Equine Social Behaviour: Love, War and Tolerance
Abstract
:Simple Summary
Abstract
1. Introduction
2. Materials and Methods
2.1. Data Sources and Searches
2.2. Data Extraction and Risk of Bias Assessment
3. Results
3.1. Study Selection
3.2. Quality and Risk of Bias Assessment
3.3. Data Synthesis
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Author(s), Publication Year | Study Design | Control Group | Observation Method(s) | Observation Duration | Observation Time Window | Number of Incl. Behaviours |
---|---|---|---|---|---|---|
Wells & Goldschmidt-Rothschild 1979 [5] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Random order, direct in the field, focal and scan sampling (15 min 3×/day per horse) | 16 weeks (4 × 3 blocks, 1 × 4-week block) | 7:00–19:00 | 8 |
Arnold & Grassia 1982 [88] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Random order, direct in the field, focal sampling (4 h/day) | Between October and December | 2 h in the morning and 2 h in the afternoon | 2 |
Wood-Gush & Galbraith 1987 [89] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Random order, direct in the field, focal and scan sampling (1×/h or 1×/15 min all positions + 15 min continuously of activity and social interaction) | 11.5 weeks (36 h) | 8:30–16:30 | 10 |
Feh 1988 [79] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Direct in the field, focal and scan sampling (1×/10 min/horse all positions) | 4 h/day, 5 weeks | 8:00–19:00 | 17 |
Keiper 1988 [91] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Random order, direct in the field, focal sampling (15 min/horse) | 2 months, 44.5 h in total | 4–5 h, between 9:00 and 16:00 | 9 |
Kolter & Zimmermann 1988 [90] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Random order, direct in the field, all occurrence sampling technique | 113 h in total, throughout the year | 2 h in the morning + 2 h in the afternoon | 16 |
Ellard & Crowell-Davis 1989 [29] | Experimental study—Pre-post study design. Randomized pairs for testing | Absent. No randomization for group constitution | Direct in the field, all occurrence sampling techniques and scan sampling (nearest neighbour every 15 min) | 56.7 h in total (2 h/day, 5 d/week, 6 weeks) | 15.00–17.00 | 9 |
Keiper & Receveur 1992 [55] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Direct in the field, all occurrence sampling techniques | 159 h in total (4.5 h/day, 41 days) | 4 or 5 h, between 5:00 and 24:00 | 16 |
McDonnell & Haviland 1995 [37] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Direct in the field, ad libitum sampling technique | 50 h in total, 4 weeks | daylight hours | 23 |
Christensen et al., 2002 (a) [12] | Experimental study—Randomized controlled trial study design | Horses randomly assigned, individual vs. group stabling | Direct in the field, focal sampling (social interaction: 3 h/day/group) and scan sampling (nearest neighbours: every 10 min for 1 h, 4 days/week) | 192 h in total, 28 h/week for 6 weeks | 3 h, 6:00 and 22:00 | 14 |
Christensen et al., 2002 (b) [13] | Observational study (field)-ecological study design | Comparison between two non-randomized groups, no interventions | Direct in the field, focal sampling (social interaction: 3–4 h/day/group) and scan sampling (nearest neighbour: every 10 min) | 72 h/group | 3 or 4 h windows during daylight hours | 14 |
Snorrason et al., 2003 [22] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Random order, focal sampling (social interaction: 15 min) and scan sampling (nearest neighbour: every 30 min) | 488 h in total, 5 weeks | throughout 24 h | 11 |
Heitor et al., 2006a (part I) [14] | Observational study (field)-ecological study design | Absent. No randomization for group constitution. | Random order, direct in field, focal sampling for social interactions, scan sampling every 5 min for activity and nearest neighbour | 386 h, 80.4 h per mare (range 74.9–88.1) and 54.5 h for the stallion | between 07:30 and 16:30 h | 14 |
Heitor et al., 2006b (part II) [30] | 14 | |||||
Jørgensen et al., 2009 [54] | Observational study (farm)-ecological study design | Comparison between three groups with non-randomized composition, no interventions | Direct in the field, focal sampling for social interactions (2 h/day for 3 days, 4 horses/group), scan sampling for nearest neighbour every 10 min | 6 h/group | between 8:00–11:00 and 12:00–15:00 | 18 |
Zharkikh & Andersen 2009 [92] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Random order, direct in the field, focal sampling (15 min, 3×/horse/day) and scan sampling for nearest neighbour every 10 min | 216 h, 18 days | between 6:00 and 18:00 | 22 |
Heitor & Vicente 2010 [26] | Observational study (farm)-ecological study design | Absent. No randomization for group constitution | Random order, direct in the field, focal sampling (social interaction: 25 min/horse/day) scan sampling for nearest neighbour every 5 min and ad libitum | 141 h in total, 5 months | between 6:30 and 18:30 | 15 |
Christensen et al., 2011 [58] | Experimental study-Randomized controlled trial study design | Horses were randomly assigned, stable group vs. unstable group | Direct in the field, focal sampling (2 × 20 min/group/day) | 3 months per year for 2 years | between 8.00–11:00 and 12:00–15:00 | 16 |
Schneider & Krueger 2012 [34] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Direct in the field, ad libidum sampling of third-party interventions and scan sampling (1×/h group spatial map) | 44 h over three months (non-consecutive) | daylight hours (max. 6.5 h/day) | 11 |
Flauger & Krueger 2013 [80] | Experimental study—Pre-post study design | Absent. No randomization. Groups measured before and after intervention (change of paddock size) | Focal sampling (4 h/group) and focal sampling (introduction of new horses (2 h/introduction) | variable number of observations between groups (average 6 times, range 1 to 13) | NA | 7 |
Freymond et al., 2013 [56] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Behaviour sampling of social interactions | 23 days: 109 h/horse, 17 days: 87 h/horse | either 9–11; 13–15; 17–18 or 7–9; 11–13; 15–17 | 14 |
Krueger et al., 2014 [41] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Direct in the field, ad libidum sampling (social interaction: 14 h/group) and scan sampling (spatial organization: map drawn 1×/h for 15 h/group | May 2009 and May 2010 | daylight hours (max 6.5 h/day) | 12 |
Krueger et al., 2015 [52] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Direct in the field, ad libidum sampling (social interaction: 9 × 4 h) and focal sampling (newly introduced horse 4 × 2 h/horse) | between April 2008 and May 2010 | for 4 h approximatively, daylight hours | 11 |
Górecka-Bruzda et al., 2016 [93] | Observational study (field)-ecological study design | Comparison between two groups with non-randomized composition with no interventions | Przewalski: twice/day during 5 time slots, 10 min/focal horse, 10 h/horse in total Domestic horses: 3 time slots, 5 min/focal horse, 4.16 h/horse in total | Przewalski horses: 10 h/horse; Domestic horses: 4.16 h/horse | Przewalski: daylight hours (7:00–21:00); Domestic Horses: daylight hours (6:00–19:30) | 9 |
Majecka & Klawe 2017 [94] | Experimental study—Pre-post study design | Absent. No randomization. Measurements before and after intervention (=change of paddock size) | Direct in the field, focal sampling (social interaction, 30 min once or twice/group/day) | between March and July 2011, 43 × 30 min | 9 a.m.–12 p.m. | 13 |
Wolter et al., 2018 [27] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Direct in the field, continuous ad libitum sampling (social interaction) and scan sampling (spatial proximity every 10 min) | 165 h in total | daylight hours | 9 |
Pierard et al., 2019 [62] | Observational study (field)-ecological study design | Absent. No randomization for group constitution | Direct in the field, all occurrence sampling (social interaction: 90–120 min, 2–4×/day) and scan sampling (spatial position every 15 min) | 17 days; 54 h 25 min | not fixed | 12 |
Author(s), Publication Year | Total Horses (n) | Number of Herds | Horses/Herd | Type and Breed | Sex | Age (Years) Mean +/− s.d. (Range) | Size of Enclosure | Feeding |
---|---|---|---|---|---|---|---|---|
Wells & Goldschmidt-Rothschild 1979 [5] | 18 | 1 | 18 | semi-feral (Camargue) | 8 mares, 2 stallions, 22-year-old stallions, 6 yearlings, 7 foals | NA | 300 ha | NA |
Arnold & Grassia 1982 [88] | study 1: 17; study 2: 12 | 1 | study 1: 17; study 2: 12 | domesticated (NA) | study1: 16 mares/1 male; study 2: 11 mares/1 male | study 1: 10.3 +/− 7 (3–24); study2: 19.6 +/− 7.5 (4–32) | 12 ha, 15 ha | chaff, grains, hay |
Wood-Gush & Galbraith 1987 [89] | 13 | 1 | 13 | domesticated (Exmoor, Highland) | 2 mares, 11 males | 14 +/− 5.2 (6–22; one NA) | 2 ha | daily hay |
Feh 1988 [79] | 9 | 2 | 4; 5 | semi-feral (Przewalski) | 4 mares, 5 males | 3 +/− 1.2 (2–5) | 4 ha, 16 ha | grass, hay, pellets |
Keiper 1988 [91] | 6 | 1 | 6 | semi-feral (Przewalski) | 5 mares, 1 male, 3 foals | 8 +/− 8.9 (0–21) | NA | NA |
Kolter & Zimmermann 1988 [90] | 7 | 1 | 7 | semi-feral (Przewalski) | 6 mares, 1 male | 9.75 +/− 7.5 (1–22) | 2800 m2 | hay, oats, pellets |
Ellard & Crowell-Davis 1989 [29] | 12 | 1 | 12 | domesticated (Belgian, Percheron) | 12 mares | 6.9 +/− 3.6 (2–13) | 10 ha | daily hay |
Keiper & Receveur 1992 [55] | 10 | 2 | 5; 5 | semi-feral (Przewalski) | 6 mares, 4 stallions | 3 +/− 2.8 (0–8) | 37 ha, 350 ha | grass, hay, pellets |
McDonnell & Haviland 1995 [37] | 15 | 1 | 15 | domesticated (NA) | 15 stallions | (2–21) | 2 acres | NA |
Christensen et al., 2002 (a) [12] | 19 | 2 | 12; 7 | domesticated (Danish Warmblood) | 19 stallions | 2 years old | group 1: 5.6 × 4.8 m boxes + 40 × 90 m paddocks; group 2: 3.6 × 2.5 m boxes + 20 × 40 m paddocks; 2 ha/group; 4 ha | barley straw, concentrate, grass, hay, molasses, silage |
Christensen et al., 2002 (b) [13] | 32 | 1; 1 | 19; 13 | domesticated (NA); semi-feral (Przewalski) | 32 stallions | group 1: 2; group 2: 5.2 +/− 3.3 (2–13) | 4 ha, 75 ha | grass |
Snorrason et al., 2003 [22] | 33 | 1 | 33 | domesticated (Icelandic) | 17 mares, 2 geldings, 14 yearlings and 8 foals (sex not specified) | 9 +/− 6.7 (1–20) | 8 ha | grass, silage |
Heitor et al., 2006a (part I) [14] | 11 | 1 | 11 | domesticated (Sorraia) | 10 mares, 1 stallion | 11 +/− 3.6 (5–18) | 5.5 ha, 17.2 ha | grass, hay |
Heitor et al., 2006b (part II) [30] | 11 | 1 | 11 | domesticated (Sorraia) | 10 mares, 1 stallion | 11 +/− 3.6 (5–18) | 5.5 ha, 17.2 ha | grass, hay |
Jørgensen et al., 2009 [54] | 66 | 3 × 6 rounds | 3; 3; 4; 4; 5; 3; 3; 3; 4; 4; 6; 4; 4; 4; 4; 5; 9; 3 | domesticated (Warmblood, Norwegian Fjord) | 22 mares, 24 males. Composition of one group unspecified | (1–26) | from 100 to 75,000 m2/horse | grass, roughage |
Zharkikh & Andersen 2009 [92] | 16 | 1 | 16 | semi-feral (Przewalski) | 16 males | (5–16) | 3.5 ha | grass |
Heitor & Vicente 2010 [26] | 11 | 1 | 11 | domesticated (Sorraia) | 11 mares | (4–22) | 5.5 ha, 17.2 ha | grass, hay |
Christensen et al., 2011 [58] | 45 | 15 | 3 | domesticated (Danish Warmblood) | 45 mares | 2-years-old | 80 × 80 m | barley, barley straw, grass, seed cake and minerals, silage |
Schneider & Krueger 2012 [34] | 84 | 4 | 14; 20; 30; 20 | feral (Espéra ponies) | group 1: 13 mares/1 stallion; group 2: 19 mares/1 stallion; group 3: 27 mares/3 stallions; group 4: 19 mares/1 stallion | (1–28) | free-ranging | mountain pastures |
Flauger & Krueger 2013 [80] | 68 | 11 | 3; 4; 3; 8; 14; 3; 3; 15; 4; 8; 3 | domesticated (Warmblood, Quarter horses, Trotters, Haflingers, ponies) | NA | (1–30) | 402 m2, 17,882 m2 | NA |
Freymond et al., 2013 [56] | 9 | 2 | 5; 9 (four were included in both groups) | domesticated (Franches-Montagnes) | 9 stallions | (8–19) | 4 ha | hay |
Krueger et al., 2014 [41] | 55 | 3 | 11; 19; 25 | feral (Espéra ponies) | group 1: 10 mares/1 stallion; group 2: 18 mares/1 stallion; group 3: 22 mares/3 stallions | (1–23) | free-ranging | hay |
Krueger et al., 2015 [52] | 11 | 1 | 11 | semi-feral (Przewalski) | 11 stallions | (2–8) | 50 ha | hay, horse feed |
Górecka-Bruzda et al., 2016 [93] | 27 | 2; 4 | 4–6, 4–6; 5, 2, 8, 4 | semi-feral; domesticated | semi-feral groups: 4–6 adult males; domestic group 1: 2 males + 3 geldings; group 2: 2 males; group 3: 1 male + 7 females; group 4: 1 male + 3 females | NA | from 2 to 1600 ha | hay |
Majecka & Klawe 2017 [94] | 78 | 3 | 26; 28; 24 | domesticated (Friesian, Arabian, Shetland, Warmblood) | 41 mares, 25 geldings, 12 stallions | group 1: 10.2 (2–21); group 2: 8.8 (2 months-30 years); group 3: 5.3 (3 months-16 years) | from 0.35 to 8.1 ha | hay |
Wolter et al., 2018 [27] | 145 | 11 | 5; 7; 6; 9; 9; 23; 10; 12; 19; 26; 19 | semi-feral (Przewalski)—feral (Equus ferus caballus) | 113 mares, 32 males | group 1: 2.6; group 2: 8.7; group 3: 8.5; group 4: 6.2; group 5: 10.4; NA for other groups | free-ranging | hay |
Pierard et al., 2019 [62] | 11 | 1 | 11 | domesticated (Irish Cob, Arabian, Warmblood) | 10 mares, 1 gelding | 10 +/− 7.3 (1–29) | from 160 m2 to 610 m2 | hay |
Social Behaviour Category | Social Behaviour | Definition | Differences in the Definition | Used by n/27 Papers | Comments |
---|---|---|---|---|---|
Approach eliciting retreat [12,13,14,26,27,29,34,37,41,52,55,58,91,92]/Displacement [54] | Approach of one horse with ears back causes another to move away so that distance is maintained or increased | “Approach within 2 m distance” [29]/two body-length distance14 | 15 | Displacement is used variably either to describe “eliciting retreat” or “supplant”; to minimize ambiguity, we propose avoiding “displace” and differentiate the two types of agonistic approach as approach-retreat and approach-supplant | |
agonistic–aggressive | (Approach with) Supplantation [29,79]/Displacement [64] | Horse moving toward another horse and taking the exact same place after the other horse moved away | Either individual may have laid back ears [29] | 3 | |
Arched neck threat [37] | Neck tightly flexed with the muzzle drawn toward the chest; observed during close aggressive encounters and ritualized interactions | 1 | |||
Attack [14,22,26,30,90]/Lunge [37,56] | Fast movement toward another horse, with ears flattened, head stretched horizontal | “One horse rears with the forelegs in the direction of another horse, ears laid back” [56] | 7 | ||
Backing [54] | Backward movement towards another horse with ears oriented backwards | 1 | |||
Bite [5,12,13,14,22,26,27,29,30,34,37,41,52,54,55,56,58,64,79,80,88,89,90,91,92,93,94] | Ears are laid back and teeth are closed on some body part of another animal. Lips retracted and contact is made with the target horse | 27 | Bite is considered as a grasp if the hold is maintained | ||
Bite threat [5,12,13,14,22,26,27,29,30,34,37,41,52,54,55,56,58,64,80,88,89,90,91,92,93,94] | Ears are laid back, the mouth is opened, and a biting motion is made while head or full body motion toward another animal, no contact is made. A bite intention movement and neck extended | 26 | |||
Chase [14,22,26,27,29,30,34,37,41,52,54,55,56,58,64,80,90,91,92,93,94] | With its ears pinned back, the aggressor chases another individual | Specification of “for at least 1” [29] or “3 [64] strides”; “at a gallop“ [92]; “The movement can be either at a walk, trot or gallop” [80] | 21 | We propose limiting “chase” to fast gaits to differentiate between “agonistic approach” and “chase” | |
Circling [37,56] | Two horses circle each other head-to-tail, trying to nip or bite each other’s body parts | 2 | Can also be part of play behaviour | ||
Fight [92] | High-level prolonged mutual aggression involves bites, strikes, kicks, chase, etc. Usually, the opponents squeal | 1 | |||
Head bump [37] | A rapid lateral toss of the head that forcefully contacts the head and neck of another horse. Usually, the eyes remain closed and the ears forward | 1 | |||
Head-threat [5,29,37,54,64,79,90,94] | The extension of the aggressor’s head and neck towards another individual while laying the ears against its head | 8 | |||
Herding [14,26,30,37,41,55,90,91]/Driving [5]/Snaking [92] | Combination of head threat with the ears back and forward locomotion directing the movement of another horse | Swinging head sideways [14,91,92] | 10 | ||
Kick [12,13,14,22,26,27,29,30,34,37,41,52,54,55,56,58,64,79,80,88,89,90,91,92,93,94] | With its ears laid back, one or both hindlegs of the aggressor are extended backwards rapidly and strike another animal with apparent intent to make contact | 26 | |||
Kick-threat [5,12,13,14,22,26,27,29,30,34,37,41,52,54,55,56,58,64,79,80,88,89,90,91,92,93,94] | The aggressor, with its ears laid back, either (1) makes a rapid movement to place its hindquarters near another animal; or (2) raises a hind limb to potentially strike another; or (3) kicks with 1 or both hindlimbs towards another animal, but no contact is made | Vigorous tail switching, production of a harsh squeal [37,93] | 27 | ||
Mild threat [14,26,30] | Ears laid back and looking or walking towards another horse | 3 | Definition lacks details; combined with movement analogous to an agonistic approach | ||
Push [12,13,37,54,56,58,89,92,94] | Pressing of the head, neck, shoulder, body, or croup against another in an apparent attempt to displace the target animal | 9 | |||
Strike [37,54,55,56,58,64,91,92] | A rapid motion of one or both forelegs in the anterior direction | Arched neck threat and posturing [37,58] | 8 | ||
Strike-threat [37,64] | The aggressor’s ears are laid back, and its head and shoulders are oriented toward another individual. One or both forelimbs move out- and forward toward the other animal, but no contact is made | 2 | |||
Agonistic submissive | Avoidance/Withdrawal [14,22,26,30,37,64,90,92] | Movement that maintains or increases the distance to an approaching horse (which does not threaten). While making way, the subordinate usually lays its ears back | Only head turn away from the initiator [14,30] | 8 | These three terms are used interchangeably → clarification of the definitions is required. We propose using avoidance/withdrawal to indicate increase/maintenance of distance to a non-threatening approaching horse, retreat as a reaction to an agonistic approach at the walk or trot, and flight as a rapid increase/maintenance of distance in response to an attack |
Retreat [27,34,37,41,52,80] | One individual immediately moves away from an animal that approaches to within 2 m of it to maintain or increase the distance | 6 | |||
Flight [22,56] | Avoiding, retreating from another horse, usually with ears laid back | Walking, trotting or galloping [56] | 2 | ||
Balk [37] | Abrupt halt or reversal of direction with movement of the head and neck in a rapid sweeping dorsolateral motion away from an apparent threat while the hind legs remain stationary. The forelegs may simultaneously lift off the ground | 1 | |||
Snapping [5,12,13,22,37,54,55,58,79] | Corners of the open mouth are pulled back, showing teeth and gums, making chewing motions. Hindlegs may be slightly bent in a cringing position. Head and neck are extended, the ears are oriented back or laterally | An appeasement act delivered to older/higher-ranked animals [55] | 9 | ||
affiliative | (Affiliative) Approach [5,14,27,30,55,64,80,90,93] | Moving to within 1 m [5]/1 [27]/2 [14,26,30] body-lengths of another horse that does not immediately move away and staying there for at least 5 [64]/10 [14,26,30] s without agonistic interaction | Across one [27]/two [14,26,30] body-length distance | 9 | |
Grooming approach [34,41,52] | Approach with subsequent mutual grooming | 3 | |||
Mutual approach [34,41,52] | Both animals approach each other | 3 | |||
Following [14,26,30,37,55,56,79,90] | Moving immediately behind another horse that had just initiated locomotion and stay within three body-lengths for at least 10 s without agonistic interaction and without initiating physical contact | Head low without any attempt to attack or bite [56] | 8 | ||
Friendly body contact/Touching [5,14,26,30,55,79,89,92] | Touch made with ears forward or laterally positioned | Lightly with the nose or lips, also called nose-body contact [55,79,89] | 8 | ||
Head contact [37,54,58,79,90,92,93] | A position where a horse puts its chin on the back or rear of a companion | 7 | |||
Mutual grooming [5,12,13,14,22,26,27,30,34,37,41,52,54,55,56,58,64,79,88,89,90,91,92,93,94] | Two horses stand head to tail and chew or nuzzle each other’s coats | After introductory sniffing [93], by gently nipping, nuzzling or rubbing [27,37,54,56,64,95] | 25 | ||
Pairing/Stand resting together [26,90] | Standing together (in antiparallel position), less than 0.5–1 m apart | 2 | |||
Pass the mane/Under the neck [92] | A horse passes (its mane) under its companion’s chin and neck. The other horse may or may not reciprocate | 1 | |||
Play [5,12,13,22,54,55,56,58,79,89,90,92,94] | Play includes playful nips, pounces, etc. A playful character of the interaction is indicated by the ears oriented forward or laterally, lips protruded, and teeth covered. Vocalization (squeal or scream) is not produced | 13 | |||
Play fight [12,13,54,58,94] | High-intensity play, which is reciprocated by one or more partners, includes vigorous play movements such as rearing, boxing, nipping, circling, grasping, kneeling and chasing | 5 | |||
Rubbing with the head/chin/body [79,92] | Rubbing up and down with the forehead/cheek/chin/itself against a companion | 2 | |||
investigative | Head bowing [37,92] | Repeated, exaggerated, rhythmic flexing of the neck such that the muzzle is brought toward the point of the breast. Usually occurs synchronously between two horses when they first approach each other head to head | A squeal is emitted [92] | 2 | These behaviours can be investigative or agonistic depending on whether or not they are followed by squeals and stomping |
Nose-nose interaction [55,79,89,92] | Two horses approach each other with arched necks and touch noses standing either opposite each other or side by side | Squeal always follows, and a stomp almost always occurs [92] | 4 | ||
Olfactory investigation (nasal/genital/body sniff) [12,13,37,54,56,58,79,90,91,92,93,94] | Sniffing various parts of another horse’s body, including the head, neck, flank, genitals, and tail or perineal region. Another horse may or may not reciprocate | Squeal produced during the behavioural ritual “sniff and squeal” [56] | 11 | ||
neutral | Neutral approach [34,41,52,79] | One animal approaching another without subsequent agonistic or affiliative interactions | 4 |
Quantitative Assessment | Formula | Reference | |
---|---|---|---|
Frequency of Behaviours | Social interactions | Total number of affiliative and agonistic behaviours observed/per horse and or per hour | [12,13,14,34,55,56,64,80,89,92,93,94] |
Mean number of social interactions per week | [58] | ||
Social interactions in %: (Number of observations of a behaviour/total number of observed behaviours) × 100 | [5,54,55] | ||
Aggressiveness, aggressive score | Total number of agonistic behaviours observed | [27,29,79,90] | |
Count of agonistic acts received and given | [55] | ||
Aggression rate per group per horse/total number of aggressions per group per horse | [27] | ||
Activity similarity | (Number of observations including A and B)/(Total number of observations of A + total number of observations of B) | [22,89] | |
Time percentage when two horses were first neighbours and engaged in the same activity | [5] | ||
Nearest neighbour | Nearest neighbour per activity = Time that individuals were first neighbour to each other when engaged in same activity/time that individuals were first neighbour to each other × 100 | [5,89] | |
Frequency of two individuals being observed as “being close” or “being far” | [79] | ||
Number of observations including A and B/total number of observations of A + total number of observations of B | [89,92] | ||
Observations of an individual at a specific distance/Total observations of that individual at any distance × 100 | [22,54] | ||
Total number of observations in which an individual was either the first or second neighbour of a particular one (single link cluster analyses) | [5] | ||
Duration | Duration of a behaviour/interaction | Time in seconds from start to end | [37,90] |
Dominance Relationships | Ranking index | Number of agonistic encounters won by A against B/total number of agonistic encounters in which A and B were involved | [27,29,34,52,55,90,92] |
Highest rank = individual with least threats possible from individuals below it | [5,55] | ||
Comparison between the number of threats received by individuals and the number of threats initiated | [22,91] | ||
[(Number of horses that this male dominates—number of horses that this male is dominated by + group size + 1)/2] | [56] |
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Torres Borda, L.; Auer, U.; Jenner, F. Equine Social Behaviour: Love, War and Tolerance. Animals 2023, 13, 1473. https://doi.org/10.3390/ani13091473
Torres Borda L, Auer U, Jenner F. Equine Social Behaviour: Love, War and Tolerance. Animals. 2023; 13(9):1473. https://doi.org/10.3390/ani13091473
Chicago/Turabian StyleTorres Borda, Laura, Ulrike Auer, and Florien Jenner. 2023. "Equine Social Behaviour: Love, War and Tolerance" Animals 13, no. 9: 1473. https://doi.org/10.3390/ani13091473