普氏野马雄性杀婴行为及其对野马放归的影响

2001年8月在新疆卡拉麦里有蹄类自然保护区进行普氏野马在中国的首次再引入放归实验。在放归初期,放归普氏野马的野外种群数量增长缓慢,主要原因是由于繁殖群头马的频繁更替,新出生的部分幼驹死于头马的杀婴。2003年4月至2005年11月在野外共出生13匹幼驹,新生幼驹的死亡率46%,死于头马杀婴的个体占全部新生个体的38.5%,占全体死亡个体的83.3%,雄性杀婴行为是制约放归野马种群增长的主要因素,降低繁殖群头马的更替的频率是提高新生幼驹存活率的根本所在。     

繁衍生息之难

繁衍后代是动物的本能,也是一个物种持续的根本。放归野外的普氏野马能正常繁育后代,然而,严格的一雄多雌制度,使得家族群的内斗堪称野马版的《甄传》。头马杀婴行为和近亲繁殖现象,为野马放归后的自然繁衍带来难题。     

中国新疆放归普氏野马的繁殖状况

2001年8月在新疆卡拉麦里有蹄类自然保护区进行普氏野马在中国的首次再引入放归实验.2002-2006年在野外共繁殖24匹后代.平均繁殖率为38.72%,平均繁殖存活率为69.05%,繁殖季节头马的频繁更替是影响放归普氏野马繁殖率的主要因素.新生幼驹的平均死亡率为25%,其中83.3%死于头马的雄性杀婴.放归普氏野马的繁殖具有明显的季节性繁殖特征,其中有70.8%的幼驹集中在5-6月间出生,在4、5月份产驹比例分别占8.3%和37.5%.低于同期圈养18.3%和44.3%的产驹比例,6月份产驹比例占33.3%.高于同期圈养18.3%的产驹比例,结果表明:普氏野马放归后产驹高峰季节明显向后推迟,而放归后生存环境和食物资源供给方式的改变则是其繁殖季节产生推迟的主要原因.     

野放普氏野马(Equus przewalskii)家域面积及其影响因素

采用MCP方法研究了2011年至2012年新疆卡拉麦里山有蹄类自然保护区野放普氏野马家域的变化。通过方差分析验证了年间、季节间不同群体家域及其两两重叠无差异。以家族群大小为协变量进行了野放野马家域协方差分析。利用野放野马家族大小为协变量的协方差分析分析检验了野放野马家族大小与家域关系。结果表明:(1)野马平均家域面积由2011年的(20±2)km~2/匹扩大到2012年的(30±2)km~2/匹。对部分野放群体中头马未发生更替的野马群的研究表明,随着野马群体增大,其家域面积显著增大(P0.05)。(2)单因素方差分析显示,不同野马群的家域面积在不同年份差异显著,且春季家域秋季家域夏季家域。(3)2011年不同群家域两两间相互重叠面积与群大小无显著相关(r=0.256,P=0.5800.05)。而2012年野马群家域两两之间重叠面积有显著差异(F=4.521,df=8,P0.001)。家域两两相互重叠面积与群大小显著相关(r=0.706,P=0.0330.05)。(4)不同季节间野马群家域重叠面积有显著差异(F=5.695,df=8,P0.001)。5号群、7号群和8号群的自身家域重叠面积(P0.05),3号群、6号群和9号群的家域重叠面积(P0.05)。(5)影响野放野马家域面积的生物因子有草本盖度、灌木盖度,非生物因子主要有温度、湿度、风速、最近水源地距离和最近居民点距离等。温度与草本盖度是影响野放野马家域面积大小的主要因素,两者与野放野马家域面积显著相关(P0.01)。     

安西极旱荒漠国家级自然保护区重引入普氏野马繁殖成效与种群生存力分析

安西自然保护区放归的普氏野马是一个孤立封闭的小种群,种群数量增长极其缓慢,同时,面临着严峻的捕食压力和近交衰退。因此,对这个物种制定长期的自然保护计划是当务之急。本研究通过对重引入普氏野马种群繁殖力和种群生存力进行分析,结果表明：（1）安西保护区野马种群数量增长缓慢是由生育率（44.3%）低和幼驹死亡率（43.4%）高造成的,天敌捕食（35.3%）和疾病（26.5%）成为影响野马繁殖存活率的主要因素;普氏野马的繁殖具有明显的季节性特征,80.9%的幼驹出生在5月和6月;（2）种群生存力分析（PVA）预测本放归野马种群未来100年的灭绝概率是60%,野马种群数量达200匹以上才能保证100年后90%的存活率;（3）参数敏感度分析显示,外部因素--狼袭对保护区野马种群的灭绝和种群数量最具影响力,其次是决定生殖成功的内部因素--生育率、最大繁殖年龄;（4）保护区野马小种群效应明显,疾病和幼驹羸弱而死亡的比例高（分别为26.5%和8.8%）,合理的补充新个体是降低种群灭绝风险长期的管理对策。同时,减小狼对野马的捕食压力,加强幼驹的保护,是目前改善本区内普氏野马小种群生存状态的有效手段。     

重引入地生境对普氏野马胃肠道寄生虫疾病感染的风险评估

野生动物重引入是保护濒危种群的重要措施之一,但重引入放归地存在的疾病风险会影响重引入物种的健康并导致重引入项目的失败。疾病风险评估是用于识别、确定风险因子优先级和设计防控策略以应对风险的重要方法。为评估普氏野马（Equus przewalskii）重引入内蒙古大青山国家级自然保护区的疾病风险,本研究在传统文献研究的基础上,结合保护区内4个村庄83份家养马科动物粪便中寄生虫卵检测结果,进行专家赋分,确定威胁因子并评级,对影响普氏野马种群健康重要因素之一的寄生虫疾病进行风险评估,并提出相应的防控建议。本研究共确定了44种胃肠道寄生虫疾病,病原体分别隶属于5纲7目8科19属;其中高风险寄生虫疾病10种,中风险13种,低风险21种。小井村、奎素村和滴水村均为低风险区域,而厂汉脑包村属于高风险区域。重引入地周围的家马（E. caballus）和家驴（E. asinus）有与放归普氏野马交叉感染寄生虫的风险,但经严格的防控措施后,可以放归普氏野马。建议保护区内村庄限定家养马科动物活动范围,定期为家畜驱虫并清理圈舍,严格实行禁牧政策,增设远离村庄的普氏野马水源地,并对放归后普氏野马种群的寄生虫疾病进行长期监测与防控,从而有效防止寄生虫疾病的发生和传播。     

圈养和放归成年雌性普氏野马(Equus przewalskii)夏季昼间的摄食行为

2005至2006年的6～8月间,在新疆普氏野马饲养与繁殖研究中心和卡拉麦里山有蹄类自然保护区,采用全事件取样法和目标动物取样法相结合,研究了圈养和放归成年雌性普氏野马夏季昼间的摄食行为.结果表明,两组个体在摄食行为类型上存在一定的差异,圈养个体普遍具有舔盐和食粪行为,而放归个体不存在此类行为.经独立样本t 检验,得出两组个体的摄食和站立行为的时间分配存在显著差异(P＜0.05),而站息、卧息、运动和其它行为差异不显著(P＞0.05),总体上,两组普氏野马的摄食行为所占时间最多.圈养个体昼间具有3个摄食高峰(8:00～10:00、13:00～15:00、19:30～20:00),与人工投食时间相一致,而放归个体摄食高峰并不明显,仅在13:00～15:00之间出现一个明显的摄食低谷,表现出自然的摄食节律及对放归地夏季自然条件的适应.     

普氏野马繁殖群在组建和放归初期的争斗行为与社群等级建立

2007年5月下旬至6月下旬,针对新组群并放归于卡拉麦里有蹄类保护区第二放归点的普氏野马(Equus przewalskii)繁殖群,采用焦点动物取样法和全事件记录法,观测记录了组群和放归初期繁殖群内个体间的争斗行为(攻击行为和屈服行为),以优势指数法确定繁殖群内的个体等级序列。结果表明,新组群内个体的年龄与攻击行为发出次数不存在显著的相关性(r=0.60,t=1.62,rr0.05),攻击与屈服行为次数也无显著的相关性(r=0.56,t=1.41,rr0.05)。各个体之间从最初组群到野放争斗行为日趋减少,社群等级逐渐建立并趋于稳定。     

唐家河自然保护区扭角羚的兽群结构及数量分布

四川唐家河自然保护区有扭角羚480—520只。喜聚群活动,其兽群可分为家群、族群和聚集群。并随季节变化而有分群和合群现象。此外还有游离于群体之外的独羚,多为成年雄体。其兽群幼仔占17.52±6.48％,亚成体占17.25±9.16％,成体占65.23±12.59％;聚集群中成体雄雌比为1:2,雌体占多数。     

小兴安岭南坡野猪家域分析

采用笼式活捕野猪,利用无线电遥测技术、R2V、Arcview和SPSS软件技术,于2004年7月15日至2006年1月19日,对小兴安岭南坡野猪家域进行测定、计算和分析,以了解该地区野猪的家域变化规律.研究结果表明：季节变化影响野猪家域面积,在春、秋季,野猪的家域面积显著大于冬季,而春、夏季间无显著差异;不同性别及年龄野猪家域大小也不同,成体雄性秋季发情期和亚成体春季分窝期家域面积显著增加;在冬、春季家族群野猪的家域面积显著大于独体野猪家域面积,说明家族群对家域面积有影响;亚成体家域大小主要受家族群家域的影响,家族群野猪面积大,相应地家族野猪中亚成体家域面积也大.     

Modern Northern Domestic Horses Carry Mitochondrial DNA Similar to Przewalski’s Horse

Several recent studies have suggested past gene flow between the Przewalski’s horse and modern domestic horse and questioned the wild origin of the Przewalski’s horse. Mitochondrial DNA has placed representatives of the Przewalski’s horse into three among the eighteen haplogroups detected from the modern horse. Of these, two haplogroups have so far been found exclusively in the Przewalski’s horse, while the one shared with the domestic horse includes captive individuals that have uncertain pedigrees. We recently found five domestic horse individuals of North European horse breeds to carry a mitochondrial haplogroup that was previously confined only to the Przewalski’s horse. These individuals were sequenced for 6039 bp of mitochondrial DNA and used, together with domestic and Przewalski’s horse sequences presenting all horse haplogroups, to examine the phylogenetic relationships and to date the divergence time between Przewalski’s and domestic horse clusters within this haplogroup. The divergence was dated to have likely occurred about 13,300–11,400 years ago, which coincides with the time of the Younger Dryas.

     

Decision-Making in Przewalski Horses (Equus ferus przewalskii) is Driven by the Ecological Contexts of Collective Movements

We addressed decision-making processes in the collective movements of two groups of Przewalski horses ( Equus ferus przewalskii ) living in a semi free-ranging population. We investigated whether different patterns of group movement are related to certain ecological contexts (habitat use and group activity) and analysed the possible decision-making processes involved. We found two distinct patterns; 'single-bout' and 'multiple-bout' movements occurred in both study groups. The movements were defined by the occurrence of collective stops between bouts and differed by their duration, distance covered and ecological context. For both movements, we found that a preliminary period involving several horses occurred before departure. In single-bout movements, all group members rapidly joined the first moving horse, independently of the preliminary period. In multiple-bout movements, however, the joining process was longer; in particular when the number of decision-makers and their pre-departure behaviour before departure increased. Multiple-bout movements were more often used by horses to switch habitats and activities. This observation demonstrates that the horses need more time to resolve motivational conflicts before these departures. We conclude that decision-making in Przewalski horses is based on a shared consensus process driven by ecological determinants.     

Protamine P1 sequences in equids: comparison with even-toed animals

Protamine P1 amino acid sequences were determined from semen samples of the Przewalski horse, donkey, Somali wild ass, Grevy's zebra, and Grant's zebra (odd-toed perissodactyls), and compared with those of the domestic horse. Although the rate of amino acid variation of protamine P1 is known to be among the most rapidly diverging polypeptides, the equid sequences revealed only little variation. The sequence from the Przewalski horse was identical with that from the domestic horse. The other sequences differed from the corresponding sequences of the domestic and Przewalski horses in two positions-Ser29 was replaced by Cys and Gln32 was replaced by Arg. The presence of the Cys residue at position 29 in the protamine P1 from the zebras, the donkey, and the Somali wild ass may allow formation of one extra protamine disulfide bridge during chromosome condensation in these species. Comparison with protamines from various even-toed animals (artiodactyls) indicated amino acid changes specific for those but different from the equid sequences.     

A comparison of the mineral composition of milk of domestic and captive wild equids (Equus przewalski, E. zebra, E. burchelli, E. caballus, E. assinus)

Milk samples were obtained in early and/or late lactation from Przewalski horses, Hartmann's zebras, Grant's zebras, domestic horses, ponies and a mule mare made pregnant by embryo transfer. Samples were compared for their content of total solids, ash, calcium, phosphorus, magnesium, sodium, potassium, copper, zinc and iron. Milk from the Przewalski horses, Hartmann's zebra and the domestic horse had similar mineral composition and the content of minerals was higher in early than in late lactation. Milk from the domestic mule contained the lowest concentration of calcium, phosphorus and zinc but the highest concentration of magnesium, sodium and potassium. Milk from the Grant's zebras contained more sodium than potassium, unlike milk from Przewalski horses, Hartmann's zebras or domestic horses in which there was more potassium than sodium.     

Copy Number Variation in the Horse Genome

We constructed a 400K WG tiling oligoarray for the horse and applied it for the discovery of copy number variations (CNVs) in 38 normal horses of 16 diverse breeds, and the Przewalski horse. Probes on the array represented 18,763 autosomal and X-linked genes, and intergenic, sub-telomeric and chrY sequences. We identified 258 CNV regions (CNVRs) across all autosomes, chrX and chrUn, but not in chrY. CNVs comprised 1.3% of the horse genome with chr12 being most enriched. American Miniature horses had the highest and American Quarter Horses the lowest number of CNVs in relation to Thoroughbred reference. The Przewalski horse was similar to native ponies and draft breeds. The majority of CNVRs involved genes, while 20% were located in intergenic regions. Similar to previous studies in horses and other mammals, molecular functions of CNV-associated genes were predominantly in sensory perception, immunity and reproduction. The findings were integrated with previous studies to generate a composite genome-wide dataset of 1476 CNVRs. Of these, 301 CNVRs were shared between studies, while 1174 were novel and require further validation. Integrated data revealed that to date, 41 out of over 400 breeds of the domestic horse have been analyzed for CNVs, of which 11 new breeds were added in this study. Finally, the composite CNV dataset was applied in a pilot study for the discovery of CNVs in 6 horses with XY disorders of sexual development. A homozygous deletion involving AKR1C gene cluster in chr29 in two affected horses was considered possibly causative because of the known role of AKR1C genes in testicular androgen synthesis and sexual development. While the findings improve and integrate the knowledge of CNVs in horses, they also show that for effective discovery of variants of biomedical importance, more breeds and individuals need to be analyzed using comparable methodological approaches.     

Progressive und regressive Hirngrößienveränderungen bei Equiden

Progressive and regressive changes of brain size within Equidae From Hyracotherium to Equus brain size increased eightfold independently from body size. In domestication brain size is reduced; within mammals the amount of reduction depends on cephalization. Species with high cephalization show much more reductions than those with low cephalization. Among the ancestors of domesticated mammals wild horses have the highest cephalization level; reduction of brain size of more than 30% in domesticated horses could be expected. The size of the brain case of domesticated horses is only 14 % smaller than in wild Przewalski horses. We think that populations of the wild Przewalski horses have been crossbreeds between wild and domesticated animals. There is no difference in size of the brain case capacity and the brain weight between the Przewalski horses from zoological gardens and domesticated horses. This may be due to further crossbreeding between Zoo-Przewalski horses and domesticated horses and to artificial selection.     

Epidemiologic aspects of Taylorella equigenitalis

Contagious equine metritis (CEM) is a sexually transmissible disease in mares. Although the disease is commonly diagnosed by culturing the causative bacterium Taylorella equigenitalis (T. equigenitalis) . false negative results do occur. A recently developed Polymerase Chain Reaction (PCR) assay, however, appeared to be much more sensitive, with initial results indicating an unexpected high incidence of the agent in selected horses. In this study, samples from 107 randomly selected mares with no clinical signs of CEM submitted for conventional culture were all negative for T. equigenitalis . but in the PCR-assay 54 (49%) were positive for Taylorella -DNA. Positives in the PCR-assay were found in all breeds tested, even in horses imported from the isolated population in Iceland. These findings suggest that T. equigenitalis was present long before it was first isolated in 1977, The high incidence of Taylorella in horse populations without apparent clinical signs of CEM, the occurrence of incidental clinical case and the known variability between strains, all indicate that Taylorella is endemic in the horse population. In order to explore whether the organism is present in species other than the horse, we also used the PCR-assay on clinically health donkeys (n = 14), zebras (n = 15), Przewalski horses (n = 2) and cows (n = 21). All the animals showed negative results except one of the Przewalski horses, and one cow that was repeatedly found to give positive reaction. We also found that the fertility of 7 stallions with cultures positive for Taylorella (6 used in an AI-program and 1 by natural breeding) was not affected, as shown by the normal range of foaling rates in mares inseminated or bred by these stallions. The overall results may be interpreted to mean that Taylorella is of limited significance in horse breeding.     

Genetic characterization and population bottleneck in the Hucul horse based on microsatellite and mitochondrial data

The aim of this work was to gather information about the origin and genetic characterization of the Central European Hucul horse based on 71 horses using 17 microsatellites and the D‐loop region of mtDNA. Their genetic relationship to the Polish Konik (N = 7), German (N = 4) and Hungarian wild Przewalski horses (N = 4) and 200 horse sequences from GenBank was also analysed. Both microsatellite and mtDNA analysis showed a high genetic variation in the Hucul. A total of 130 alleles were detected, the mean number of observed alleles per microsatellite was 7.647, and the number of effective alleles was 4.401. The average observed and expected heterozygosity were 0.706 and 0.747, respectively. The high heterozygosity values and Wright's fixation index (F_IS) (?0.128) indicated a low level of inbreeding, low or no selection pressure, and large number of alleles. mtDNA analysis revealed 18 haplotypes for the Hucul population with a total of 23 variable sites. Haplotype and nucleotide diversities were 0.935 ± 0.011 and 0.022 ± 0.012, respectively. Neutrality tests (Tajima's D and Fu's Fs) were non‐significant, and mismatch distribution was ragged, indicating that the Hucul population is in genetic equilibrium. The most frequent mtDNA D‐loop region belonged to haplogroup A (48%), which was also present in Przewalski Wild horse samples, while Polish Konik samples belonged to three haplotypes and C, F, and G haplogroups. Large and significant pairwise Φ_ST values along with a small number of common haplotypes indicated a low level of gene flow and lack of genetic structure among the three studied breeds (Hucul, Konik, and Przewalski Wild horse). The present work contributes to our knowledge of the genetic diversity of the Hucul horse and helps to define its genetic conservation. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 54–65.     

Unicorn “holotype” skeleton from the Late Pleistocene spotted hyena den site Sewecken-Berge (Germany)

Late Pleistocene Ice Age spotted hyena remains are described from the “Unicorn holotype skeleton” gypsum karst site Quedlinburg-Sewecken-Berge, Germany (Central Europe). The hyena population consists of adolescent to late adult individuals (96% of hyena NISP; 15% of megafauna NISP) indicating a commuting den site type. The comparisons to other European bone assemblages support hunting specialization on woolly rhinoceros (19% of NISP) and horses (27% of NISP). Specialization on bovids (Bison/Bos) can be added for this site. The megafauna contain few Eemian warm period remains of a large horse Equus ferus fossilis. Most (95%) of the megafauna is attributed to the Late Pleistocene glacial (Weichselian/Wuermian). Horse bones are dominated by distal leg elements from the smaller Przewalski horses Equus ferus przewalskii (26% of NISP). The Unicorn “holotype” skeleton originates from a composed horse skull, vertebrae and front legs, whereas the elephant remains added to this biologically not valid species must have been a straight-tusked elephant tusk.     

Novel observation of play behaviour between a harem holder and a bachelor group of Przewalski’s horses in the wild

acta ethologica - Przewalski’s horses live in stable nonterritorial families (harem) of one or more harem stallions, several mares, and their offspring. The harem stallion typically behaves...