{ "meta": { "slug": "the-conditional-horse", "compiled": "2026-09-16", "note": "Every empirical number this page shows a reader lives here, with the source it came from and how far the published range actually runs. The page reads this file; so does research/the-conditional-horse/verify.mjs. Nothing is typed twice. A figure still marked provisional fails the check, which is how a placeholder cannot reach a reader.", "tiers": { "established": "replicated, or measured by more than one group, and not in dispute", "contested": "the literature genuinely disagrees, and both sides are named", "thin": "one study, a small sample, or a figure everyone repeats whose origin is not traceable", "derived": "not measured at all: worked out here from other published figures, and marked as such on the page" }, "equidRows": 8 }, "figures": { "hoof.growth": { "low": 0.19, "typical": 0.25, "high": 0.384, "unit": "mm/day at the toe", "tier": "established", "source": "Josseck H, Zenker W, Geyer H (1995), Equine Vet J 27:175-182, doi:10.1111/j.2042-3306.1995.tb03060.x, 42 Lipizzaner stallions, verbatim: 'Growth rate of the horn wall was equal in the biotin and placebo group, being 7 mm/28 days, giving a wall renewal period of 11 months.' High end: Butler KD & Hintz HF (1977), J Anim Sci 44:257-261, doi:10.2527/jas1977.442257x, 0.384 mm/day on ad libitum feed. Low end: Malone SR & Davies HMS (2019), Animals 9:1017, shod forelimbs at 0.191 to 0.197 mm/day.", "note": "The range given here is from primaries this page read. A lower anchor of 0.18 mm/day circulates, attributed to Reilly and colleagues 1998; the audit could not find that daily rate stated anywhere in that paper's own abstract, only in a later paper's citation of it, so it is not used." }, "hoof.growthRestricted": { "typical": 0.254, "unit": "mm/day at the toe", "tier": "established", "source": "Butler KD & Hintz HF (1977), J Anim Sci 44:257-261, doi:10.2527/jas1977.442257x, verbatim: 'Ponies fed the diet ad libitum consumed 180% more feed, had 50% greater rate of hoof growth (.384 +/- .009 vs .254 +/- .008 mm/d)'.", "note": "The same ponies on restricted feed. The feed bucket moves hoof growth by half." }, "hoof.wear": { "low": 0.059, "typical": 0.169, "high": 0.52, "unit": "mm/day at the toe", "tier": "thin", "source": "Malone SR & Davies HMS (2019), Animals 9:1017, doi:10.3390/ani9121017, 11 Quarter Horse mares on sand: 0.059 mm/day shod and 0.169 barefoot over 49 days, the only directly measured daily wear rates this page found. The upper end comes from Florence L & McDonnell SM (2006), Equine Vet J 38:642-645, on semi-feral ponies, quoted through Malone & Davies as 'a mean of 0.24 +/- 0.03 mm to 0.52 +/- 0.04 mm'.", "note": "That quoted sentence carries NO TIME UNIT, in a paper that labels its other rates 'mean daily growth' explicitly. Reading it as a daily rate is an inference, and the page says so. There is also no published wear rate at all for a horse working on a road." }, "hoof.wallLength": { "typical": 78.1, "unit": "mm, dorsal wall length at the toe", "tier": "thin", "source": "Lesniak K et al. (2017), Table 5: dorsal hoof wall length 7.81 +/- 1.35 cm, from 17 measurements taken from photographs of 26 horses.", "note": "Measured, unlike the figure this page used first, which was derived by dividing Josseck's wall renewal period by their growth rate. The two agree to within eight per cent, which is some comfort.", "low": 64.6, "high": 91.6 }, "hoof.capsuleMonths": { "low": 7, "typical": 11, "high": 14, "unit": "months to replace the whole wall", "tier": "established", "source": "Josseck H, Zenker W, Geyer H (1995), Equine Vet J 27:175-182, verbatim: 'giving a wall renewal period of 11 months.' The range is what the published growth spread implies for a 78 mm wall: 78.1/0.384 = 203 days at the fast end, 78.1/0.19 = 411 days at the slow end.", "note": "The 'a year to grow a new hoof' rule of thumb is defensible and is a division, not a measurement. It moves by a factor of two across the published growth range." }, "hoof.cycleDays": { "low": 21, "typical": 42, "high": 120, "unit": "days between trims or resets", "tier": "thin", "source": "Six to eight weeks is farriery convention and this page found no measurement establishing it. What stretching it does has been measured: Moleman M, van Heel MC, van Weeren PR, Back W (2006), Equine Vet J 38:170-174, doi:10.2746/042516406776563242.", "note": "Convention, not a finding. The consequence of exceeding it is the finding." }, "hoof.trimThreshold": { "typical": 5, "unit": "mm of accumulated toe length", "tier": "derived", "source": "Derived: at the published surplus rates a foot gains roughly 3 to 6 mm at the toe over six weeks (Malone & Davies 2019 measured 6.8 mm over seven weeks in shod horses). 5 mm is the middle of that and is used here only to mark the chart.", "note": "A drawing aid, not a clinical threshold." }, "hoof.angleStart": { "typical": 55.4, "unit": "degrees, hoof angle at shoeing", "tier": "established", "source": "Moleman M et al. (2006), Equine Vet J 38:170-174, doi:10.2746/042516406776563242, 9 sound Warmbloods, radiographic hoof angle, start of an 8-week shoeing interval.", "note": "" }, "hoof.angleEnd": { "typical": 51.9, "unit": "degrees, hoof angle after 8 weeks", "tier": "established", "source": "Moleman M et al. (2006), same study, end of the interval. Their finding, verbatim: 'the moment about the PIPJ did not increase significantly, but the moment about the DIPJ did ... which leads to increased DIPJ extension and consequently an increased loading of the deep digital flexor tendon.'", "note": "" }, "hoof.loadPerFoot": { "typical": 0.6, "unit": "kg added at each foot", "tier": "established", "source": "Wickler SJ et al. (2004), Equine Vet J 36:772-777, doi:10.2746/0425164044848046, 6 horses, treadmill trot, 2.4 kg total distributed equally between four limbs at the level of the distal phalanx.", "note": "" }, "hoof.metabolicCost": { "typical": 6.7, "unit": "per cent increase in metabolic rate at trot", "tier": "established", "source": "Wickler SJ et al. (2004), Equine Vet J 36:772-777, verbatim: 'Loading of the distal limbs produced a 6.7% increase in metabolic rate, an order of magnitude higher than when the mass was added over the back.'", "note": "This is 0.6 kg per foot, not a horseshoe. Nobody has measured the oxygen cost of an actual set of shoes." }, "eye.panoramic": { "low": 310, "typical": 350, "high": 350, "unit": "degrees, total horizontal field", "tier": "thin", "source": "Miller PE & Murphy CJ, 'Equine Vision', in Gilger BC (ed.), Equine Ophthalmology, verbatim: 'The total horizontal visual field is up to 350 degrees'. This page could not trace that figure to a perimetry measurement in a horse; the chain runs through reviews to Hughes A (1977), a comparative book chapter.", "note": "Reconstructed from ocular anatomy, not measured by perimetry the way a human's field is." }, "eye.monocular": { "low": 190, "typical": 195, "high": 228, "unit": "degrees, one eye", "tier": "thin", "source": "Miller PE & Murphy CJ, Equine Ophthalmology, verbatim: 'A total monocular visual field in the horizontal meridian of approximately 190 to 195 degrees'. The 228 figure is from Rorvang MV, Nielsen BL, McLean AN (2020), Front Vet Sci 7:633, doi:10.3389/fvets.2020.00633, verbatim: 'the maximum extent of the uniocular field of view in the horse is 228 degrees with a mean around 195'.", "note": "" }, "eye.binocular": { "low": 55, "typical": 65, "high": 80, "unit": "degrees of overlap in front", "tier": "contested", "source": "Miller PE & Murphy CJ, verbatim: 'The visual fields of the two eyes overlap anteriorly and below the nose for 55 to 65 degrees, although some authors suggest the overlap may be as great as 70 to 80 degrees.' Roth LSV & McGreevy P (2025), Front Vet Sci 12:1647911, doi:10.3389/fvets.2025.1647911, give '65-80 degrees'.", "note": "Aimed down the nose, not straight ahead. Harman AM, Moore S, Hoskins R, Keller P (1999), Equine Vet J 31:384-390, doi:10.1111/j.2042-3306.1999.tb03837.x, verbatim: 'binocular overlap is oriented down the nose, with a blind area directly in front of the forehead.'" }, "eye.implied": { "typical": 325, "unit": "degrees, the total the other two figures imply", "tier": "derived", "source": "T = 2M - B with M = 195 and B = 65. The identity holds for any two laterally placed eyes and is checked in research/the-conditional-horse/verify.mjs.", "note": "" }, "eye.residual": { "typical": 25, "unit": "degrees the canonical set is short of itself", "tier": "derived", "source": "350 minus 325. Across the published variants of the three figures the gap runs from 15 to 40 degrees. No source this page found states the discrepancy or reconciles it.", "note": "The identity holds for two arcs in ONE plane. These three figures are hedged in their sources ('up to', 'approximately') and are drawn from different papers, and the overlap is described as anterior AND BELOW THE NOSE while the monocular figure is a horizontal meridian. So this is an arithmetic observation about a set of numbers that are printed together and are not commensurable as printed, rather than an error discovered in anybody's measurement. The finding that survives it intact is the one below: no published angle exists for the caudal blind wedge or the forehead blind area at all." }, "eye.monocularNeeded": { "typical": 207.5, "unit": "degrees of monocular field the published total would require", "tier": "derived", "source": "M = (T + B) / 2 with T = 350 and B = 65. Larger than any monocular figure this page found printed as a typical value.", "note": "" }, "eye.acuityStreak": { "typical": 16.5, "unit": "cycles per degree, visual streak", "tier": "established", "source": "Harman AM et al. (1999), Equine Vet J 31:384-390, verbatim: 'acuity in the narrow, intense visual streak in the inferior retina is 16.5 cycles per degree compared with 2.7 cycles per degree in the periphery.'", "note": "" }, "eye.acuityPeriphery": { "typical": 2.7, "unit": "cycles per degree, peripheral retina", "tier": "established", "source": "Harman AM et al. (1999), same sentence.", "note": "A sixfold gradient. It is why the ramp-retina story could not work." }, "eye.acuityBehavioural": { "typical": 23.3, "unit": "cycles per degree, best of three horses", "tier": "thin", "source": "Timney B & Keil K (1992), Vision Research 32:2289-2293, doi:10.1016/0042-6989(92)90092-W, verbatim: 'the best acuity obtained was 23.3 c deg-1'. n = 3 horses.", "note": "Three animals. Near the top of the handful of ungulates anyone has measured, and beaten by the giraffe at 25 to 27 cycles per degree by the same method, which is why this page does not call the horse the sharpest-eyed ungulate." }, "eye.starts": { "typical": 806764, "unit": "British flat starts analysed", "tier": "established", "source": "Rosanowski SM, Chang YM, Stirk AJ, Verheyen KLP (2018), PLoS ONE 13:e0194299, doi:10.1371/journal.pone.0194299, 2000 to 2013, 610 race-day fatalities.", "note": "" }, "eye.firstTimeOdds": { "typical": 1.83, "low": 1.25, "high": 2.69, "unit": "adjusted odds ratio, 95% CI", "tier": "established", "source": "Rosanowski SM et al. (2018), all-starts multivariable model: eye cover worn for the first time, adjusted OR 1.83 (95% CI 1.25 to 2.69), p < 0.001. Horses that had worn eye cover before: OR 1.18 (0.90 to 1.54), p = 0.23.", "note": "Observational, and fragile: the 1.83 rests on 28 deaths and the turf-only 2.08 on 21. Trainers fit first-time eye cover to horses already running badly, so confounding by indication is wide open, and the authors say the reason is unclear. A second and larger study disagrees with it: see eye.jumpOdds." }, "eye.maskEffective": { "typical": 3.8, "unit": "per cent of owners finding a light-blocking mask effective alone", "tier": "thin", "source": "Bell T, Kyriazopoulou P, Mowbray C, Murphy BA (2024), Animals 14:875, doi:10.3390/ani14060875, owner survey, 104 of 201 treated headshaking horses used light-blocking masks.", "note": "An owner survey, not a trial." }, "eye.maskIneffective": { "typical": 50.0, "unit": "per cent finding a light-blocking mask not effective", "tier": "thin", "source": "Bell T et al. (2024), same survey: 50.0% (n = 52) found them 'not effective'.", "note": "" }, "eye.noseNet": { "typical": 75, "unit": "per cent of owners reporting improvement with a nose net", "tier": "established", "source": "Mills DS & Taylor K (2003), Vet Rec 152:41-44, doi:10.1136/vr.152.2.41, 36 owners, within-subjects repeated measures, verbatim: 'Approximately 75 per cent of owners reported some overall improvement with each net'.", "note": "A device that covers no part of the eye outperforms the one that does." }, "sleep.total": { "low": 166.4, "typical": 230.72, "high": 262.1, "unit": "minutes of sleep per 24 h", "tier": "established", "source": "Greening L & McBride S (2022), Front Vet Sci 9:916737, a pooled review of equine polysomnography, verbatim: 'For horses, NREM sleep consistently accounts for the largest proportion of total sleep time (77.50%) (mean 178.74 +/- 87.53 min) compared to REM sleep (17.50% of total sleep time) (40.27 +/- 24.15 min).' The range ends are the individual studies pooled there.", "note": "Around a quarter of what a human sleeps, and the spread across studies is enormous." }, "sleep.remNeed": { "low": 22.5, "typical": 40.27, "high": 57.6, "unit": "minutes of paradoxical sleep per 24 h", "tier": "contested", "source": "Greening & McBride (2022) pooled mean 40.27 +/- 24.15 min. The range ends are the primary studies quoted by Burla J-B et al. (2017), Front Vet Sci 4:23, doi:10.3389/fvets.2017.00023: Kalus measured 22.5 to 37.2 min/night in seven horses, Dallaire reports 57.6 min/night in five individually stabled ponies.", "note": "Contested at the decimal, contested against the recumbency threshold, and contested at the definition. Kelemen Z et al. (2021), Animals 11:3189, cite the same body of work for a requirement of only 3.5 to 4.5 minutes, an order of magnitude lower. And horse sleep is staged with human criteria that were never validated in horses, criteria that include muscle atonia in the definition of the stage, which is part of why the stage is said to be impossible standing." }, "sleep.remBout": { "typical": 3.72, "unit": "minutes, one paradoxical sleep sequence", "tier": "established", "source": "Greening & McBride (2022), pooled mean REM sequence 3.72 min, range 0.91 to 5.13, with 10.5 sequences per night.", "note": "" }, "sleep.recumbentTypical": { "low": 0, "typical": 67.4, "high": 319, "unit": "minutes per 24 h spent lying down", "tier": "established", "source": "Kelemen Z, Grimm H, Long M, Auer U, Jenner F (2021), Animals 11:3189, doi:10.3390/ani11113189, 83 horses tracked by accelerometer over 131 tracking cycles: mean recumbency 67.4 +/- 61.9 min/day, range 0 to 319.", "note": "Thirteen of the 83 horses did not lie down at all, and stayed up for more than 72 hours." }, "sleep.recumbentThreshold": { "typical": 30, "unit": "minutes of recumbency per 24 h, the welfare threshold in use", "tier": "thin", "source": "Burla J-B et al. (2017), Front Vet Sci 4:23, verbatim: 'Derived from these findings, it can be assumed that horses need a minimal duration of recumbency of 30 min per 24 h to perform a minimal duration of REM sleep.'", "note": "Derived, not measured. No study has ever titrated recumbency against paradoxical-sleep sufficiency, and the same paper derives this threshold from measured paradoxical sleep durations of 22.5 to 57.6 minutes, which do not fit inside it." }, "sleep.occupancyAtThreshold": { "typical": 134, "unit": "per cent of lying time that would have to be paradoxical sleep", "tier": "derived", "source": "40.27 divided by 30. Computed in the page and asserted in research/the-conditional-horse/verify.mjs.", "note": "Over one hundred per cent is not a tight fit. It is impossible." }, "sleep.standingShare": { "typical": 75.6, "unit": "per cent of the 24 h day spent standing", "tier": "established", "source": "Kelemen Z et al. (2021), Animals 11:3189: standing 75.6% +/- 13.1 of the day, range 32.2 to 95.9.", "note": "" }, "sleep.noRecumbency": { "typical": 13, "unit": "of 83 tracked horses that did not lie down at all", "tier": "established", "source": "Kelemen Z et al. (2021): 13 horses showed no recumbency at all, all with chronic orthopaedic disease, and did not lie down for more than 72 hours.", "note": "" }, "sleep.stayApparatusSaving": { "typical": 98, "unit": "per cent mechanical saving in the hind limb from the stay apparatus", "tier": "thin", "source": "Schuurman SO, Kersten W, Weijs WA (2003), J Anat 202:355-362, doi:10.1046/j.1469-7580.2003.00166.x, on the authors' own calculation.", "note": "The same paper shows the lock is NOT passive: an isolated hind limb with the patella manually locked flexed immediately under small loads, and standing horses show continuous low-level vastus medialis activity. The apparatus makes standing cheap, not free." }, "voice.f0": { "typical": 400, "low": 200, "high": 500, "unit": "Hz, the lower fundamental", "tier": "contested", "source": "Briefer EF, Maigrot A-L, Mandel R, Briefer Freymond S, Bachmann I, Hillmann E (2015), Sci Rep 5:9989, doi:10.1038/srep09989, 267 whinnies from 18 horses. The 2026 mechanism paper's abstract instead gives the lower fundamental as approximately 200 Hz.", "note": "The two papers from overlapping groups give different values, probably because the 2026 figure comes partly from excised larynges. The page says so rather than picking one." }, "voice.g0": { "typical": 1500, "low": 1000, "high": 2000, "unit": "Hz, the higher fundamental", "tier": "established", "source": "Briefer EF et al. (2015), Sci Rep 5:9989. Lefevre RA et al. (2026), Current Biology, doi:10.1016/j.cub.2026.01.004, abstract verbatim: 'their whinnies contain a very high fundamental frequency (>1,000 Hz) in addition to a second, lower one'.", "note": "" }, "voice.biphonicShare": { "typical": 100, "unit": "per cent of analysed whinnies containing two fundamentals", "tier": "established", "source": "Briefer EF et al. (2015), Sci Rep 5:9989, across 267 whinnies from 18 horses.", "note": "Not a tendency. Every one." }, "voice.whinnies": { "typical": 267, "unit": "whinnies analysed", "tier": "established", "source": "Briefer EF et al. (2015): 267 whinnies, 201 negative and 66 positive, from 18 of 20 horses tested on five Swiss farms.", "note": "" }, "voice.measuredDeviation": { "typical": 0.227, "unit": "mean distance from the band ratio to the nearest whole number, real whinny", "tier": "derived", "source": "Measured in this page and in research/the-conditional-horse/verify.mjs from the published recording at /strata/the-conditional-horse/media/whinny-briefer-2015.wav, 328 frames.", "note": "" }, "voice.oneVoiceDeviation": { "typical": 0.003, "unit": "the same statistic for one synthesised voice with 6 per cent vibrato", "tier": "derived", "source": "Computed by the same code on a synthesised control. A single harmonic stack cannot drift off a whole number however far its pitch slides.", "note": "The positive control." }, "voice.twoVoiceDeviation": { "typical": 0.216, "unit": "the same statistic for two independent synthesised voices", "tier": "derived", "source": "Computed by the same code on a synthesised control with two voices sliding independently.", "note": "The negative control. The real horse sits here." }, "mane.studies": { "typical": 0, "unit": "experimental studies of what a horse's mane does", "tier": "established", "source": "A search of the veterinary, behavioural and zoological literature for a test of any function of the equid mane returned nothing. This page found no experiment, on any of the four standard explanations, conducted on an equid mane.", "note": "The absence is the finding." }, "mane.side": { "typical": 69, "unit": "per cent of horses whose mane falls to the right", "tier": "thin", "source": "Whishaw IQ & Kolb B (2017), 526 three-year-old American Quarter Horses: 69 per cent right, 31 per cent left, stronger in mares (74 per cent) than males (65 per cent), with no relationship to reining performance.", "note": "This is the entire quantitative literature on the mane as a structure: which side it falls on." }, "mane.flyLegs": { "low": 70, "typical": 76, "high": 100, "unit": "per cent of biting-fly landings that are on the legs and lower body", "tier": "established", "source": "Tabanid landing distributions: 76 per cent on the legs in cattle, 70 to 100 per cent on the legs in horses.", "note": "Two things are true at once and the page states both. Tabanid horseflies land overwhelmingly on the legs and lower body, so the crest is not where THEY go. But biting midges are the opposite: on a bait horse in Ireland the preferential landing and blood-feeding sites were along the mane and the lower legs. So the mane region has been measured, and it is a place biting insects go to rather than a place they avoid, which is the wrong way round for the protection story." }, "police.engagementRatio": { "typical": 6.5, "unit": "times as many public engagements per shift, mounted against foot", "tier": "contested", "source": "Giacomantonio C, Bradford B, Davies M, Martin R (2015), Making and Breaking Barriers: Assessing the value of mounted police units in the UK, RAND RR-830-ACPO, doi:10.7249/RR830, p.57, verbatim: 'mounted patrols in the experimental period generated approximately 6.5 times as many engagements over an equivalent period as their counterparts on foot in the control sites, which in real terms amounts to on average 332 engagements per shift for a mounted officer and 50 for an officer on foot.'", "note": "A quasi-experiment, and the report says so in its own words: the treatment was not randomised and it states that a direct causal effect cannot be demonstrated. There is no randomised trial of mounted police patrol anywhere in the literature." }, "police.mountedEngagements": { "typical": 332, "unit": "engagements per mounted shift", "tier": "established", "source": "RAND RR-830-ACPO (2015), Figure 3.10: acknowledgements 246, multiple encounters 74, encounters 9, interactions 12.", "note": "" }, "police.footEngagements": { "typical": 50, "unit": "engagements per foot shift", "tier": "established", "source": "RAND RR-830-ACPO (2015), Figure 3.10: acknowledgements 34, multiple encounters 2, encounters 10, interactions 12.", "note": "" }, "police.interactionsBoth": { "typical": 12, "unit": "engagements over a minute long, per shift, mounted AND on foot", "tier": "established", "source": "RAND RR-830-ACPO (2015), Figure 3.10. The two columns are identical at 12 each.", "note": "The 6.5 times is made entirely of noticing. The substantive conversations are the same number." }, "police.mountedEyeHeight": { "typical": 2.48, "low": 2.43, "high": 2.53, "unit": "metres, rider's eye above the ground", "tier": "derived", "source": "Derived: withers height by the hand convention (16.2 hands = 167.6 cm) plus sitting eye height of 80.45 cm from ANSUR II. No published measurement of saddle seat height above ground was found. The British Design Manual for Roads and Bridges independently specifies an equestrian eye height range of 1.5 to 2.7 metres, and this derivation sits inside it.", "note": "An estimate, and it is marked as one wherever it appears." }, "police.footEyeHeight": { "typical": 1.64, "unit": "metres, standing eye height", "tier": "established", "source": "ANSUR II derived measure D16, male mean 164.24 cm (SD 6.65).", "note": "" }, "police.crowdHeight": { "typical": 1.686, "unit": "metres, head-top height of an adult crowd", "tier": "established", "source": "Mid-sex adult stature. The male figure used for the comparison is 175.5 cm.", "note": "" }, "police.designUpperBound": { "typical": 2.7, "unit": "metres, the upper equestrian eye height in the British road design standard", "tier": "established", "source": "Design Manual for Roads and Bridges CD 143 version 2.0.1, verbatim: \"'Y' distances shall be measured from an eye height of 1.5 metres to 2.7 metres for equestrians.\" The clause numbers this page first printed for that sentence were wrong, and the audit that caught them is the reason they are not printed now.", "note": "An independent bound on the derived rider eye height below, and a nice one: a design standard's ceiling should exceed a typical adult on a large horse, and it does." }, "police.tenFootActual": { "typical": 2.6, "unit": "metres, the real top of a helmeted officer on a 16.2 hand horse", "tier": "derived", "source": "Derived from the same figures. Ten feet is 3.05 metres, so the nickname overstates it by about 45 centimetres.", "note": "" }, "police.footClearance": { "typical": -4.4, "unit": "centimetres of a foot officer's eye above an adult crowd's head-top plane", "tier": "derived", "source": "1.6424 metres minus 1.686 metres. Negative: a foot officer cannot see over a crowd of adults at any distance.", "note": "" }, "police.mountedClearance": { "typical": 79, "unit": "centimetres of a mounted officer's eye above the same plane", "tier": "derived", "source": "2.48 metres minus 1.686 metres.", "note": "Not a multiplier. A change of state." }, "mane.erectRows": { "typical": 6, "unit": "rows of the table with an erect mane", "tier": "derived", "source": "Counted from the table in this file, which carries a source per row. Computed in the page and asserted in the check.", "note": "" }, "mane.fallingRows": { "typical": 1, "unit": "rows of the table with a falling mane", "tier": "derived", "source": "Counted from the same table. The domestic horse.", "note": "" }, "hoof.shoeWearReduction": { "low": 57, "typical": 61, "high": 65, "unit": "per cent reduction in wear at the toe when shod", "tier": "thin", "source": "Malone SR & Davies HMS (2019), Animals 9:1017, the one crossover study of the question: eleven mares, seven weeks shod and seven barefoot, on sand.", "note": "At the toe only. At the medial and lateral wall sites the same study found no statistically detectable effect. A shoe does not stop wear; it slows it, at one place on the foot, in one study, on one surface." }, "eye.jumpOdds": { "typical": 0.874, "low": 0.732, "high": 1.045, "unit": "univariable odds ratio for eye covering, 95% CI", "tier": "contested", "source": "Allen S et al. (2025), Equine Vet J 57:870-877, 384,408 British jump starts, eye covering screened among 101 risk factors: hurdle univariable OR 0.874 (0.732 to 1.045), p = 0.139. Absent from the steeplechase screen and in neither final model.", "note": "Non-significantly protective, which is the opposite direction to the flat-racing study. The two are not a head-to-head: different codes, different years, different definitions of the exposure, and one distinguishes first-time use where the other does not." }, "eye.jumpStarts": { "typical": 384408, "unit": "British jump starts analysed", "tier": "established", "source": "Allen S et al. (2025), Equine Vet J 57:870-877.", "note": "" }, "eye.maskUlcers": { "typical": 1, "unit": "studies that have evaluated whether a fly mask prevents anything", "tier": "thin", "source": "Ludwig et al. (2025), on corneal ulceration: seasonal fly-mask use was unrelated to corneal ulcers, and year-round use was significantly associated with MORE repeat ulcers (p < 0.0001). Owner-reported.", "note": "One study, one outcome, and not simply null: it points the wrong way for the mask. Nothing has tested a mask against ocular squamous cell carcinoma, the disease whose mechanism is the real argument for one." }, "sleep.standingRemEpisodes": { "typical": 60, "high": 199, "unit": "REM-classified epochs a day recorded in STANDING horses that would not lie down", "tier": "contested", "source": "The two largest equine polysomnography series score REM epochs in standing horses routinely; Williams DC et al. (2008) recorded standing REM on surface EEG in one of five horses, with numerous partial collapses.", "note": "This is why the page does not say REM happens only lying down. Healthy horses with normal lying behaviour essentially never SUSTAIN it standing, because the atonia brings them down within seconds and wakes them. Horses that cannot lie down do enter it on their feet, and fall over." }, "mane.maneMidges": { "typical": 40.3, "unit": "per cent of midges attracted to a bait horse that took a full blood meal", "tier": "established", "source": "Townley P, Baker KP, Quinn PJ (1984), Equine Vet J 16:117-120, doi:10.1111/j.2042-3306.1984.tb01876.x, verbatim: 'Overall, the preferential landing sites for midges were along the mane and lower leg regions. Few culicoides were attracted to the head, front and underside of the animal... Of 10,178 midges attracted to the bait, 4097 (40.3 per cent) engorged; the majority of the species taking full blood meals fed on the mane and lower legs.'", "note": "Forty years old, and it is the measurement that the insect-protection hypothesis is usually asserted without." } }, "surfacePresets": [ { "id": "stabled", "label": "stabled, winter, shod", "growth": 0.18, "wear": 0.06, "note": "Reilly and colleagues' control group over a British winter, with Malone and Davies' shod wear rate. The least wear anyone has measured." }, { "id": "sand-shod", "label": "sand paddock, shod", "growth": 0.197, "wear": 0.059, "note": "Malone and Davies 2019: eleven Quarter Horse mares, seven weeks shod and seven barefoot." }, { "id": "sand-bare", "label": "sand paddock, barefoot", "growth": 0.238, "wear": 0.169, "note": "The same eleven mares, barefoot. Note that the barefoot feet also GREW faster, though not significantly so in this study." }, { "id": "feral-low", "label": "summer pasture, low wear", "growth": 0.33, "wear": 0.24, "note": "Florence and McDonnell's semi-feral ponies, self-trimming through a summer. Quoted at second hand." }, { "id": "feral-high", "label": "summer pasture, high wear", "growth": 0.35, "wear": 0.52, "note": "The same ponies at the high-wear end, and the only published case where the drain beats the tap. This is what a foot in deficit looks like, and it happened on grass." } ], "devices": [ { "id": "none", "name": "A bare head", "what": "Nothing over the eyes.", "targets": "nothing", "measured": "not applicable", "tier": "established", "source": "The field as reconstructed above.", "cuts": [] }, { "id": "blinkers", "name": "Blinkers", "what": "Cups beside and behind each eye. The British Horseracing Authority defines them as 'cutting out all vision to the rear but permitting full forward vision'.", "targets": "the monocular rear field, which is the low-acuity motion-detecting part", "measured": "never, by anyone", "tier": "derived", "source": "BHA Race Manual Schedule 4, definitions. No study of what a blinker removes in degrees was found in the veterinary or vision literature.", "cuts": [ [ 180, 130 ] ] }, { "id": "visor", "name": "A visor", "what": "Blinkers with holes cut in the cowls, which the rulebook says permit 'limited side or rear vision'.", "targets": "part of the monocular rear field", "measured": "never, by anyone", "tier": "derived", "source": "BHA Race Manual Schedule 4.", "cuts": [ [ 180, 80 ] ] }, { "id": "eyecover", "name": "A one-eyed cover", "what": "One eye completely covered by an opaque cover. The rulebook calls this an eyecover and counts it as a separate declarable item.", "targets": "one eye's entire field, including its half of the binocular window", "measured": "never, by anyone", "tier": "derived", "source": "BHA Race Manual Schedule 4.", "cuts": [ [ 65, 195 ] ] }, { "id": "shadowroll", "name": "A shadow roll", "what": "A roll of sheepskin on the noseband, sitting above the nostrils, intended to stop the horse seeing shadows on the track.", "targets": "the binocular window itself, downwards, which no other device on this list touches", "measured": "never, and there is no peer-reviewed literature on the device at all", "tier": "thin", "source": "Trade sources only. A search of Europe PMC for 'shadow roll' returns a spaceflight paper and a veterinary dictionary.", "cuts": [], "highlight": "binocular" }, { "id": "flymask", "name": "A fly mask", "what": "Mesh over the eyes, aimed at insects and ultraviolet light rather than at the field of view.", "targets": "photons and flies, not field", "measured": "no published transmittance measurement of any equine fly-mask mesh exists", "tier": "thin", "source": "Commercial claims of 90 to 99 per cent UV blocking. No peer-reviewed measurement found.", "cuts": [], "highlight": "none" }, { "id": "bonnet", "name": "An ear bonnet", "what": "Ear covers, sometimes with a fly fringe. The device most often lumped in with blinkers, and it is not a vision device at all.", "targets": "sound", "measured": "never in decibels; one study measured the horses' responses instead", "tier": "thin", "source": "Hole C, Murray R, Marlin D, Freeman P (2023), Animals 13:1574, doi:10.3390/ani13091574, 18 horses, crossover: mean heart rate 46.3 bpm with covers against 50.1 without.", "cuts": [], "highlight": "none" }, { "id": "blindfold", "name": "A blindfold", "what": "Everything. Used for loading, transport and rescue, on the belief that a horse that cannot see will follow.", "targets": "the entire visual field", "measured": "the field is not measured, but the effect on handling is", "tier": "established", "source": "Copelin C, Hayman B, Bergeron R, Merkies K (2024), Appl Anim Behav Sci 271:106180, doi:10.1016/j.applanim.2024.106180; Parker R et al. (2004), Animal Welfare 13:433-437, doi:10.1017/S0962728600028694.", "cuts": [ [ 0, 360 ] ] } ], "equids": [ { "common": "Domestic horse", "binomial": "Equus caballus", "mane": "falling", "forelock": "present", "source": "Groves CP (2002), Taxonomy of living Equidae, ch.8 p.108, subgenus Equus: the mane 'tends, at least in winter and/or with increasing age, to fall to one side'. Lydekker 1912 key p.176: 'Mane long and pendent, with a forelock'.", "tier": "established" }, { "common": "Przewalski's horse", "binomial": "Equus ferus przewalskii", "mane": "erect", "forelock": "absent", "source": "IUCN 2002 p.94, verbatim and the only occurrence of the word 'forelock' in the entire 204-page volume: 'the manes of Przewalski's horses are erect with no forelock ... Przewalski horses, contrary to domestic horses, shed their tail and mane hair once per year'. Complicated by Groves' own subgeneric diagnosis, which covers this animal too and describes a mane that falls with winter and age.", "tier": "contested" }, { "common": "African wild ass", "binomial": "Equus africanus", "mane": "erect", "forelock": "not described", "source": "Groves CP (2002) ch.8 p.113, subgenus Asinus: 'a long, thin scruffy mane'. No forelock is described; silence rather than absence.", "tier": "established" }, { "common": "Asiatic wild ass, onager", "binomial": "Equus hemionus", "mane": "erect", "forelock": "not described", "source": "Groves CP (2002) ch.8 pp.109 and 110: 'the short, seemingly clipped mane'; 'The mane is very short, clipped'. Groves does not mention a forelock for this animal; the word appears exactly once in that whole volume, in the Przewalski chapter, so this cell records silence rather than absence.", "tier": "established" }, { "common": "Kiang", "binomial": "Equus kiang", "mane": "erect", "forelock": "not described", "source": "Groves CP (2002) ch.8 p.109 calls the mane 'relatively long'; the species chapter of the same volume, p.84, calls it 'upright and relatively short'. The volume contradicts itself 25 pages apart, and this page reports that rather than choosing. Groves does not mention a forelock for this animal; the word appears exactly once in that whole volume, in the Przewalski chapter, so this cell records silence rather than absence.", "tier": "contested" }, { "common": "Plains zebra", "binomial": "Equus quagga", "mane": "variable", "forelock": "disputed", "source": "Groves CP (2002) ch.8 p.115: the mane 'varies from long, thick, and neat to shorter, thinner, and even absent altogether'. And p.118, on northern populations: 'manes are, in three-quarters of individuals, either sparse and tufty or completely absent ... the character is apparently fixed'.", "tier": "established" }, { "common": "Mountain zebra", "binomial": "Equus zebra", "mane": "erect", "forelock": "not described", "source": "Groves CP (2002) ch.8 p.115: 'the long, rather thick upright mane'. IUCN 2002 p.40 notes Hartmann's mane 'comes further forward between the ears'.", "tier": "established" }, { "common": "Grevy's zebra", "binomial": "Equus grevyi", "mane": "erect", "forelock": "not described", "source": "Groves CP (2002) ch.8 p.118: 'a long thick upright mane'.", "tier": "established" } ], "maneHypotheses": [ { "claim": "It keeps the neck warm", "wouldBeTestedBy": "Instrument a maned and a shorn neck, or measure heat loss across the crest with and without hair, in an equid.", "whatExists": "Nothing on any equid. The one large mammal whose mane has been instrumented is the lion, and the measurement cut against the thermal story: maned males ran mean core temperature 0.2 degrees C LOWER than females.", "tier": "untested" }, { "claim": "It protects against biting flies", "wouldBeTestedBy": "Count fly landings on the crest with the mane present, pulled, or hogged.", "whatExists": "Measured, and pointing the wrong way. Tabanid flies land overwhelmingly on the legs and lower body, 76 per cent on the legs in cattle. But biting midges were measured on a bait horse in 1984 and the mane was one of their two PREFERRED landing and blood-feeding sites. The mane region is somewhere biting insects go, not somewhere they are kept off.", "tier": "indirect" }, { "claim": "It signals status or fitness to other horses", "wouldBeTestedBy": "Relate mane condition to rank or to mate choice, or run a playback or model-presentation experiment.", "whatExists": "Nothing on any equid. The entire quantitative literature on the domestic horse's mane is a study of which side it falls on: 526 Quarter Horses, 69 per cent right.", "tier": "untested" }, { "claim": "It protects the neck in fighting", "wouldBeTestedBy": "Relate bite placement in real fights to mane coverage, or measure what a mane's worth of hair actually absorbs.", "whatExists": "Nothing on any equid. Tested once on any mammal, in lions: the mane area was not a preferential target of attacks and mane injuries were not more lethal, and the authors found no compelling evidence of effective protection, concluding that protection is at most secondary to signalling.", "tier": "indirect" }, { "claim": "The falling mane is part of the domestication syndrome", "wouldBeTestedBy": "A genetic mapping of mane form, or the trait's appearance alongside others in a domestication experiment.", "whatExists": "The word 'mane' does not appear in the canonical published table of domestication-syndrome traits, and the syndrome itself is under serious challenge. No genetics of mane or forelock form in horses was found.", "tier": "untested" } ] }