018

N. Reefmann, B. Kaszàs, F. Wechsler, B. Gygax, and L. , Ear and tail postures as indicators of emotional valence in sheep, Applied Animal Behaviour Science, vol.118, issue.3-4, pp.199-207, 2009.
DOI : 10.1016/j.applanim.2009.02.013

G. Arnaud, H. Dubroeucq, and D. Rivot, Notation de l'e ´tat corporel des chevaux de selle et de sport, Inra, 1997.

C. Fureix, M. Hausberger, E. Seneque, S. Morisset, M. Baylac et al., Geometric morphometrics as a tool for improving the comparative study of behavioural postures, Naturwissenschaften, vol.77, issue.15, pp.583-21573691, 2011.
DOI : 10.2527/1999.77suppl_21x

URL : https://hal.archives-ouvertes.fr/hal-01022143

C. Lesimple, C. Fureix, L. Aubé, and M. Hausberger, Detecting and Measuring Back Disorders in Nonverbal Individuals: The Example of Domestic Horses, Animal Behavior and Cognition, vol.3, issue.3, pp.159-179, 2016.
DOI : 10.12966/abc.05.08.2016

URL : https://hal.archives-ouvertes.fr/hal-01401459

C. Lesimple, C. Fureix, D. Margerie, E. Sénèque, E. Menguy et al., Towards a Postural Indicator of Back Pain in Horses (Equus caballus), PLoS ONE, vol.7, issue.9, p.22970261, 2012.
DOI : 10.1371/journal.pone.0044604.t004

URL : https://hal.archives-ouvertes.fr/hal-01020446

G. Mason, R. Clubb, N. Latham, and S. Vickery, Why and how should we use environmental enrichment to tackle stereotypic behaviour?, Applied Animal Behaviour Science, vol.102, issue.3-4, pp.163-188, 2007.
DOI : 10.1016/j.applanim.2006.05.041

URL : https://atrium.lib.uoguelph.ca/xmlui/bitstream/10214/4733/1/Mason_et_al._2007%20%28Why%20and%20how%20should%20we%20use%20environmental%20enrichment%20to%20tackle%20stereotypic%20behaviour%29.pdf

G. Mason and J. Rushen, Stereotypic animal behaviour: fundamentals and applications to welfare, Wallingford: CABI, 2008.
DOI : 10.1079/9780851990040.0000

M. Hausberger, E. Gautier, C. Müller, and P. Jego, Lower learning abilities in stereotypic horses, Applied Animal Behaviour Science, vol.107, issue.3-4, pp.299-306, 2007.
DOI : 10.1016/j.applanim.2006.10.003

URL : https://hal.archives-ouvertes.fr/hal-01319150

H. Benhajali, M. Ezzaouia, C. Lunel, F. Charfi, and M. Hausberger, Stereotypic behaviours and mating success in domestic mares, Applied Animal Behaviour Science, vol.153, pp.36-42, 2014.
DOI : 10.1016/j.applanim.2014.01.002

URL : https://hal.archives-ouvertes.fr/hal-01021538

J. Cooper, L. Mcdonald, and D. Mills, The effect of increasing visual horizons on stereotypic weaving: implications for the social housing of stabled horses, Applied Animal Behaviour Science, vol.69, issue.1, pp.67-83, 2000.
DOI : 10.1016/S0168-1591(00)00115-5

H. Benhajali, M. Richard-yris, M. Leroux, M. Ezzaouia, F. Charfi et al., A note on the time budget and social behaviour of densely housed horses, Applied Animal Behaviour Science, vol.112, issue.1-2, pp.196-200, 2008.
DOI : 10.1016/j.applanim.2007.08.007

URL : https://hal.archives-ouvertes.fr/hal-01319146

C. Lesimple and M. Hausberger, How accurate are we at assessing others??? well-being? The example of welfare assessment in horses, Frontiers in Psychology, vol.5, p.24478748, 2014.
DOI : 10.3389/fpsyg.2014.00021

URL : https://hal.archives-ouvertes.fr/hal-01021468

C. Fureix, H. Menguy, and M. Hausberger, Partners with Bad Temper: Reject or Cure? A Study of Chronic Pain and Aggression in Horses, PLoS ONE, vol.112, issue.4, p.20865160, 2010.
DOI : 10.1371/journal.pone.0012434.g005

URL : https://hal.archives-ouvertes.fr/hal-01019967

C. Fureix, M. Bourjade, S. Henry, C. Sankey, and M. Hausberger, Exploring aggression regulation in managed groups of horses Equus caballus, Applied Animal Behaviour Science, vol.138, issue.3-4, pp.216-228, 2012.
DOI : 10.1016/j.applanim.2012.02.009

URL : https://hal.archives-ouvertes.fr/hal-01021853

E. Rivera, S. Benjamin, B. Nielsen, J. Shelle, and A. Zanella, Behavioral and physiological responses of horses to initial training: the comparison between pastured versus stalled horses, Applied Animal Behaviour Science, vol.78, issue.2-4, pp.235-352, 2002.
DOI : 10.1016/S0168-1591(02)00091-6

M. Hausberger, H. Roche, S. Henry, and E. Visser, A review of the human???horse relationship, Applied Animal Behaviour Science, vol.109, issue.1, pp.1-24, 2008.
DOI : 10.1016/j.applanim.2007.04.015

URL : https://hal.archives-ouvertes.fr/hal-01319144

M. Hausberger and C. Muller, A brief note on some possible factors involved in the reactions of horses to humans, Applied Animal Behaviour Science, vol.76, issue.4, pp.339-344, 2002.
DOI : 10.1016/S0168-1591(02)00016-3

URL : https://hal.archives-ouvertes.fr/hal-01319157

C. Fureix, P. Jego, C. Sankey, and M. Hausberger, How horses (Equus caballus) see the world: humans as significant ???objects???, Animal Cognition, vol.40, issue.1, pp.643-654, 2009.
DOI : 10.1016/j.prevetmed.2005.02.002

URL : https://hal.archives-ouvertes.fr/hal-01354784

C. Rochais, S. Henry, and M. Hausberger, ???Hay-bags??? and ???Slow feeders???: Testing their impact on horse behaviour and welfare, Applied Animal Behaviour Science, vol.198, pp.52-59, 2018.
DOI : 10.1016/j.applanim.2017.09.019

S. Henry, M. Richard-yris, and M. Hausberger, Influence of various early human???foal interferences on subsequent human???foal relationship, Developmental Psychobiology, vol.35, issue.8, pp.712-718, 2006.
DOI : 10.1007/978-1-4613-3150-6

URL : https://hal.archives-ouvertes.fr/hal-01319152

S. Henry, D. Hemery, M. Richard, and M. Hausberger, Human???mare relationships and behaviour of foals toward humans, Applied Animal Behaviour Science, vol.93, issue.3-4, pp.341-362, 2005.
DOI : 10.1016/j.applanim.2005.01.008

URL : https://hal.archives-ouvertes.fr/hal-01358943

C. Fureix, P. Jégo, C. Coste, and M. Hausberger, Indicateurs de bien-être/mal-être chez le cheval: une synthèse. Les Haras Nationaux Available: https, pp.111-112, 2010.

K. Gleerup and C. Lindegaard, Recognition and quantification of pain in horses: A tutorial review, Equine Veterinary Education, vol.227, issue.1, pp.47-57, 2016.
DOI : 10.2460/javma.2005.227.281

S. Siegel and J. Castellan, Nonparametric statistics for the behavioral sciences, 1988.

G. Barlow, Ethological units of behaviour, The central nervous system and fish behaviour. D.Ingle. Chicago, pp.217-232, 1968.

J. Lee, T. Floyd, H. Erb, and K. Houpt, Preference and demand for exercise in stabled horses, Applied Animal Behaviour Science, vol.130, issue.3-4, pp.91-100, 2011.
DOI : 10.1016/j.applanim.2011.01.001

C. Tallet, P. Linhart, R. Policht, K. Hammerschmidt, S. ?. et al., Encoding of Situations in the Vocal Repertoire of Piglets
URL : https://hal.archives-ouvertes.fr/hal-01210431

D. Reby, PLoS One. Public Library of Science, vol.8, pp.71841-23967251, 2013.

G. Marx, J. Leppelt, and F. Ellendorff, Vocalisation in chicks (Gallus gallus dom.) during stepwise social isolation, Applied Animal Behaviour Science, vol.75, issue.1, pp.61-74, 2001.
DOI : 10.1016/S0168-1591(01)00180-0

C. Mccall, G. Potter, and J. Kreider, Locomotor, vocal and other behavioral responses to varying methods of weaning foals, Applied Animal Behaviour Science, vol.14, issue.1, pp.27-35, 1985.
DOI : 10.1016/0168-1591(85)90035-8

P. Hemsworth, M. Rice, M. Karlen, L. Calleja, J. Barnett et al., Human???animal interactions at abattoirs: Relationships between handling and animal stress in sheep and cattle, Applied Animal Behaviour Science, vol.135, issue.1-2, pp.24-33, 2011.
DOI : 10.1016/j.applanim.2011.09.007

E. Briefer, Vocal expression of emotions in mammals: mechanisms of production and evidence, Journal of Zoology, vol.80, issue.1, pp.1-20, 2012.
DOI : 10.1163/156853982X00409

J. Burgdorf, J. Panksepp, and J. Moskal, Frequency-modulated 50kHz ultrasonic vocalizations: a tool for uncovering the molecular substrates of positive affect, Neuroscience & Biobehavioral Reviews, vol.35, issue.9, pp.1831-1836, 2011.
DOI : 10.1016/j.neubiorev.2010.11.011

E. Zimmermann, Acoustic Communication in Nocturnal Prosimians Creatures of the Dark, pp.311-330, 1995.

R. Fontaine, The uakaris, genus Cacajao, Ecol Behav Neotrop Primates. Academia Brasileira de Cjiencias, pp.443-493, 1981.

J. Macedonia, The Vocal Repertoire of the Ringtailed Lemur (<i>Lemur catt</i><i>a</i>), Folia Primatologica, vol.61, issue.4, pp.186-217, 1993.
DOI : 10.1159/000156749

P. Winter, D. Ploog, and J. Latta, Vocal repertoire of the squirrel monkey (Saimiri sciureus), its analysis and significance, Experimental Brain Research, vol.1, issue.4, pp.359-384, 1966.
DOI : 10.1007/BF00237707

S. Linn, M. Boeer, and M. Scheumann, First insights into the vocal repertoire of infant and juvenile Southern white rhinoceros, PLOS ONE, vol.26, issue.7, pp.192166-29513670, 2018.
DOI : 10.1371/journal.pone.0192166.s001

A. Maigrot, E. Hillmann, C. Anne, and E. Briefer, Vocal expression of emotional valence in Przewalski's horses (Equus przewalskii) Sci Rep, pp.8779-28821880, 2017.

P. Li, W. Janczewski, K. Yackle, K. Kam, S. Pagliardini et al., The peptidergic control circuit for sighing, Nature, vol.54, issue.7590, pp.293-297, 2016.
DOI : 10.1006/bbrc.1997.7418

S. Soltysik and P. Jelen, In rats, sighs correlate with relief, Physiology & Behavior, vol.85, issue.5, pp.598-602, 2005.
DOI : 10.1016/j.physbeh.2005.06.008

F. Mcclernon, E. Westman, and J. Rose, The effects of controlled deep breathing on smoking withdrawal symptoms in dependent smokers, Addictive Behaviors, vol.29, issue.4, pp.765-772, 2004.
DOI : 10.1016/j.addbeh.2004.02.005