Feral horses, also known as free-roaming or wild horses, are equines that live in natural environments without direct human management. They are descendants of domesticated horses that have adapted to living in the wild over generations. These populations are found in various regions worldwide and exhibit behaviors and social structures distinct from domesticated horses. In contrast, domesticated horses are bred and raised under human care, often for specific purposes such as work, recreation, or sport. The study of feral horses involves understanding their ecology, behavior, and genetics, while research on domesticated horses often focuses on health, management, and performance. This page compiles peer-reviewed research studies and scholarly articles that explore the differences and similarities between feral and domesticated horses, including their behavior, physiology, and impact on ecosystems.
Kaseda Y, Ogawa H, Khalil AM.Misaki feral horses were separated into 2 herds and the difference between dispersal from natal group (natal dispersal) and dispersal from natal area (natal emigration) was studied. The causes of dispersal and emigration and their effects on harem formation were studied 1979-1994. The number of horses ranged from 73 (mature males: 8, mature females: 26, young males: 8, young females: 3, colt foals: 6, filly foals: 10 and geldings: 12) in 1979 and 86 (mature males: 14, mature females: 37, young males: 12, young females: 7, colt foals: 5, filly foals: 7 and geldings: 4) in 1994 when the present ...
Kirkpatrick JF, Turner JW, Liu IK, Fayrer-Hosken R, Rutberg AT.Non-lethal management methods are required for wild equids that are protected by law and for deer inhabiting areas where lethal controls are not legal or safe. Single or multiple inoculations of porcine zona pellucida (PZP) vaccine have been delivered to wild horses and deer by means of darts. Contraceptive efficacy in horses after two inoculations ranged from 90% to 100%, and after a single inoculation ranged from 19% to 28%. Mares given a controlled-release form of the vaccine had foaling rates ranging from 7% to 20%. No detectable changes in social organization or behaviours among treated h...
Vagedes K.The bone finds from the neolithic settlement in Pestenacker (near Landsberg am Lech) date back to the second half of the 4th millennium BC (Altheim). Like in any other late neolithic horse bones, the question we have to deal with is whether they represent the remains of wild horse or early domestic horse, as we do not know for certain yet the date of the earliest domestic horses' occurrence in Middle Europe. The post pleistocene distribution of the wild horse is described. For a long time people thought that hardly any wild horses existed in post pleistocene Middle Europe any longer, due to th...
Kirkpatrick JF, Turner JW, Liu IK, Fayrer-Hosken R.A unique application of pig zona pellucida (PZP) immunocontraception is the control of wildlife populations. A native PZP vaccine has been successfully applied to wild horse and donkey populations. A single annual booster inoculation was capable of maintaining contraception. Seven consecutive years of PZP treatment in wild mares resulted in no detectable debilitating side effects, and reversibility of contraception has been documented among mares treated for up to 4 consecutive years. Long-term treatment (5-7 years) is associated with some ovulation failure and depressed urinary oestrogen conc...
Daels PF, Hughes JP.The purpose of this study was to develop a contraceptive method for feral horses. The feral horse population has increased significantly in recent years despite attempts to control numbers. As in most wild animal population control programs, contraceptive methods must be easy to apply, cause minimal disruption to the social structure and be fully reversible. In the present study, we tested the effectiveness of an intrauterine device (IUD) for fertility control in mares. Six mares were fitted with a silastic O-ring-shaped IUD on July 1 of Year 1. The IUD-treated mares were turned out with 12 no...
Kaseda Y, Khalil AM, Ogawa H.The stability of relationships between harem stallions and mares (consort relations) was investigated and the durations of inter partum intervals were determined in order to establish if there was any correlation between the stability of consort relation and reproductive success of mares in Misaki feral horses. Thirty-four mares were observed continuously for more than 5 years. The lifetime stability was 80-100% (mean 92.4%) for 16 mares, 60-79% (mean 70.4%) for 10 mares and 0-59% (mean 27.9%) for 8 mares. The continuous length (years) of specific consort relations was 2-10 years and was found...
Bowling AT.The genetic make-up of Great Basin wild (feral) horses was investigated by blood typing studies. Blood samples of 975 feral horses from seven trap sites in Nevada and Oregon were tested by serological and electrophoretic techniques for genetic markers at 19 polymorphic loci. The average number of variants for the seven feral populations [72.1 +/- 3.2 (SEM), range 62-85] was not significantly different from that of 16 domestic breeds (75.0 +/- 11.5, range 58-105). The expected average frequency of heterozygotes per locus (average heterozygosity) for the feral populations (0.402 +/- 0.009, range...
Dvoĭnos GM, Kharchenko VA, Zviagnitsova NS.The helminth fauna of 24 kulans from Askaniya-Nova and Badkhyz was studied. 42 species of helminths were found, 34 of which belong to strongylids. The helminth species composition of kulan is similar to that of other species of horses. This is a result of an intensive parasite exchange in the historical past when numerous populations of different Equidae species made long seasonal migrations over steppe inter-river lands of Asia and grazed for some time on common pastures.
Plotka ED, Vevea DN, Eagle TC, Tester JR, Siniff DB.Homogeneous Silastic rods containing ethinylestradiol (EE) (1.5 or 4 g), estradiol-17 beta (E) (4 g) or progesterone (P) (6 g) were implanted into feral mares (Equus caballus) between 4- and 10-yr-old. Six treatment groups (greater than or equal to 10 mares/group) of non-pregnant mares received 36 g P and 12 g E (P+E), 36 g P and 8 g EE (P+HEE), 1.5 g EE (LEE), 3 g EE (MEE, 8 g EE (HEE) or control-implanted mares (CI). CI received implants containing no steroid. Two groups of pregnant mares received P+HEE or HEE. Stallions were placed with the mares 15 to 26 mo after implanting. Blood was coll...
Kirkpatrick JF, Liu IM, Turner JW, Naugle R, Keiper R.Ten feral mares free-roaming in Maryland, USA, were inoculated with porcine zonae pellucidae (PZP) protein before the breeding season for three consecutive years (1988-90). Ovarian function was monitored for 51 days during the peak of the breeding season after the third annual PZP inoculation, in seven of these mares and in four untreated control mares, by means of urinary oestrone conjugates and nonspecific progesterone metabolites. None of the ten inoculated mares became pregnant in 1990, compared with 55% of 20 control mares, which included two of the four monitored for ovarian function. Th...
Rudman R, Keiper RR.The summer body condition of 47 adult feral ponies on Assateague Island (off the coast of Maryland, USA) was assessed in June 1988 using a visual body condition scoring system. Winter body condition for 36 of the ponies was assessed in February and March, 1989. The ponies were categorised by gender, reproductive status and location on the island, and body condition scores of the ponies in each category were then compared by statistical analyses. No significant seasonal differences were found in the body conditions of the ponies. However, body condition of stallions was better than that of mare...
Houpt KA.Some of the techniques that may be used to study social, reproductive, and ingestive behavior in horses are described in this paper. One of the aspects of equine social behavior is the dominance hierarchy or patterns of agonistic behavior. Paired or group feeding from a single food source may be used to determine dominance hierarchies quickly. Focal animal studies of undisturbed groups of horses may also be used; this method takes longer, but may reveal affiliative as well as agonistic relationships among the horses. Reproductive behavior includes flehmen, the functional significance of which ...
Sneddon JC, van der Walt JG, Mitchell G.This study set out to investigate tolerance of the body water pool to short-term water deprivation in horses and, in particular, to assess whether feral horses from the Namib Desert showed tolerance to dehydration superior to Transvaal. Hydration status was compared in six feral horses from the Namib Desert and in six Boerperd farm horses under conditions of normal hydration and after 72 h of dehydration. Under normal hydration, the two groups did not differ significantly in water intake, plasma sodium and potassium concentrations, plasma osmolality, hematocrit, total plasma protein, body wate...
Kirkpatrick JF, Shldeler SE, Lasley BL, Turner JW.This study was carried out to develop an accurate, rapid and inexpensive method for diagnosing pregnancy in uncaptured feral horses by analysis of fecal steroid metabolites and to compare the accuracy of this method with diagnosis by urinary estrone conjugates (E(1)C). Paired urine and fecal samples were collected from 40 sexually mature feral mares during August and October. Urine samples were extracted directly from the soil and analyzed by enzymeimmunoassay (EIA) for E(1)C. Water extracts of fecal samples were assayed by EIA for E(1)C and nonspecific progesterone metabolites (iPdG). Urinary...
Kirkpatrick JF, Liu IM, Turner JW, Bernoco M.Twenty-six free-roaming feral mares were immunized against porcine zonae pellucidae (PZP) between February and May, 1988. Eight sexually mature mares received 2 inoculations 2 weeks apart, and 18 mares received 3 inoculations at intervals of 2 and 4 weeks. Analysis of urinary oestrone conjugates (E1C) and non-specific progesterone metabolites (iPdG) in samples collected in October, 1988, revealed that none of the 18 mares that received 3 and only 1 of the 6 mares that received two inoculations were pregnant, whereas 3 of 6 sham-injected control mares and 5 of 11 untreated mares were pregnant. ...
Lucas Z, Raeside JI, Betteridge KJ.Field observations of 400 totally unmanaged feral horses on Sable Island, Nova Scotia, were complemented by oestrogen determinations in faecal samples from 154 identified females over a 4-year period (454 mare-years). Of mares that were sampled throughout the year and subsequently produced foals, 92.1% exhibited elevated faecal oestrogens between 15 October and 30 March. The results confirm that faecal oestrogens are a useful indicator of pregnancy after approximately 120 days gestation. Distribution of foaling resembled that seen in other feral populations, with 95% of births occurring from A...
Cancedda M.In this paper some considerations on the environment of the 42 Kmq of the volcanic-basaltic Giara tableland are discussed. Conditioning by the environment and its effect on the distribution of a population of 712 horses is illustrated in view of their social and behavioural organization.
Wiesner H, von Hegel G.Successful immobilisation of Przewalski's horses and zebras was obtained by using a combination of STH 2130 (Boehringer) and Tiletamin/Zolazepam.
Bowling AT, Gordon L, Penedo MC, Wictum E, Beebout J.We describe a method for agarose IEF under acid conditions in which a single gel can be used to diagnose from equine red cell lysates genetic variants for carbonic anhydrase (CA) and catalase (Cat). Family and population data for 4801 horses of 27 breeds and seven trap sites of Great Basin feral horses are presented to support the presence of a sixth CA allele, CAE, which has been recognized previously, but not described by published data. Allelic frequencies for the two systems suggest it may be appropriate to use this gel for parentage verification programmes or to obtain population data for...
Plotka ED, Vevea DN, Eagle TC, Siniff DB, Tester JR.Ovarian function was monitored for 33 mo in captive feral mares (Equus caballus) by following serum progesterone (P) levels. A P level greater than 2.0 ng/ml was considered indicative of ovulation. Feral mares were seasonally polyestrus with the majority of animals ovulating between May and October. During the first year after capture, none of the mares ovulated during the anestrous season. However, in subsequent years, approximately 10% of mares ovulated during the months of November, January and February. P levels during the luteal phase of the cycle ranged from 2.0 to 21.0 ng/ml which were ...
Blakley BR, Skelley KW.Normal cholinesterase activity in brain tissue was measured in various mammalian and avain species. The cholinesterase activity in the cerebrum of cattle, swine, sheep and horses was approximately 2-3 umoles/min/g of tissue in each instance. The whole brain cholinesterase activity of small feral mammals was approximately 2 to 5 fold greater than the domestic animals. Considerable interspecies variability was present in the feral mammals. Similar variability was also observed in the avian brain cholinesterase determinations. The avian whole brain cholinesterase activities ranged from 9.78 to 21...
Plotka ED, Eagle TC, Vevea DN, Koller AL, Siniff DB, Tester JR, Seal US.Five groups of 30 captive feral mares each were implanted with silastic rods containing estradiol (E) and/or progesterone (P): E only with 8 g, P only with 24 g, P+HE with 8 g P + 8 g E, HP+E with 12 g P + 4 g E, HP+LE with 12 g P + 2 g E. Arbitrary group designations were differentiated by relative high (H) and low (L) amounts of steroid. Thirty mares received silastic rods containing no hormone (CI). Five mares from each group were bled every 2 wk for 4 mo and monthly for another 5 mo. All mares were tested for estrus by allowing them to stand in an alley between two pens of stallions and vi...
Penzhorn BL, van der Merwe NJ.Testis mass of adult Cape mountain zebra stallions (mean 70.0 g) was appreciably less than that of other zebra species and domestic horses. The histological appearance of the testes of 11-, 24- and 29-month-old colts was typically prepubertal. Spermatogenic activity of a 4-year-old stallion obtained at the end of summer was at a very low level, while a 4.5-year-old stallion obtained 6 weeks after the winter solstice showed a marked increase in spermatogenesis compared with the 4-year-old. Stallions 6.5-19 years of age collected in different seasons all showed active spermatogenesis.
Plotka ED, Eagle TC, Gaulke SJ, Tester JR, Siniff DB.Blood was collected from 486 feral horses of mixed sex and age classes captured from three wild horse management areas in Nevada and Oregon from December 1985 to February 1986. Males were significantly outnumbered by females in the Flanigan area, but both sexes were represented in approximately equal numbers in the Wassuk and Beaty's Butte areas. Hematology and chemistry values averaged 16.4 +/- 0.11, 46.3 +/- 0.28, 9.9 +/- 0.07, 6.9 +/- 0.10, 47.1 +/- 0.24, 16.6 +/- 0.09, 35.2 +/- 0.09, 10.4 +/- 0.14 and 23.4 +/- 0.25 for hemoglobin (HGB), hematocrit (HCT), red blood cells (RBC), white blood ...
Plotka ED, Seal US, Eagle TC, Asa CS, Tester JR, Siniff DB.Forty-eight newly captured free-ranging feral stallions (Equus caballus) from two different locations and six captive stallions were immobilized using combinations of etorphine hydrochloride, xylazine hydrochloride and atropine sulfate with or without acepromazine. Six animals were immobilized twice, 1 mo apart. The drugs were administered either intramuscularly (n = 13) or intravenously (n = 44). Mean immobilization time (+/- SE) after intravenous (i.v.) injection of etorphine, xylazine and atropine was 55 +/- 4 sec (range 20 to 185 sec) compared to 708 +/- 131 sec (range 390 to 1,140 sec) fo...
Keiper RR.Socially feral horses live in stable social groups characterized by one adult male, a number of adult females, and their offspring up to 2 years of age. Extra males either live by themselves or with other males in bachelor groups. The bands occupy nondefended home ranges that often overlap. Many abnormal behaviors seen in domestic horses occur because some aspect of their normal social behavior cannot be carried out in captivity.
Asa CS.Behavior during the estrous phase of the ovulatory cycle of the mare is analogous in most ways to that of estrous females of other species. Proceptive behaviors bring the mare into the proximity of the male and attract his attention. Positioning facilitates mounting, intromission, and ejaculation. Estrous signs appear to be more intense in the few days prior to ovulation than during the transition periods that separate the recurring estrous and diestrous phases. Sexual behavior is absent during diestrus. Detection of estrus in mares is problematic in that it requires the presence (or at least ...
Clark GG, Crabbs CL, Bailey CL, Calisher CH, Craig GB.An arbovirus survey was conducted during August 1985 at White Sands Missile Range in southcentral New Mexico following a suspected arboviral disease epizootic among feral horses. A total of 20,566 mosquitoes (18,505 females and 2,061 males) and 8,900 biting gnats were collected and assayed for virus. Female mosquitoes were principally Aedes campestris (54.8%), Aedes dorsalis (30.4%) and Culex tarsalis (13.2%). Arboviruses were not isolated from biting gnats, but mosquitoes yielded a total of 37 viral isolates, including western equine encephalitis (WEE) (18), California serogroup (15), Cache V...
Rudik SK.The Ukraine is one of the centers of domestication of animals. Many archaeological excavations and chronicles evidence this. The wild horse tarpan was domesticated in Ukraine. There were huge herds of tarpans lived in Ukraine. Tarpans were distinguished for their speed, quality of their hooves (it was very important for the shoeless horses). The last tarpan mare was killed at Ukrainian territory at 1898. In contradistinction to the Eq. Prezewalskii the tarpan was the direct ancestor of the European domesticated horse breeds.
Michalski G, Earman S, Dahman C, Hershey RL, Mihevc T.Multiple stable isotope analysis can be a powerful technique in forensic sciences. Oxygen and nitrogen isotopes were used to determine the source of nitrate that was responsible for the poisoning deaths of 71 wild horses in the Nevada desert. The nitrate was present in a water-filled hole known as 'the Main Lake depression.' Nitrate from the Main Lake depression had delta(18)O and delta(15)N values that were very positive (+32 per thousand, +37 per thousand), and Delta(17)O values of approximately +2 per thousand. The isotopic data suggested that the most probable source of the nitrate was nit...
Vagedes K.The bone finds from the neolithic settlement in Pestenacker (near Landsberg am Lech) date back to the second half of the 4th millennium BC (Altheim). Like in any other late neolithic horse bones, the question we have to deal with is whether they represent the remains of wild horse or early domestic horse, as we do not know for certain yet the date of the earliest domestic horses' occurrence in Middle Europe. The post pleistocene distribution of the wild horse is described. For a long time people thought that hardly any wild horses existed in post pleistocene Middle Europe any longer, due to th...
Dvoĭnos GM, Kharchenko VA, Zviagnitsova NS.The helminth fauna of 24 kulans from Askaniya-Nova and Badkhyz was studied. 42 species of helminths were found, 34 of which belong to strongylids. The helminth species composition of kulan is similar to that of other species of horses. This is a result of an intensive parasite exchange in the historical past when numerous populations of different Equidae species made long seasonal migrations over steppe inter-river lands of Asia and grazed for some time on common pastures.
Pikuła R, Zaborski D, Grzesiak W, Smugała M.The aim of the present study was to analyse the mobility of Polish Konik horses in their natural environment. The study was conducted on a herd of 15 Polish Konik horses in 2018. The Global Positioning System (GPS) transmitter was used to track the horses' movements. Two habitats (forest and meadows), four seasons (autumn, winter, spring, and summer), and four times of the day (morning, midday, evening, and night) were distinguished. Season, habitat, and time of the day as well as the interaction among them significantly ( p < 0.0001 ) affected the mobility of Polish Konik horses. The use of ...
Pichardo M.Analysis of the morphological characters in North and South American horses present during Paleoindian time indicates that at least eight Equus ecospecies occurred in North America. In South America, Equus had radiated into four ecospecies, Hippidion had one, and Onohippidium had three geographically separate ecospecies. These species are found in archeological deposits ranging from ca. 13,000 to 8,000 yr B.P., in tropical habitats as well as in the high Andean and Patagonian colder ecotopes.
de Seve CW, Griffin SL.In recent years, the Bureau of Land Management's (BLM) Wild Horse and Burro Management program costs have increased dramatically due to a rise in the number of animals removed from public lands coupled with significantly decreased adoption rates. To assist with development and implementation of effective, cost-containing management programs, a robust economic model to project the costs and optimize outcomes of various management scenarios was created. For example, preliminary demonstration model runs show that by gradually replacing "removal-only" programs with contraception-and-removal progra...
Houpt KA.Some of the techniques that may be used to study social, reproductive, and ingestive behavior in horses are described in this paper. One of the aspects of equine social behavior is the dominance hierarchy or patterns of agonistic behavior. Paired or group feeding from a single food source may be used to determine dominance hierarchies quickly. Focal animal studies of undisturbed groups of horses may also be used; this method takes longer, but may reveal affiliative as well as agonistic relationships among the horses. Reproductive behavior includes flehmen, the functional significance of which ...
Gradil C, Joone C, Haire T, Fowler B, Zinchuk J, Davies CJ, Ball B.Fertility control of feral equids is difficult. A 4-month pilot study was conducted with a hormone-free intrauterine device (iUPOD). There was evaluation of i) device retention; ii) contraceptive efficacy; iii) fertility following device removal; iv) effects of device on estrous cycle periodicity and; v) abundance of biofilm on devices after removal from the uterus. The iUPODs were inserted trans-cervically in eight mares at random stages of the estrous cycle. Mares were confined in a paddock with a stallion the following day and remained with the stallion for 120 days. Transabdominal detectio...
Balko JA, Fogle C, Stuska SJ, Fogle JE, Posner LP.Butorphanol-azaperone-medetomidine (BAM™) has not been evaluated in horses. Objective: The objective of this study was to evaluate BAM™ for chemical restraint of feral horses. Methods: Retrospective and prospective descriptive studies. Methods: Data were collected retrospectively from medical records of 28 feral horses immobilised with BAM™ over a 6-year period. Prospectively, 0.0125 mL/kg bwt of BAM™ (butorphanol 27.3 mg/mL, azaperone 9.1 mg/mL and medetomidine 10.9 mg/mL) intramuscularly (im) was administered to eight stallions via dart, and once recumbent, 1.0 mg/kg bwt ketamin...
Lambert MS, Ozbay G, Richards GP.We evaluated the quality of seawater and ribbed mussels (Gukensia demissa) at six sites along the West Coast of Assateague Island National Seashore (ASIS), a barrier island popular with tourists and fishermen. Parameters evaluated were summertime temperature, pH, salinity, dissolved oxygen, total phosphorus, total ammonia nitrogen, and nitrite levels for seawater and total heterotrophic plate counts and total Vibrionaceae levels for the ribbed mussels. Approximately 150 feral horses (Equus caballus) are located on ASIS and, combined with agricultural runoff from animals and croplands, local wi...
Hampson BA, de Laat MA, Mills PC, Pollitt CC.To determine the effect of various environmental conditions on the degree of hydration in hoof wall horn tissue from feral horses and investigate the effect of short-term foot soaking on moisture content in hoof wall and sole tissue in domestic horses. Methods: 40 feral horses from 3 environments (wet and boggy [n = 10], partially flooded [20], and constantly dry desert [10]) and 6 nonferal Quarter Horses. Methods: The percentage of moisture content of hoof wall samples from feral horses was measured in vitro. In a separate evaluation, the percentage of moisture content of hoof wall and sole t...
Lean NE, Franklin SH, Steel C, Woolford L, White J, Ahern BJ.Little is known about potential differences in the left recurrent laryngeal nerve (Lrln) and left cricoarytenoideus dorsalis (LCAD) muscle between domestic and feral horse populations. If a difference exists, feral horses may provide a useful control population for research related to recurrent laryngeal neuropathy (RLN) and increase our understanding of potential population pressures influencing the incidence RLN. The objective of this study was to compare the Lrln and LCAD of domestic and feral horses using histological and immunohistochemical techniques (IHC). Sixteen horses, domestic (n = ...
Thompson MA, McCann BE, Simmons RB, Rhen T.Contraceptive vaccines are used to reduce birth rates in wild and feral animal populations. While the immunocontraceptive GonaCon-Equine has proven effective in reducing fertility among female feral horses, there is individual variation in the duration of infertility following treatment. To identify genetic factors influencing the effectiveness of GonaCon-Equine, we conducted a genome-wide association study of 88 mares from a feral population genotyped using the Illumina GGP Equine 70k SNP array. Contraceptive treatment schedules and long-term foaling rates have been recorded for each individu...