J. Altmann, Observational Study of Behavior: Sampling Methods, Behaviour, vol.49, issue.3, pp.227-267, 1974.
DOI : 10.1163/156853974X00534

R. Baenninger, Some comparative aspects of yawning in Betta splendens, Homo sapiens, Panthera leo, and Papio sphinx., Journal of Comparative Psychology, vol.101, issue.4, pp.349-354, 1987.
DOI : 10.1037/0735-7036.101.4.349

R. Baenninger, On yawning and its functions, Psychonomic Bulletin & Review, vol.316, issue.6, Pt. 2, pp.198-207, 1997.
DOI : 10.3758/BF03209394

R. Baenninger, S. Binkley, and M. Baenninger, Field observations of yawning and activity in humans, Physiology & Behavior, vol.59, issue.3, pp.421-425, 1996.
DOI : 10.1016/0031-9384(95)02014-4

R. Baenninger and M. Greco, Some antecedents and consequences of yawning, Psychol Rec, vol.41, pp.453-460, 1991.

B. Beerda, M. Schilder, J. Van-hooff, H. De-vries, and A. Mol, Behavioural and hormonal indicators of enduring environmental stress in dogs, Anim Welf, vol.9, pp.49-62, 2000.

H. Berendsen and V. Nickolson, Androgenic influences on apomorphine-induced yawning in rats, Behavioral and Neural Biology, vol.33, issue.1, pp.123-128, 1981.
DOI : 10.1016/S0163-1047(81)92306-2

J. Berger, C. Blois-heulin, C. Rochais, S. Camus, C. Fureix et al., Wild horses of the Great Basin: social competition and population size Animal welfare: could adult play be a false friend, Anim Behav Cogn, vol.2, pp.156-185, 1986.

M. Bourjade, L. Tatin, S. King, and C. Feh, Early reproductive success, preceding bachelor ranks and their behavioural correlates in young Przewalski's stallions, Ethology Ecology & Evolution, vol.21, issue.1, pp.1-14, 2007.
DOI : 10.1080/08927014.2009.9522507

K. Chambers and C. Phoenix, Diurnal patterns of testosterone, dihydrotestosterone, estradiol, and cortisol in serum of rhesus males: Relationship to sexual behavior in aging males, Hormones and Behavior, vol.15, issue.4, pp.416-426, 1981.
DOI : 10.1016/0018-506X(81)90006-4

J. Christensen, T. Zharkikh, J. Ladewig, and N. Yasinetskaya, Social behaviour in stallion groups (Equus przewalskii and Equus caballus) kept under natural and domestic conditions, Applied Animal Behaviour Science, vol.76, issue.1, pp.11-20, 2002.
DOI : 10.1016/S0168-1591(01)00208-8

B. Deputte, Study of yawning in two species of Cercopithecidae; Cercocebus albigena albigena gray and Macaca fascicularis raffles: research on causal and functional factors; a consideration of socio-bioenergetic factors, 1978.

B. Deputte, Ethological Study of Yawning in Primates. I. Quantitative Analysis and Study of Causation in Two Species of Old World Monkeys (Cercocebus albigena and Macaca fascicularis), Ethology, vol.18, issue.3-4, 1994.
DOI : 10.1111/j.1439-0310.1994.tb01073.x

B. Deputte, J. Johnson, M. Hempel, and G. Scheffler, Behavioral Effects of an Antiandrogen in Adult Male Rhesus Macaques (Macaca mulatta), Hormones and Behavior, vol.28, issue.2, pp.155-164, 1994.
DOI : 10.1006/hbeh.1994.1013
URL : https://hal.archives-ouvertes.fr/hal-01368787

N. Dreschel and D. Granger, Physiological and behavioral reactivity to stress in thunderstorm-phobic dogs and their caregivers, Applied Animal Behaviour Science, vol.95, issue.3-4, pp.153-168, 2005.
DOI : 10.1016/j.applanim.2005.04.009

P. Duncan, Time-Budgets of Camargue Horses Ii. Time-Budgets of Adult Horses and Weaned Sub-Adults, Behaviour, vol.72, issue.1, pp.26-48, 1980.
DOI : 10.1163/156853980X00023

C. Feh, Social behaviour and relationships of Prezewalski horses in Dutch semi-reserves, Applied Animal Behaviour Science, vol.21, issue.1-2, pp.71-87, 1988.
DOI : 10.1016/0168-1591(88)90101-3

A. Fundaro, Chronic nimodipine and yawning behaviour in grouped or individually housed rats, Progress in Neuro-Psychopharmacology and Biological Psychiatry, vol.20, issue.1, pp.121-127, 1996.
DOI : 10.1016/0278-5846(95)00297-9

C. Fureix, A. Górecka-bruzda, E. Gautier, and M. Hausberger, ), ISRN Zoology, vol.86, issue.3-4, pp.1-10, 2011.
DOI : 10.1006/hbeh.1994.1013

A. Gallup and G. Gallup, Yawning as a Brain Cooling Mechanism: Nasal Breathing and Forehead Cooling Diminish the Incidence of Contagious Yawning, Evolutionary Psychology, vol.193, issue.1, pp.92-101, 2007.
DOI : 10.1177/147470490700500109

A. Gallup, Why do we yawn? Primitive versus derived features, Neuroscience & Biobehavioral Reviews, vol.35, issue.3, pp.765-769, 2011.
DOI : 10.1016/j.neubiorev.2010.09.009

A. Gallup, G. Gallup, and . Jr, Yawning and thermoregulation, Physiology & Behavior, vol.95, issue.1-2, pp.10-16, 2008.
DOI : 10.1016/j.physbeh.2008.05.003

A. Gallup, M. Miller, and A. Clark, Yawning and thermoregulation in budgerigars, Melopsittacus undulatus, Animal Behaviour, vol.77, issue.1, pp.109-113, 2009.
DOI : 10.1016/j.anbehav.2008.09.014

A. Gallup, L. Swartwood, J. Militello, and S. Sackett, Experimental evidence of contagious yawning in budgerigars (Melopsittacus undulatus), Animal Cognition, vol.82, issue.5, pp.1051-1158, 2015.
DOI : 10.1007/s10071-015-0873-1

G. Gessa, L. Vargiu, and W. Ferrari, Stretchings and Yawnings induced by Adrenocorticotrophic Hormone, Nature, vol.196, issue.5047, pp.426-427, 1966.
DOI : 10.1007/BF02150434

M. Greco, R. Baenninger, and J. Govern, On the context of yawning: when, where, and why?, Psych Rec, vol.43, pp.175-183, 1993.

A. Guggisberg, J. Mathis, A. Schnider, and C. Hess, Why do we yawn?, Neuroscience & Biobehavioral Reviews, vol.34, issue.8, pp.1267-1276, 2010.
DOI : 10.1016/j.neubiorev.2010.03.008

J. Hadidian, Yawning in an Old World Monkey, Macaca Nigra (Primates: Cercopithecidae), Behaviour, vol.75, issue.3, pp.133-147, 1980.
DOI : 10.1163/156853980X00375

K. Hall, Behaviour of Monkeys Towards Mirror-Images, Nature, vol.15, issue.4861, pp.1258-1261, 1962.
DOI : 10.1038/1961258a0

M. Hausberger, C. Bruderer, L. Scolan, N. Pierre, and J. , Interplay Between Environmental and Genetic Factors in Temperament/Personality Traits in Horses (Equus caballus)., Journal of Comparative Psychology, vol.118, issue.4, pp.434-446, 2004.
DOI : 10.1037/0735-7036.118.4.434
URL : https://hal.archives-ouvertes.fr/hal-01319156

M. Hausberger, C. Fureix, M. Bourjade, S. Wessel-robert, and M. Richard-yris, On the significance of adult play: what does social play tell us about adult horse welfare?, Naturwissenschaften, vol.43, issue.5, pp.291-302, 2012.
DOI : 10.1007/s00114-012-0902-8
URL : https://hal.archives-ouvertes.fr/hal-01021858

R. Hinde and T. Rowell, COMMUNICATION BY POSTURES AND FACIAL EXPRESSIONS IN THE RHESUS MONKEY (MACACA MULATTA), Proceedings of the Zoological Society of London, vol.188, issue.5, pp.1-21, 1962.
DOI : 10.1111/j.1469-7998.1962.tb05684.x

B. Holmgren, R. Urbá-holmgren, M. Aguiar, and R. Rodrigez, Sex hormone influences on yawning behavior, Acta Naurobiol, vol.40, pp.515-519, 1980.

R. Joly-mascheroni, A. Senju, and A. Sheperd, Dogs catch human yawns, Biology Letters, vol.9, issue.1, pp.446-448, 2008.
DOI : 10.1007/s10071-005-0257-z

C. Lesimple, C. Fureix, H. Menguy, and M. Hausberger, Human direct actions may alter animal welfare, a study on horses (Equus caballus), PLoS One, vol.5, 2010.
URL : https://hal.archives-ouvertes.fr/hal-01019964

P. Leyhausen, . Je, H. Bornett-gauci, and R. Wilkinson, Cat behaviour. The predatory and social behaviour of domestic and wild cats Horse personality: variation between breeds, Appl Anim Behav Sci, vol.112, pp.369-383, 1979.

D. Maestripieri, G. Schino, F. Aureli, and P. Troisi, A modest proposal: displacement activities as an indicator of emotions in primates, Animal Behaviour, vol.44, issue.5, pp.967-979, 1992.
DOI : 10.1016/S0003-3472(05)80592-5

P. Martin, P. Bateson, . Pj, N. French, L. Green et al., Measuring behaviour: an introductory guide Management factors associated with stereotypic and redirected behaviour in the thoroughbred horse, Equine Vet J, vol.27, pp.86-91, 1995.

S. Mcdonnell and J. Haviland, Agonistic ethogram of the equid bachelor band, Applied Animal Behaviour Science, vol.43, issue.3, pp.147-188, 1995.
DOI : 10.1016/0168-1591(94)00550-X

M. Mendl, O. Burman, and E. Paul, An integrative and functional framework for the study of animal emotion and mood, Proceedings of the Royal Society B: Biological Sciences, vol.35, issue.4, pp.2895-2904, 2010.
DOI : 10.1111/1467-9280.00157

A. Moyaho, J. Eguibar, and J. Diaz, Induced grooming transitions and open field behaviour differ in high-and, 1995.

S. Peters, E. Bleijenberg, M. Van-dierendonck, J. Van-der-harst, and B. Spruijt, Characterization of anticipatory behaviour in domesticated horses (Equus caballus), Applied Animal Behaviour Science, vol.138, issue.1-2, pp.60-69, 2012.
DOI : 10.1016/j.applanim.2012.01.018

E. Price, Behavioral development in animals undergoing domestication, Applied Animal Behaviour Science, vol.65, issue.3, pp.245-271, 1999.
DOI : 10.1016/S0168-1591(99)00087-8

G. Serra, M. Collu, A. Serra, and G. Gessa, Estrogens antagonize apomorphine-induced yawning in rats, European Journal of Pharmacology, vol.104, issue.3-4, pp.383-386, 1984.
DOI : 10.1016/0014-2999(84)90418-7

E. Smith, Yawning: An evolutionary perspective, Human Evolution, vol.122, issue.8585, pp.191-198, 1999.
DOI : 10.1007/BF02440156

N. Tinbergen, "Derived" Activities; Their Causation, Biological Significance, Origin, and Emancipation During Evolution, The Quarterly Review of Biology, vol.27, issue.1, pp.1-32, 1952.
DOI : 10.1086/398642

A. Troisi, Displacement Activities as a Behavioral Measure of Stress in Nonhuman Primates and Human Subjects, Stress, vol.5, issue.1, pp.47-54, 2002.
DOI : 10.1080/102538902900012378

A. Troisi, F. Aureli, G. Schino, F. Rinaldi, D. Angelis et al., The Influence of Age, Sex, and Rank on Yawning Behavior in Two Species of Macaques (Macaca fascicularis and M. fuscata), Ethology, vol.10, issue.4, pp.303-310, 1990.
DOI : 10.1111/j.1439-0310.1990.tb00437.x

R. Urbá-holmgren, N. Trucios, B. Holmgren, J. Eguibar, A. Gavito et al., Genotypic dependency of spontaneous yawning frequency in the rat, Behavioural Brain Research, vol.40, issue.1, pp.29-35, 1990.
DOI : 10.1016/0166-4328(90)90039-H

O. Walusinski and B. Deputte, Le b??illement : phylogen??se, ??thologie, nosog??nie, Revue Neurologique, vol.160, issue.11, pp.1011-1021, 2004.
DOI : 10.1016/S0035-3787(04)71138-8

G. Waring, Horse behavior, 2003.