大熊猫取食时的利手研究

利手现象广泛存在于人类和非人灵长类动物,以往曾开展了深入的研究工作.然而,针对灵长类以外的物种,尤其是珍稀濒危物种是否存在利手,未曾有过报道.以我国珍稀濒危物种大熊猫为研究对象,通过行为观察法,首次对其利手现象进行了系统研究.结果发现大熊猫在个体水平存在利手现象,但是在群体水平不存在明显的一侧利手优势.雄性个体的利手指数与其年龄呈现显著的负相关关系(r=-0.590,P=0.008,N=19),即幼年雄性个体多表现为左利手,成年和老年雄性多表现为右利手.雌性不存在类似的相关关系(r=0.219,P=0.245,N=30).相对单一的食性和取食、活动及育幼方式,可能是影响大熊猫利手指数的主要原因.     

秦岭川金丝猴的一次家庭雄性替代

家庭雄性替代已在亚洲叶猴的许多种类中有所报道。 2 0 0 3年 ,我们在一种亚洲叶猴———秦岭的川金丝猴 (Rhinopithecusroxellana)的一个单雄家庭中观察到一次完整的家庭雄性替代过程。此次替代发生于 4月 2 8日 - 5月 2日的五天时间内。在家庭雄性发生替代后的第六个月 ,该家庭中的婴猴消失。本文是首次对野生川金丝猴家庭雄性替代进行详细的报道。通过本次观察证明野生川金丝猴的确存在家庭雄性替代的现象。且像亚洲叶猴的许多种类一样 ,野生川金丝猴的家庭雄性替代同样发生于产仔季节和交配季节之间。但我们仍无法确定在本次雄性替代中婴猴最终的消失是否是雄性杀婴的结果     

金丝猴(RHINOPITHECUS)脑的外部形态

本文是对三种金丝猴脑的外部形态的观察结果表明:金丝猴的大脑皮层除存在猴科固有的全部沟裂外,还较其他猴科动物具有更多的副沟。大脑的沟型与疣猴亚科的特征完全吻合,但是很多特点都较叶猴更近似于长臂猿。另外,除了蚓叶和蚓结节较小,四叠体的下丘较猕猴发达以外,金丝猴的小脑和脑干均与猴科的一般特征无明显差异。     

人工饲养下金丝猴繁殖的观察研究 Ⅰ.交配行为

金丝猴(Rhinopithecus roxellanae)是我国稀有的珍贵特产动物,笔者在多年观察金丝猴的繁殖行为的基础上,又于1986年8-9月在北京动物园,对金丝猴的交配、爬跨行为进行了专门观察,发现金丝猴发动性活动的一些特点,并在交配爬跨时,雄性金丝猴有卷尾现象。其交配行为与叶猴和猕猴有差异。     

反捕食不能充分解释獐的集群行为(英文)

我在江西鄱阳湖国家自然保护区研究了獐 (Hydropotesinermis)的集群行为并检验了集群是动物反捕食对策的假说。如果这个假说成立 ,我们则可以做三个预测 :(1)集群大小应与植物覆盖度成负相关 ;(2 )集群动物比单独活动的动物有更多的时间取食 ;(3)集群动物与单独活动的动物相比 ,用于警戒的时间较少。结果表明 ,獐的集群在交配季节最大而在产仔季节最小 ,獐在短草期比在高草期倾向于形成较大集群。因此 ,本研究支持了第一个预测。但是 ,集群的獐和单独活动的獐在取食和警戒时间分配上并无差异。因此 ,本研究不支持第二和第三个预测。时间收支 (timebudget)分析显示 ,在非交配季节 ,带幼仔的雌性用于取食的时间较少但走动频繁。在交配季节 ,与单独活动的雌性相比 ,与雄性在一起的雌性用于取食的时间较少 ,而单独活动的雄性却比与雌性在一起的雄性花较多的时间用于观望寻找雌性。鉴于獐集群行为的复杂性 ,本研究认为 ,獐并不只因反捕食而集群 ,其它社会和生态因子在决定獐的集群行为中也很重要。     

金丝猴(RHINOPITHECUS)肌肉系统某些特征的比较研究

本文对金丝猴与其他灵长类之间和三种金丝猴之间特征不同的56条肌作了比较研究。结果表明:三种金丝猴的肌肉系统存在一些差异。纠正了Patterson(1942)对一例川金丝猴的一些错误观察记录。在金丝猴属的肌学方面除与猴超科共有的大部分特征外,还具有与类人猿和人相似的特征。在猴类中,金丝猴的肌肉系统更多地与叶猴相似,其中一些特征较叶猴更为进化。从进化观点看,金丝猴的肌学特征似介于叶猴与类人猿之间,故它们比其他猴超科动物更为进化。     

行为生态学(十五):动物的领域行为(2)

(2)无资源领域——求偶场有时,雄性动物既不保卫雌性动物,也不竞争雌性动物所需要的资源。这或许是因为资源过剩或资源的时空分布难以预测,或许是因为雄性动物为此需要付出的代价太大。在这种情况下,雄性动物往往聚集在一个传统的公共场地,各自占有一小块领域,并以自己的显示行为争取把雌性动物吸引到自己身边来。这种雄性动物求偶时聚集的场地就叫作求偶场     

金丝猴(Rhinopithecus)的某些结构特征

本文在对金丝猴的三个种群作系统解剖的基础上,与其他灵长类以及金丝猴的三个种群之间进行了比较。结果表明:在金丝猴与其他灵长类进行比较的44个项目中,金丝猴特有者9项;与叶猴相同而与其他灵长类不同者4项;与疣猴类的共同特征9项;与叶猴、类人猿和人相似而为其他猴类所不具备的特征有5项;与类人猿和人相似而为叶猴和其他猴类所不具备的特征有17项。因此,我们认为金丝猴的地位在叶猴之上,是猴超科(Cercopithecoidea) 中最进化的一个属,在灵长类系统发育中处于猴类与猿类之间的中间地位。在金丝猴三个种群之间互异比较中,相互不同的特征均超过60％,似乎完全有理由把它分立为三个种。     

关于白头叶猴分类地位的探讨

通过一只雄性白头叶猴与一只雌性黑叶猴杂交繁殖的F1代(雌体)与黑叶猴(雄体)的回交,成功繁殖出两只回交代个体,出生后两回交代个体健康状况良好,所显露出来的形态学特征介于亲本之间,没有呈现明显的分化现象。杂交代的成功繁殖表明白头叶猴与黑叶猴不存在生殖隔离。从而断定白头叶猴不是一个独立种,而是黑叶猴的一个亚种。     

中国长臂猿的分布(英文)

中国南部分布着3种长臂猿,它们是白眉长臂猿(Hylobates hoolock)、白掌长臂猿(H.lar)和黑冠长臂猿(H.concolor)。黑冠长臂猿在我国境内有3个亚种:指名亚种(H.c.concolor),白颊亚种(H.c.leucogenys)和海南亚种(H.c.hainanus)。这些种类目前只分布在云南和广东的海南岛,但在五十年代初也生活在广西的西南部。这些地区是长臂猿属分布区的东北边界。 同它们在中南半岛的地理特征相一致,中国的3种长臂猿的分布区不相重迭,以两条大江为界。白眉长臂猿栖居在云南怒江以西,白掌长臂猿生活在怒江与澜沧江之间地带,黑冠长臂猿占据澜沧江以东。但是有一处,即黑冠长臂猿的云南保山瓦窑分布点例外,该地的标本收藏在动物研究所。 对于黑冠长臂猿海南亚种的文献记述存在不确切之处。现有较多的标本表明,海南亚种的雌性个体头冠部具有界限明显的黑色大斑块;成年雌性个体背毛呈浅棕灰色或较鲜亮的赭黄色;背中部毛较长,在40—75毫米之间。 我们所研究的标本收藏在以下单位:纽约美国自然历史博物馆,北京自然博物馆,芝加哥福地自然历史博物馆,复旦大学生物系,中国科学院动物研究所,广州华南濒危动物研究所,上海自然博物馆,上海动物园(活体),中山大学生物系。     

Heterochely and handedness in the shore crab Carcinus maenas (L.) (Crustacea: Brachyura)

A large sample ofadult male Carcinus maenas was 79% right-handed and 21% left-handed. A separate sample of 207 intact adult males was divided into left-handed and right-handed crabs and four measurements were taken from all major and minor chelae. Correlation and regression analyses against carapace width on log-transformed data showed that major chelae of right-handed crabs grow proportionately higher with increasing size and the ideal mechanical advantage increases; concurrently, the fingers of the minor chelae grow proportionately longer. The data for left-handed crabs showed greater variability, especially for minor chelae, providing evidence for the concept that left-handedness arises by reversal of handedness following loss of the major chela from the right-hand side. Records of handedness in large samples of non-ocypodid heterochelous brachyuran crabs show a preponderance of right-handedness.     

Handedness in the common marmoset (Callithrix jacchus)

For about 20 months the development of hand preferences in 21 experimentally naive common marmosets (Callithrix jacchus) was examined in 15 different tests. Test preferences were compared with their spontaneous behavior preferences in such contexts as feeding, grooming, play, and others. In the spontaneous use of the hands, only eight animals showed a significant lateral preference (2 left-handed, 6 right-handed). During the test period, however, the number of handed marmosets increased to 19 (5 left-handed, 14 right-handed). Most of the animals fluctuated considerably in their preference levels, a situation which led to a remarkable test response inconsistency of handedness. When the test situation was changed, complete reversals of handedness were more frequent than weakening or strengthening of a particular preference. The animals' emotions during the test session and environmental variables affected handedness significantly. None of the tested marmosets showed an increase of hand preference from the first to the last test. Our results indicate that Callithrix is ambidextrous rather than handed.     

Sex difference in chimpanzee handedness

Chimpanzees at Mahale, Tanzania, show strong individual hand preferences when they use bimanual actions in processing the fruit of Saba florida and Citrus lemon. The direction of hand preference differs between the sexes: most males are left-handed, whereas most females are right-handed. Monkeys and apes are considered to lack "handedness," in the sense of a population mode of left- or right-hand preference; they are normally ambidextrous. Indeed, strong individual preferences were previously seldom found in natural tasks. We propose that lateralization of manual actions becomes advantageous in bimanual tasks, which involve role differentiation between the hands and a need to combine power and precision. If the pattern of lateralization found here reflects the ancestral state, common to chimpanzees and humans, this may explain why, in modern humans, women tend more strongly to be right-handed than men, who include a larger minority of left-handers.     

Nature of functional motor asymmetry in animals: state of the problem

Handedness in skilled movements of animals is a result of interaction of innate motor preference and learning. The nature of the innate preference is not clear. Breeding of right-handed and left-handed mice revealed that the degree rather than direction of motor preference is an inherited feature. There is, however, a correlation between the direction of preference and a number of morphological, functional, and neurochemical characters. Shifts of a preference direction were found in some strains of mice. Differences between right-handed and left-handed rats were revealed in social behavior, learning, and resistance to forced retraining. Strains of rats with different forms of genetic epilepsy were characterized by the predominance of animals with a certain direction of the motor preference. This evidence suggests some genetic influence on a direction of the motor preference. Perhaps, genetic and environmental factors closely interact in determining motor preference in animals.     

The role of individual characteristics and learning in the manifestation of motor asymmetry in rats

Relative role was studied of the "initial" preference (caused by animals individual properties) and learning in real preference of one limb in rats. After a short-time learning to get food from a narrow horizontal pipe only by the left paw a retrograde amnesia was evoked in rats. At preference determination after three weeks, in conditions which allowed to get food by any paw, in the group of animals without amnesia the number of the left-handed rats was 5.7 times more than of the right-handed ones. In the group of animals with amnesia the numbers of the left-handed, right-handed and ambidextrous were approximately equal. Correlation was revealed between the speed of learning to get food by the left paw and the number of attempts to use the right paw. It has been shown that the initial preference may be stably changed even by a short-time learning (3 food seizures). By the degree of manifestation of the initial preference the rats form a continuum with a gradual transition from pronounced right-handed animals to pronounced left-handed ones. The weaker is the initial preference, the greater the role of learning in the real preference of one of the paws.     

Different recovery of a skilled movement after destruction of the caudate nucleus in rats with right- or left-forelimb preference]

Recovery of the motor skill of taking a sunflower seed from a tube after the electrolytic destruction of the caudate nucleus was studied in Wistar rats with left- (n = 27) and right-forelimb (n = 22) preference. The reaching performance was divided in 5 stages. The first two stages characterize the emotional condition of an animal, the following three were immediately related with the skilled movement. After preliminary testing, the head of the caudate nucleus contralateral to the preferred limb was electrolytically damaged. After surgery, rats were tested during 20 weeks, and in every test the following indices were measured: percent of rats which perform the movement characteristic for the given stage, stage duration, depth of reaching a flower seed from the tube, time necessary to obtain the best results etc. It was found that at the "emotional" stages, higher percent of the right-handed animals perform the characteristic movements, but they spend more time to complete these stages than the left-handed rats. In rats with the left-limb dominance the recovery of the specialized movement is positively correlated with the time of the recovery onset at all the stages, while there is no such correlation in rats with right-limb dominance. Both groups of animals reach the same depth of the tube in the course of recovery, but the left-handed rats attain these results later and gradually, while the right-handed animals attain the maximal extent of recovery spontaneously and earlier than left-handed ones.     

Motor skill recovery in rats with various forelimb preference subjected to lesions in the caudate nucleus

Rats were trained for retrieving a sunflower seed from a tube using a forelimb. In the process of training, all the animals were divided in two groups: with the right- and left-limb preference. The period of learning was divided in two emotional (after the period of anxiety the animal takes a sunflower seed from the flow of a chamber) and three motor stages (different degrees of dexterity and precision in reaching a seed in the tube and grasping it). After a rat learned the skilled movement, the caudate nucleus was lesioned contralaterally to the preferred limb. After surgery, the animals were tested for recovery of the motor skill. The stages of recovery were the same as during learning. "Right-" and "left-handed" rats were compared in the percentage of animals performing each stage, duration of each stage, the depth of the tube reached by the animal's forelimb, and time required for obtaining the best results. The "right-handed" rats dominated in the percentage of animals performing the emotional stages and later began to recover the skilled movement (the crucial motor stage) but faster acquired their individual maximal depth of reaching a seed in the tube than the "left-handed" animals. The recovery of the skilled movement in the "left-handed" animals was a more gradual process than that in the "right-handed" ones.     

Influence of the task on hand preference: individual differences among gorillas (Gorilla gorilla gorilla)

The degree of task complexity and bimanual complementarity have been proposed as factors affecting lateralization strength in humans. However, a large number of studies have demonstrated group-level lateral hand bias for different manual activities in numerous non-human primate species. However, no study has tested the effects that a variety of tasks may have in inducing differences in hand preference. Here, we aim to test if 3 adult gorillas exhibited a greater hand preference bias performing 4 tasks of varying complexity: grasping small versus large foods, proto-tool use task and tool use task involving greater visuospatial requirements. We found that (1) the complexity of the task does not necessarily induce a right-handed bias and (2) a subject can be right-handed for a complex task and left-handed for another one. These results, complemented by many publications on hand preference in non-human primates, reveal a great variability in hand preference, which makes it very difficult to deduce any details of hominin handedness with artefacts.     

On the handedness of Japanese monkeys

Forty-one monkeys living on the Koshima Island were tested for handedness by throwing a peanut 10 or 20 times toward each subject and recording which hand was used to pick it up. Handedness was judged at the 5% level of confidence. Animals showing no preference for the left or right hand after 20 trials were considered to be ambidextrous. The following distribution of handedness was found: left-handed, 17 (41%); right-handed, 8 (20%); ambidextrous, 16 (39%). These findings were compared with other studies on the handedness of Japanese monkeys. Handed monkeys outnumber the ambidextrous ones and the left-handed monkeys outnumber the right-handed ones. The characteristic distribution of handedness was shown to be irrespective of troop. By looking over the data from these different sources, the proportions of the left-handed, the ambidextrous, and the right-handed in Japanese monkeys were estimated at 39%, 33%, and 28% respectively. The method used in this study was compared withKawai's catching behavior and reasons for disagreement between judgments of handedness were discussed.     

Handedness found in a wild group of moor monkeys Macaca maurus in the Karaenta Nature Reserve, South Sulawesi,Indonesia

Hand preference of wild moor monkeys Macaca maurus was investigated in food reaching situations at the Karaenta Nature Reserve, South Sulawesi, Indonesia. The frequency picking up sweet-corn grains to take into the mouth by either hand of monkeys was counted directly at the feeding ground where sweet-corn grains were scattered for monkeys. Among the 20 monkeys examined, 8 were fight-handed, 8 were left-handed, and 4 were ambilateral. The results indicated the prevailed hand preference on individual level but not either trends of left- or right-hand preference on population level. The trend toward a higher proportion of left-handed monkeys found in Japanese and rhesus monkeys was not found. Some other characteristics found in moor monkeys are discussed in comparison with those previous findings in Japanese and Tibetan macaques in order to evaluate variations within the genus Macaca.