Factors influencing breeding success,ovarian cyclicity,and cub survival in zoo-managed tigers (Panthera tigris)

Understanding factors that influence reproduction and offspring survival in zoo populations is critical for management of threatened and endangered species. Examination of long-term data (1989–2011) compiled from the Association of Zoos and Aquarium's zoo-managed tiger breeding program provides the basis for a more thorough understanding of reproduction and scientifically based decisions for effective population management in this endangered felid. Biological and management-related factors that could influence tiger breeding success and cub survival were evaluated using logistic mixed models. Breeding success improved with female age until approximately age five, then declined thereafter. Experienced female breeders had greater breeding success than inexperienced females. Litter size was most predictive of cub survival, with average-sized litters (3–4 cubs) experiencing the highest proportional survival. Management-related factors, such as whether the breeding institution had a recent tiger litter and whether both animals were already located at the same institution, also influenced breeding success and cub survival. These results highlight the importance of institutional husbandry experience and the need to retain knowledge through staff turnovers to achieve optimal reproductive success. Using fecal estrogen data, frequency of ovarian cyclicity and mean cycle length did not differ by female age or parity; thus, lack of cyclicity and/or increased cycle duration are not likely explanations for declining breeding success with age. These results provide valuable reproductive information that should improve scientific management of zoo-based tiger populations.     

Technique for hand-rearing and reintroducing rejected cotton-top tamarin infants

During a one year period, seven rejected cotton-top tamarin infants were hand-reared. A hand-rearing program was developed which included the use of heated surrogates, a non-human primate infant formula, special nipples, and a systematic reintroduction into a family group. This regimen was quite successful. The hand-rearing process yielded a success rate of 75.0%, while the reintroduction process had a success rate of 80.0% for reintroduction into a family group and 100.0% survival rate.     

人工育幼非洲狮、孟加拉虎、豹幼仔的生长曲线拟合比较

<正>生长曲线(Growth curve)是揭示动物生长发育规律的有效手段之一，反映动物发育指标(包括体重、体尺、体表面积等度量值)与时间之间的关系(盛志廉和吴常信，1995)。生长曲线方程大致可以分为三类：第一类是表示报酬递减规律的方程，如指数函数；第二类是描述光滑S型曲线，     

A framework for assessing readiness for tiger <Emphasis Type="Italic">Panthera tigris</Emphasis> reintroduction: a case study from eastern Cambodia

Reintroduction is a viable conservation strategy for large carnivores however such reintroductions require robust feasibility assessments, considering ecological, management, and social factors, prior to implementation. Plans are being developed in a number of tiger range countries, including Cambodia, for tiger Panthera tigris reintroductions in response to local and national extinctions. We provide a framework for undertaking feasibility assessments for tiger, and other large carnivore, reintroductions and present a number of methodological tools, and appropriate indicators, for conducting such assessments. We apply the framework to plans by the Royal Government of Cambodia for tiger reintroduction into Srepok Wildlife Sanctuary (formally Mondulkiri Protected Forest), eastern Cambodia. Srepok Wildlife Sanctuary forms part of a large (>13,000-km²) trans-boundary conservation landscape with potential to support a tiger source population. Current ungulate prey densities, assessed through robust line-transect sampling, at approximately 5.0 individuals per km² may be sufficient to support a breeding tiger population. However levels of protected area management and law enforcement fall below global standards for tiger recovery. Local communities, though supportive of conservation efforts, also identified a number of concerns regarding reintroduction. Therefore current ecological, social, and management conditions within SWS are not currently suitable for tiger reintroduction. However with improved and more effective law enforcement, combined with robust monitoring of the indicators within our framework, such conditions could be met. We recommend that our framework for assessing landscape suitability for reintroductions offers an effective road map for reintroduction-based recovery of tiger populations across tiger range countries.     

Managing the socialization of an adult male gorilla (Gorilla gorilla gorilla) with a history of social deprivation

Most non‐human primates exhibit aggression during changes in social group composition. In zoological parks, group membership changes are necessary for optimal population management, but can elicit problematic aggression. Furthermore, some primates with a long history of social deprivation are hyperaggressive when introduced to conspecifics. In this study of one male gorilla with a 30‐year history of social deprivation, we assessed the rate of aggression quantitatively during a four‐step socialization procedure. We hypothesized that 1) the frequency of agonistic/display behaviors would increase markedly at the beginning of each phase of the socialization, then decline to baseline levels over time in each phase and 2) the frequency of affiliative behaviors would not vary systematically within or between phases of socialization. Our results largely supported these predictions, and we found the four‐step socialization process effective in managing aggression in this case. In addition to documenting the successful socialization of a socially deprived adult male gorilla, we believe that the empirical process used in this case argues for scientific management of other introductions. Zoo Biol 20:347–358, 2001. © 2001 Wiley‐Liss, Inc.     

Extralimital movements of reintroduced bison (<Emphasis Type="Italic">Bison bison</Emphasis>): implications for potential range expansion and human-wildlife conflict

Extralimital movements are of interest to ecologists and wildlife managers alike because they can be used to understand the ecological process of range establishment and to determine if management interventions are necessary. I summarize available information of 17 observations of extralimital movements of 23 bison (Bison bison) from two reintroduced populations in northwestern Canada, during 2000–2016. Distances recorded from the release sites and the centre of their range were 125–260 and 70–285 km, respectively. All observations were of adult (≥5 years old) males, and most (11 of 17) were of lone animals. Most (13 of 17) observations of extralimital bison were made during summer, ≥10 years after reintroduction. Results were similar for both populations. Four extralimital bison were killed by wildlife officials because of conflicts with agricultural interests; the fate of the others was unknown. These data point to the exploratory nature of reintroduced adult male bison during the summer, which may be a precursor to range expansion. Wildlife managers can monitor extralimital movements of reintroduced bison to identify potential areas of future range expansion or human-bison conflict. More generally, these observations may be useful to inform planning efforts for future reintroductions of bison.     

Male reunion displays in tufted capuchin monkeys (Cebus apella)

When males in captive tufted capuchin monkey (Cebus apella) groups separate and come together within their group, they have been observed to embrace and vocalize upon reunion. This display has not been observed in any other age/sex class. To investigate this, we deliberately separated six animals, including the only two adult males, from each of two social groups. We hypothesized that only the adult males would embrace upon reintroduction. When two males were consecutively reintroduced to their group, they typically ran to each other and came together in a frontal embrace, emitting stereotyped vocalizations. No other combination of animals showed this “reunion display.” Though dramatic, this behavior was in no way associated with incidents of aggression. We argue affiliative bonds may exist in these tufted capuchin male dyads. © 1996 Wiley-Liss, Inc.     

Hand-rearing reduces fear of humans in European starlings, Sturnus vulgaris

Pending changes in European legislation ban the use of wild-caught animals in research. This change is partly justified on the assumption that captive-breeding (or hand-rearing) increases welfare of captive animals because these practices result in animals with reduced fear of humans. However, there are few actual data on the long-term behavioural effects of captive-breeding in non-domestic species, and these are urgently needed in order to understand the welfare and scientific consequences of adopting this practice. We compared the response of hand-reared and wild-caught starlings to the presence of a human in the laboratory. During human presence, all birds increased their general locomotor activity but the wild-caught birds moved away from the human and were less active than the hand-reared birds. After the human departed, the wild-caught birds were slower to decrease their activity back towards baseline levels, and showed a dramatic increase in time at the periphery of the cage compared with the hand-reared birds. We interpret these data as showing evidence of a greater fear response in wild-caught birds with initial withdrawal followed by a subsequent rebound of prolonged attempts to escape the cage. We found no effects of environmental enrichment. However, birds in cages on low shelves were less active than birds on upper shelves, and showed a greater increase in the time spent at the periphery of their cages after the human departed, perhaps indicating that the lower cages were more stressful. In demonstrating reduced fear of humans in hand-reared birds, our results support one of the proposed welfare benefits of this practice, but without further data on the possible welfare costs of hand-rearing, it is not yet possible to reach a general conclusion about its net welfare impact. However, our results confirm a clear scientific impact of both hand-rearing and cage position at the behavioural level.     

Space Use,Survival, Movements,and Reproduction of Reintroduced Louisiana Black Bears

ABSTRACT Studies of reintroduced animals are beneficial to evaluate the success of reintroduction programs and to understand factors influencing fitness of reintroduced individuals. The geographic distribution of the federally threatened Louisiana black bear (Ursus americanus luteolus) has been reduced to 3 isolated populations due to habitat loss and excessive harvest. We reintroduced 23 adult female Louisiana black bears and their cubs to east-central Louisiana, USA, and documented postrelease space use, survival, movements, and reproduction. Individual females used larger home ranges after reintroduction than they had in the source population (P = 0.037). Spring ranges of reintroduced females were smaller than summer, autumn, and annual ranges (all P < 0.09), which did not differ from each other (all P > 0.60). Survival of reintroduced females did not differ between their first (S = 0.933) and second (S = 1.00) year after release or from annual survival of females in the source population (S = 0.964–1.00). Mean straight-line distance traveled by females from their release sites to the center of established home ranges or last recorded locations was 22.7 km. Six females reproduced after reintroduction and produced 15 cubs. Mean postrelease litter size of parturient reintroduced females (2.5) was similar to reported mean litter size of females in the source population (2.4). Our results suggest that the Louisiana reintroduction program is proceeding favorably; however, future studies should continue to monitor survival and reproduction of reintroduced females in Louisiana. Additional demographic parameters (i.e., cub survival) should be estimated to allow for population viability analysis to determine if the new population is self-sustaining.     

西藏墨脱格当乡野生虎捕食家畜现状与保护建议

曾经在西藏东南的阔叶林中广泛分布的孟加拉虎,目前仅有一个小种群残留在墨脱县境内。2000年5－6月间,在大型家畜遭受野生虎捕食最严重的墨脱县格当乡展开调查,试图寻找减轻虎害的方法。结果表明：1994－1995年虎的捕食率达到最高,对牛和骡马的捕食率分别是17．9％和9．4％;但1996年后,捕食率分别降低到7．8％和1．8％,这可能与1996年当地曾捕杀过一头虎有关。1993－1999年间,全乡牛的数量下降了11％,但骡马数量上升了23％,这是因为当地为增加运输能力而从别处购得骡马。据反映,目前格当乡境内大约有4－5头虎。1997年和1999年,均见母虎和小虎同行,说明该种群尚有繁殖。在抽样的21户居民家中,1999年4月到2000年5月间,66．6％的人家有大型牲畜遭虎捕杀,共损失牛27头,马12匹,而自1993年以来,21户中共有18户（85．8％）,有牲畜被杀记录,共计损失117头。其中对牛的捕食率达19．7％,对马达11．9％,平均每户损失牛1．2头,骡马0．5匹。非法狩猎减少了虎的猎物如野猪、羚牛等的数量,是老虎转向家畜的主要原因之一。虎害已对格当乡群众的经济造成较大负面影响。但格当乡以及周边地区保护着中国最后的野生孟加拉虎种群,为确保虎的长期生存同时减少人－虎冲突,建议改变目前放牧方式,尽可能联合放牧、增加看护;改善放牧地条件,清除牧场周围蕨草丛;减少对羚牛等有蹄类的猎杀,以减少对老虎猎物种群的破坏;对部分家畜移入棚内试行圈养,既保护家畜,又提高乳制品产量和增加农家肥料;实行多种经营方法,建议养一些山羊和家禽;政府应该帮助安置好部分愿意外迁的居民,这样既满足这些居民的需要,同时也减轻对当地野生动物种群的压力。     

中国野生东北虎数量监测方法有效性评估

虎数量监测是虎保护的核心内容之一。野生虎现存数量少、领域宽广,加之习性机警,很难对其数量和种群变化趋势做出准确的评估。合适的虎数量监测方法随着监测目标、监测尺度、虎密度、猎物密度、气候及其它环境因素的变化而不同。2002—2011年,用东北虎信息收集网络法,样线调查法,猎物生物量和捕食者关系法,对东北虎数量进行监测。(1)用老虎信息收集网络法研究2006年完达山东部地区东北虎的种群现状,结果显示东完达山地区2006年东北虎数量为6—9只,由1只成年雄虎,2—3只成年雌虎,2—4只亚成体虎和1只小于1岁的幼体虎组成;(2)用猎物生物量和捕食者关系法得到东完达山地区2002年东北虎的密度为0.356只/100 km2,能容纳22—27只东北虎;(3)用样线法在黑龙江的老爷岭南部和吉林省大龙岭北部面积1735.99 km2的区域内设置样线64条,总长609 km,没有发现东北虎足迹链。样线调查的结果表明,在2011年2—3月该调查区域东北虎的数量为0只。监测结果表明,用猎物生物量和捕食者关系得到东北虎数量远远超过现实数量,人们对有蹄类的盗猎和猎套对老虎的伤害可能是其主要原因;样线法调查得出的结果低于现实种群,主要原因是老虎数量极低和调查者对野生虎行为学了解甚少,较难在野外有效的发现虎信息;且样线法监测仅应用于当东北虎以一定的密度(即有定居虎)存在的情况下(多数监测样线能发现虎信息)。虽然和样线法一样存在着诸如专家估计密度和真实密度之间的关系,老虎足迹数量和老虎真实密度间关系不确定,保守估计等内在缺点,在目前中国东北地区野生东北虎种群密度极低,且多是穿越于中俄边境地区的游荡个体的现状下,信息收集网络法是一种高效,可行东北虎监测方法。因此,建议建立更广泛的监测信息收集网络,培训监测人员,严格执行信息收集程序,减少专家估计误差以完善此监测方法。此外,其他监测方法,如占有法、基于标志重捕远红外照相法、粪便DNA法、足迹数码信息法、警犬法等,应根据各种方法的理论前提、误差来源、适用范围和老虎是否定居及密度等具体情况有选择地加以应用,且有些方法可能成为未来中国野生东北虎种群的有效监测工具。     

The expression of aggression in old world monkeys

The expression of agonistic behavior in adult and juvenile members of both sexes was studied in groups of from 23 to 93 animals representing Macaca mulatta, M. arctoides, M. nemestrina, M. nigra, and Cercocebus atys. Data were collected using focal animal techniques over a period of 1 year for each group. Adult male biting was notably infrequent in all cases, and adult male participation in agonistic encounters was less frequent than for any other age-sex class, especially in the groups with the highest agonistic rates. Adult male agonistic behavior was often expressed as aggression but seldom involved contact forms of aggression, and biting constituted the smallest proportion of contact aggression for all age-sex classes. Adult males were also seldom the targets of aggression and had the highest rates for shaking of objects and bouncing displays. A tendency for the most severe forms of aggressive expression to be most frequent in those animals least capable of inflicting injury was noted in all groups, along with a tendency for aggression to be directed toward immature animals. Sex differences in aggressive expression and responses to aggression were noted, but the frequency of receipt of aggression was not directly reflected in the wounding noted. Different means to achieve the same consequence, infrequent adult male damaging attacks, are suggested to operate in the several groups studied.     

Ontogenetic changes and the stability of rhesus monkey dominance relationships

Dominance relationships were studied in a rhesus monkey group during five consecutive years. The group consisted of eight stable matriarchies and an adult male class which was replaced at the start, and again at the midpoint, of the study. Immature males were selectively harvested to maintain a sex ratio typical of natural troops. Maximum group size during the study was 77 animals.Dominance relationships were remarkably stable, with only 4.4% of dyads failing to show unidirectional relationships. Despite this stability, a linear ranking of all group members was not possible. Male dominance relationships with other males were among the most stable, following the fighting which ensued on male introductions. Male introductions did not disrupt female dominance relationships.Adult female dominance relationships were also quite stable, but immature females slowly achieved dominance over older sisters and females subordinate to their mothers. Such reversals were the result of processes lasting over many months. Many dominance assertions occurred prior to puberty but a significant number occurred following sexual maturity. Maturing females did not reverse dominance relationships according to any particular hierarchial order and, as a consequence, many were subordinate to animals that were dominated by others that they dominated.Although there was an alpha male that was dominant to all animals in the group, adult females dominated most adult males. Adult males, however, often reciprocated aggression directed at them. They almost invariably threatened or countercharged aggressive immature animals regardless of matriarchial membership. Adult males dominated some adult and most young females, even in families containing matriarchs and adult females to which the adult males always submitted.The dominance relationships of young males were similar to those of their sisters, until puberty. Young males did not necessarily bypass adult males that their mothers outranked, and often failed to win against adult females that their mothers dominated. Adolescent female aggression against females is seldom interfered with by adult males, and females may actively aid one another against males. In contrast, the aggression of young males often elicits interference by adult males, and young males often become the targets of redirected aggression in the group. As a consequence, whereas young females rise in rank to positions adjacent to their mothers, adolescent males often suffer losses to animals that they had dominated as juveniles.     

Ecological correlates of lion social organization (Panthers, leo)

Data on lion home range size, pride size, density, group size, cub survival, litter size and adult sex ratio were extracted from studies carried out in 10 habitats. The data were compared with five measures of food supply: mean prey biomass, prey biomass during the season of greatest abundance, prey biomass during the season of least abundance, biomass of middle-sized prey species (i.e. those with mean adult live-weights between 50 and 250 kg), and the mean size of carcasses fed on by lions. The results indicated that range size is inversely correlated with the abundance of prey during the period of least abundance, but not with overall prey abundance. Range size showed no consistent variation with pride size or with minimum metabolic requirements. Pride size (measured in terms of average number of animals per pride and average number of adult females) and cub survival strongly correlated with lean season food abundance. No relationship was found between group size or litter size and any of the measures of food supply Adult sex ratio did not vary consistently with food supply or lion density, although the data did suggest that prides inhabiting small, circumscribed reserves may experience less inter-male competition and this, in turn, may affect the adult sex ratio.     

Long‐term monitoring of social behavior in a grouping of six female tigers (Panthera tigris)

Although literature on the reproduction of captive tigers is plentiful, there is little information on other social behaviors, particularly within large social groupings. Here we report on the long‐term monitoring of social behaviors in six female tigers (Panthera tigris). Over a period of 6 years, behavioral data were collected on spraying, vocalizations, non‐contact aggression, and contact aggression during outdoor observations, as well as nearest neighbors in the morning, as a proxy measure of affiliation. Regression analyses showed that non‐contact aggression and vocalizing were increasing, whereas spraying and social proximity were decreasing over the 6 years of the study. Paired t‐tests showed no seasonal differences in aggression, but animals had higher social proximity scores during the mornings of the colder winter months. Correlations showed that spraying was positively related to contact aggression whereas social proximity was negatively correlated with non‐contact aggression. In addition to documenting levels of contact and non‐contact aggression over time, this study showed these behaviors correlated with behaviors that were more easily scored (spraying and social proximity). Behavioral monitoring has played a key role in the management and husbandry of this large social grouping of female tigers. In addition to providing keepers with the opportunity to observe their animals in regularly scheduled sessions, behavioral monitoring has provided baseline information on social relationships in this grouping over time. If future research validates the relationship between aggression and spraying/social proximity, this can be a valuable tool for long‐term monitoring of groups of tigers. Zoo Biol 27:89–99, 2008. © 2007 Wiley‐Liss, Inc.     

Integrative focus on dynamic motor patterns and age hierarchy in the expression of aggression

In this study, we analyzed the dynamic motor patterns of attack or defense and age hierarchy to investigate aggression in African mole-rats Cryptomys foxi and the house mouse Mus musculus. The objective is to verify if the social order of dominance is associated with age hierarchy within the social group. Using the resident-intruder experimental model, we created a series of dyadic encounters that comprised of a standard adult mouse or rat paired with groups of aggressive and hierarchically age-ranked small animals in a territorial aggression test. Our results indicate that though the adult animals displayed the highest level of aggression, indicating their dominant status, there was no age-related hierarchical formation in the expression of aggression. In the non-territorial aggression test in which rats or mice were grouped together, animals displayed low levels of aggression compared to the territorial test and no hierarchical age-related order. These results indicate that the magnitude of aggression expressed by animals in the social group, based on their motor patterns of attack and defense, seem to depend on individual competitive strategies in reaction to various environmental challenges and not necessarily on age hierarchy.     

Impaired reconciliation in rhesus macaques with a history of early weaning and disturbed socialization

An attempt had been made to create five social groups from rhesus macaques with a history of early separation from their mothers, early weaning and hand feeding and, in most cases, previous housing in single cages. We investigated the exchange of affiliative behaviours after an aggressive encounter and selective attraction to the former opponent, a phenomenon previously well described in rhesus monkeys and called reconciliation. Evidence for reconciliation was only found in one of the five groups studied (corrected conciliatory tendency=13%). This group consisted of younger animals that had, at least temporarily, been living together after separation from their mothers. In the other groups studied, containing animals with a varied background, aggressive interactions were not followed by affiliative behaviours or attraction between former opponents. Our results indicate that the use of reconciliatory behaviours in adult monkeys is dependent upon social training. Lack of functional reconciliation might be one of the explanations to the severe and uncontrolled aggression previously found in groups of rhesus macaques created from animals with disturbed early socialization.     

What defines successful integration into a social group for hand-reared chimpanzee infants?

Hand-rearing of captive great ape infants is sometimes necessary but can have negative behavioral consequences. Modern hand-rearing protocols, including early integration into a diverse group of conspecifics, appear to reduce the negative consequences of hand-rearing, but the process of integration is not well studied. We investigated six potential metrics of success during the introduction of two hand-reared chimpanzee infants into a troop of nine other chimpanzees at the Maryland Zoo in Baltimore. Little aggression was observed and the infants continue to be maintained in the troop at publication. As we predicted, during the introduction the hand-reared infants showed consistent levels of stress-related behaviors, participated in affiliative interactions with all available partners, and acted, received, and mutually engaged in these interactions. Solitary behaviors by these infants were similar to a mother-reared infant in the same group. Each infant also formed a relationship with a specific female that involved nest-sharing, carrying, retrieval, and intervening to reduce risk to the infant; these relationships could be classified as allomothering because they involved maternal behavior but occupied significantly less of the infants’ time than a maternal relationship. Contrary to our prediction, the hand-reared infants therefore spent significantly less time in social behavior than a mother-reared infant of the same age. In addition, the hand-reared infants continued to show strong social preferences for each other as introductions progressed and to direct a low but consistent number of nonfeeding social behaviors to humans. The successful introduction of hand-reared infants appeared to involve adding conspecific social relationships to the infants’ social repertoire, but not eliminating social interactions directed at humans.