Allocare in a nocturnal primate: data on the spectral tarsier, Tarsius spectrum

Non-maternal infant care in many of the small-bodied New World primate species has been hypothesized by some researchers to be related to the high infant/adult weight ratio found in these species. The spectral tarsier, Tarsius spectrum, an Old World primate, has one of the highest infant/adult weight ratios of any primate, with infants weighing between 20-33% of adult weight at birth. On the basis of the hypothesized relationship between allocare and the infant/adult weight ratio, it is predicted that the spectral tarsier will also exhibit extensive allocaretaking behaviour. The results of this study indicate that although spectral tarsiers show care by male and female subadults as well as adult males, it is extremely limited compared to the extensive allocaretaking behavior observed in New World primate species such as Aotus and Callicebus. Spectral tarsier subadult females provide substantially more allocare to infants than do subadult males or adult males. Female subadults were observed sharing food, transporting, grooming, playing, alarm calling, baby-sitting and maintaining physical contact with infants more than other age/sex classes. Although the amount of allocare exhibited by adult males and subadult males was much less than that exhibited by female subadults, the data suggest that adult and subadult male spectral tarsiers do play a small part in the care and socialization of the infant. Adult males and subadult males were both observed occasionally engaging in allocaretaking behaviors such as grooming and playing, as well as frequently patrolling and defending the territory's boundaries. The results from this study suggest that although a high infant/adult weight ratio may be a prerequisite for selection to favor extensive allocare, it is not a causal factor. Additional research is needed in order to understand better the selective pressures involved and the costs and benefits of providing allocare to subadults and adult male spectral tarsiers.     

Social behaviour and infant carrying in a group of moustached tamarins,Saguinus mystax (primates: Platyrrhini: Callitrichidae), on Padre Isla,Peruvian Amazonia

The social behaviour of a group of eight moustached tamarins,Saguinus mystax, (five males, three females) was studied on Padre Isla in northeastern Peru. About 60% of all allogrooming was done by the two adult males in the group, and about 11% by a young adult female. All other group members groomed very little. The adult breeding female received more grooming than any other group member. After the death of the adult female (preyed upon by an anaconda) the amount of active allogrooming remained constant for all group members except for the young adult female, who increased her contribution to about 30%. Her preferred grooming partner was the subadult female, which generally screamed when being groomed by the young adult female and terminated grooming by going away. This kind of grooming relation is termed “forced grooming” and is interpreted as a possible social control mechanism. The young adult female groomed the adult males more often after the death of the adult female than before. This might have had the function of strengthening the social bond with the adult males and in obtaining the breeding position in the group. After the death of the adult female, the vulva of the young adult female grew to full adult size. Agonistic behaviour was less frequent than allogrooming. Most aggressive interactions (50%) originated from the subadult male of the group. The young adult female was the target of most of these aggressions. Extremely little aggression occurred between the three females. The young adult female was the only individual who tried to emigrate from the group during the study period. Her attempt to join a neighbour group failed due to rejection by all four members of this group. All group members participated in carrying an infant, but the adult males and the young adult female carried most frequently. Contribution to infant carrying varied with the infant's age.     

Impact of male takeover on intra-unit sexual interactions and subsequent interbirth interval in wild Rhinopithecus roxellana

Data were collected on sexual interactions before and after a male takeover of a one-male unit (OMU) of Sichuan snub-nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains, China. The original unit consisted of an adult male, 2 adult and 2 subadult females, 2 female juveniles and a single infant. Following the takeover, the new resident male copulated with 1 adult female, which was not lactating. Subsequent to the disappearance of her infant, the second (lactating female) entered breeding condition and began to solicit copulation with the new resident male. The subadult females also engaged in matings with the new male. The new resident male was observed mating, on 3 occasions, with females in 2 other OMUs. These are the first observations of sexual behaviour in free-ranging Sichuan snub-nosed monkeys after an OMU takeover. Sexual interactions play an important role in establishing relationships between the new male and resident females in the OMU.     

Use of time and space by platypus (Ornithorhynchus anatinus: Monotremata) along a Victorian stream

Radio-tracking and mark recapture methods were used to characterize the spatial organization and temporal activity patterns of free-ranging platypuses in southern Victoria. The study area supported an estimated 1.3-2.1 adult or subadult animals per kilometre of stream in the three summers sampled. The individual home ranges of 15 radio-tagged animals comprised 0.33-2.28 km of stream; animals foraging exclusively in the stream had significantly longer ranges (mean=1.40 km) than animals which also foraged in associated pond habitats (mean=0.64km). Home ranges of grown females overlapped with those of neighbouring grown females, subadult and adult males, and juveniles (相似文献   

Female transfer between one-male groups of proboscis monkey (<Emphasis Type="Italic">Nasalis larvatus</Emphasis>)

Successful or unsuccessful female transfers were observed seven times during a 32-month field study of proboscis monkeys (Nasalis larvatus) inhabiting a riverine forest along a tributary of the Kinabatangan River, Sabah, Malaysia. In all cases, the females voluntarily left their own groups and immediately joined with another one. When adult females tried to shift to other groups, adult males called them back to their own groups, but appeared to be indifferent to subadult females. When the adult females returned, the males never attacked the females physically, but instead often emitted herding sounds to them. One subadult female was repelled by a resident adult female. When one adult female transferred into a new one-male group, she left her behind son in an all-male group. The number of females often fluctuated in most study groups, with this fluctuation being more prominent among subadult females than adult females. It is likely that female transfer in proboscis monkeys is not a rare occurrence and that it is especially common among sub-adult females.     

Observations on infant sharing in captiveColobus polykomos

The behavior of two female and two maleColobus polykomos after the birth of a baby into a zoo exhibit was recorded and then analyzed. Infant sharing was observed between the mother and the subadult female. Initially transfers of the baby were traumatic, but as the day progressed the transfers became more amicable. The subadult female was not allowed to handle the baby while it was nursing and this was monitored, in large part, by one of the adult males. Although transfers were frequent between the two females, neither male was observed to hold the baby until it was four weeks old. There was a marked discrepancy in the ability of the females to handle the infant and this is discussed in light of some observations made on chimpanzee mothers in the wild.     

Patterns of infant handling and relatedness in Barbary macaques (<Emphasis Type="Italic">Macaca sylvanus</Emphasis>) on Gibraltar

Among papionin primates, the Barbary macaque (Macaca sylvanus) shows the most extensive interactions between infants and group members other than the mother. Two different types of interactions occur: (1) long-lasting dyadic interactions between a handler and an infant, and (2) brief triadic interactions between two handlers involving an infant. Previous investigations showed that infant handling by males is best explained as use of infants to manage relationships with other males. In contrast, no adaptive explanation for infant handling by females emerged. Here, we compared the infant-handling pattern between subadult/adult males and subadult/adult females in a free-ranging group of 46 Barbary macaques on Gibraltar to test whether the relationship management hypothesis also applies to female handlers. We further investigated the infant-handling pattern of juveniles and used microsatellite markers to estimate relatedness between infant handlers and the infant’s mother. We found that males, females and juveniles all participated extensively in triadic interactions using infants of above-average related females. In contrast, only males and juveniles were highly involved in dyadic interactions with infants of related females, while females rarely handled infants other than their own. The pattern of infant handling was entirely compatible with the predictions of the relationship management hypothesis for males and mostly so for females. Moreover, our genetic analysis revealed that males and females differ in their partner choice: while females preferred to interact with related females, males had no significant preference to interact with related males. We further discuss the observed above-average relatedness values between infant handlers and the infant’s mother in the light of kin-selection theory.     

Male replacement and stability of territorial boundary in a group of agile gibbons (Hylobates agilis agilis) in West Sumatra, Indonesia

We report membership change in a group of wild agile gibbons, Hylobates agilis agilis, in West Sumatra, Indonesia. During 6-month observational periods, we focused on a particular unit of individuals known as the B group. We confirmed that the group consisted of five individuals: one adult female, one adult male, one subadult male, one subadult female, and one infant male. During our observations, the resident adult male and the two subadult individuals dispersed or disappeared, and a new adult male took over the group. We examined the effects of the male replacement on the territorial boundary, using the auditory census technique. The boundary was stable. We also documented the succession of the home range. Our results indicate a flexible social structure in this species and contribute some useful data to an ongoing debate on their social dynamics.     

Spacing system of the Mysore slender loris (Loris lydekkerianus lydekkerianus)

Loris lydekkerianus lydekkerianus has been shown to have a promiscuous copulatory pattern, to maintain social networks via frequent loud calls, to interact socially throughout the night with all age classes, and to sleep socially. Though these behaviors point towards a multimale social system, no study of their spacing system has yet been provided to support this view. From October 1997-August 1998, I conducted a study of the Mysore slender loris in Ayyalur, India. During 1,400 field hours, data were collected on range use of 3 adult females, 3 adult males, 1 subadult female, and 1 subadult male. Lorises slept in groups averaging 4 individuals, composed of an adult female, her offspring, and 1-2 adult and subadult males. Sleeping sites for three groups were located within 1.9 ha in the center of the study area. The minimum convex polygon in hectares encompassing each animal's range was determined, as well as overlap among home ranges of individual lorises. Average home range sizes were: adult males, 3.6 ha +/- 0.09; subadult/smaller males, 1.17 ha +/- 0.26; and adult and subadult females, 1.59 ha +/- 0.24. Male ranges overlapped with at least 2-3 other adult males (0.72 ha +/- 0.23). Female ranges overlapped slightly with at least 2 other female ranges (0.22 ha +/- 0.25). Male ranges overlapped those of at least 3 females (0.82 ha +/- 0.51). Patterns of home range and sleeping site support previous suggestions of a multimale social system, similar to aye ayes and some galagos.     

Integration of a hand-reared chimpanzee (Pan troglodytes) infant into a social group of conspecifics

Rejections of infants among non-human primates occasionally occur in the wild as well as in captive settings. Controlled adoptions of orphans and introductions of individuals into new groups are therefore sometimes necessary in captivity. Consequently, behavioral research on integration procedures and on the acceptance of infants by adoptive mothers is much needed. In this study, the introduction and subsequent adoption were examined in an 18-month-old hand-reared chimpanzee (Pan troglodytes). The infant was introduced into an age/sex-diversified social group of conspecifics at Furuvik Zoo, Gävle, Sweden, and continuous focal data was collected during the final stage of integration, including infant care exhibited by the group members and the infant’s secure base behavior. The infant was successfully integrated into the group and engaged in positive social interactions with all group members. An adult primiparous female chimpanzee formed a bond resembling a mother–infant relationship with the infant, which continues to be maintained at publication. However, the female initially showed very limited interest in the infant. It was, in fact, two other younger female group members that exhibited most infant care. The infant’s secure base behavior patterns indicate that she adapted well to the new circumstances in the chimpanzee group as the integration progressed. This provides evidence that a final adopter does not necessarily initially show maternal interest and that there can be flexibility in maternal behavior in adult chimpanzee females. Moreover, the methods applied employing gradual familiarization with all the group members and the use of an integration enclosure, may have contributed to a successful result. These findings extend our knowledge of introduction procedures in captivity as well as provide information on foster mother–infant attachment in chimpanzees.     

Male-male competition and mating success in the orb-web spider,Nephila clavata,with reference to temporal factors

Seasonal occurrence patterns of adults of both sexes, intensity of male-male interactions, and mating success in the spider,Nephila clavata, were examined in the field. Adult males began to attend female webs about 2 weeks before female maturation. Large adult males were abundant in the early breeding season, but small males increased later in the season. From the distribution of males among female webs and size relationship of males within a web, male-male interactions seemed to be more intense when most females were still subadult. This was verified by a field experiment in which males were artificially introduced to female webs that were attended by other males. It was found that the probability of introduced males remaining on subadult female webs was lower than that on adult webs. As mating occurred mostly in the period shortly after the female final molt and first male sperm precedence was known in all spiders reported so far, intense male-male competition on subadult female webs seemed to be reasonable. Male longevity had an important influence on the mating success of males with just-molted females. Mating success was also affected by the relative body size of males present in a given period. Since larger males occupied the position closest to females within a web and stayed there longer, relative body size appeared to influence mating success through male-male competition. Female body size at maturation declined with time; hence, males that attained sexual maturity earlier had the advantage of mating with larger and more fecund females. Therefore, early maturation as well as larger size seem to be two important trairs influencing the reproductive success of males.     

Subadult male orangutan sociality and reproductive behavior at Tanjung Puting

During a four-year period at Tanjung Puting Reserve, Central Indonesian Borneo, subadult males were observed for 670.5 observation hours, 463 hours of which were as focal individuals. Subadult males were quite gregarious, participating in groupings for 40.9% of the time they were observed as targets. Subadult male sociality centered around females; 83% of the time subadult males spent in groupings was exclusively with females, as compared to 3% of contact time spent exclusively with other males. Much subadult male sociality can be understood in terms of male-male competition for females. Interactions between adult and subadult males were almost entirely determined by the presence or absence of females. Adult males were more belligerent when females were present. Twenty-two copulations or attempted copulations occurred during 16 subadult male-female encounters, two of which were consortships. The majority of subadult male copulations (86%) were resisted matings. Outside of consortship, resisted matings (or the first in a series of resisted matings or attempts) usually took place at encounter or shortly thereafter. Subadult males also surreptitiously followed adult males and their consorts. Subadults frequently located receptive females before adult males did but were replaced by adult males when these appeared. Subadult male reproductive strategy consisted of both sneak/“rape” and consort tactics with sneak/“rape” predominating.     

A case of adoption in a captive group of Mexican spider monkeys (Ateles geoffroyi)

A case of adoption of a 2.5-month-old infant by an adult female and its development in a captive group of spider monkeys is reported for a period of nine months. The female fully adopted the infant and in addition it was discovered that she was producing milk. The female had not been pregnant nor in contact with an adult male for 12 months prior to the adoption.     

Demographic and reproductive patterns in moustached tamarin monkeys (Saguinus mystax): Implications for reconstructing platyrrhine mating systems

In this paper we address a series of questions concerning reproductive opportunities, kinship, dispersal, and mating patterns in free-ranging moustached tamarin monkeys (Saguinus mystax). Between 1980 and 1990 information on group size, composition, and migration patterns was collected on marked groups of moustached tamarins inhabiting Padre Isla, an island in the Amazon Basin of northeastern Peru. In 1990, 86% of 114 animals residing in 16 social groups were trapped, examined, and released. Mean group size was 7.0, including 2.2 adult males and 2.0 adult females. None of these groups was characterized by a single adult male-female pair. In groups with more than one adult female, only the oldest female produced offspring. An examination of dispersal patterns indicates that transfers between groups were common and fell into several categories, including immigration of individual males and females, simultaneous transfer of pairs of subadult and/or adult males (sometimes relatives) into the same social groups, and group fissioning in which males and females of the splinter group join another small social group. We have no unambiguous cases of 2 adult/subadult females migrating together into the same social group. All 6 groups for which reproductive data were available were characterized by either a polyandrous or polygynous (polygyandrous) mating pattern. The results of this study indicate that moustached tamarins reside in small multimale multifemale groups that are likely to contain both related and unrelated adult group members. Kinship and social ties among males appear to be stronger and more longlasting than kinship and social ties among females. We contend that the modal mating system of moustached and many other tamarins is not monogamous, and offer the possibility that cooperative infant care and mating system flexibility in callitrichines evolved from a polygynous mating pattern. © 1993 Wiley-Liss, Inc.     

A case of adoption in a wild group of black-fronted titi monkeys (Callicebus nigrifrons)

We observed a case of infant adoption in an unprovisioned group of wild black-fronted titi monkeys (Callicebus nigrifrons). During our long-term field study we noticed that an infant had moved from one of our study groups (“Desbotado”) to another (“Rio”). Observations of the adoptive group confirm that it was being cared for by the adult male, and initially the group’s adult female was nursing the infant alongside her biological infant. Interestingly, the native and adoptive groups have frequent inter-group interactions, but at no point have we observed the native group trying to retrieve its infant. As of April 2007 the infant has been living in its adoptive group for 19 months. These data document the first case of adoption in this genus; they suggest that infant recognition is poorly developed in this species and that under certain circumstances wild groups of C. nigrifrons can successfully rear twins. In our study population reproductive females give birth to one infant every year; the only case when this has not happened is with the group that adopted the infant, suggesting that adoption may generate a reproductive cost.     

Co-existence of subadult males and females as alternative tactics of breeding post acquisition in a monogamous and protandrous anemonefish

Summary The monogamous and protandrous anemonefish,Amphiprion clarkii, utilizes only large host sea anemones as breeding sites. Under conditions of breeding site shortage, an important strategy for unmated fish may be to prepare themselves to enter quickly a breeding site from which a breeding male or female has recently disappeared. There are two types of subadults. Some juveniles become subadult males, which can change either to male or female afterwards, but others become subadult females, which can change only to female. Subadult females seem to acquire female posts more easily than subadult males. We develop an ESS model which evaluates the future reproductive success of subadult females and subadult males and test whether coexistence of subadult males and females can be interpreted as adaptive alternative tactics, using field data from two populations. The model predicts that if mortality does not differ between adult males and females the frequency for juveniles to become subadult females should be equal to the proportion of breeding post acquisition by subadult females among that by all subadults. The model also predicts that if mortality does not differ between subadult males and females, nor in adults, the frequency of subadult females among all subadults should be equal to the proportion of post acquisition. The model, with data from two study sites, suggests that alternative life-history pathways found inA. clarkii have evolved through adaptive tactics of breeding post acquisition.     

Microsatellite analysis of kinkajou social organization

Kinkajou social groups generally consist of one adult female, two males, one subadult and one juvenile. Based on analysis of variation in 11 microsatellite loci, we assess the degree of kinship within and between four social groups totaling 25 kinkajous. We use exclusion and likelihood analyses to assign parents for seven of the eight offspring sampled, five with >/= 95% certainty, and two with >/= 80% certainty. Five of six identified sires of group offspring came from the same social group as the mother and pup. Adult males and females within a group were unrelated and subadults and juveniles were offspring of the group adults, suggesting a family structure. All five identified paternities within a social group were by the dominant male of the group. However, this copulation asymmetry does not necessarily reflect cooperation due to kinship ties between the two adult males within a group as one of two adult male pairs sampled was unrelated. Neighbouring male kinkajous were more closely related to each other than neighbouring female kinkajous, suggesting that females disperse more often or farther than males.     

Enclosure utilization,activity budgets,and social behavior of captive chamois (Rupicapra rupicapra) during the rut

An observational study of chamois behavior during the rut was conducted at the Los Angeles Zoo. The herd consisted of an adult male, two adult females, two subadult females, and two kids (1.1). During the 13-week study, observers collected scan data on all animals and recorded all occurrences of selected social behaviors during interactions which involved the adult male. Scan observations showed that open areas of the enclosure close to the public were the least preferred, and areas with good rest places were used most. Overall the herd spent 73% of their time stationary, 13% foraging/feeding, 6% moving, and less than 5% each in object investigation, maintenance, play, and social behavior. The adult male rested and fed less, and stood vigilant and engaged in social behavior more frequently than the others. Nearest neighbor data showed clear patterns of kin association beyond the mother-last kid bond. The adult male interacted most often with the regular keepers, the subordinate female and the oldest subadult female. Interactions with the females consisted mostly of herding and sexual behaviors, while those with keepers were almost exclusively competitive/aggressive. While most findings paralleled those from studies of wild chamois, no study has previously reported long-lasting associations among kin.     

Social behavior of a group of orangutans (Pongo pygmaeus) on an artificial island in Singapore Zoological Gardens

The behavior of 12 orangutans (three adult males, two adult females, two subadult males, three adolescent males, and two infant males) was observed on a 450-m² island at the Singapore Zoological Gardens (SZG). Male orangutans (6–18 years old) showed less social and solitary play as they aged; adults (over 16 years old) were not seen to play. As they grew older males increasingly spent less time making physical contact, but the amount of time they spent in proximity (within arm's length) to others increased. Adult females regularly played with other group members. Contact, allogrooming, and social play showed nonrandom relationships between individuals. Adult females showed the most allogrooming and contact, adolescent and subadult males the most play. There was no obvious dominance hierarchy. One adult male spent about 10% of his time walking around the perimeter of the island. One-year-old infants rarely interacted with other individuals apart from their own and the other infant's mother. While orangutans lead relatively solitary lives in nature, it was concluded that the opportunities for social contact and play provided by the SZG orangutan island were beneficial to this species in captivity. Opportunities for social interaction provided the animals with a means of increasing the stimulus component of their environment, thus compensating for the inevitable restriction of complexity and unpredictability as compared with the wild state.     

Male-female affiliative relationships in naturally occurring ringtailed lemurs (Lemur catta) at the Beza-Mahafaly Reserve,Madagascar

Affiliative behavior between adult male and female ringtailed lemurs was examined as part of a project concerning male affiliation with conspecifics of all age/sex classes. Males in three social groups were studied over a 12 month period. Male-female preferred partnerships existed, and were variable according to reproductive season. Dominance rank, age, or tenure of the male did not appear to affect either the number of partnerships or frequency of affiliative behaviors that males had with females. However, males residing in groups with fewer males exhibited both higher frequencies of affiliative interactions with females and were nearest neighbors to females more often than males living in a group containing more males. Females were found to be responsible for proximity maintenance of male-female dyads in the majority of cases. Neither reproductive season nor seasonal availability of food resources strongly affected the frequency of affiliative interactions between males and females, it is proposed that an important aspect of successful group membership for male ringtailed lemurs relates to the development of social relationships with adult females. Males can benefit from such relationships in terms of greater centrality to the spatial core of the group, which can result in enhanced predator protection, greater opportunities for social contact, and potentially greater access to estrous females. © 1996 Wiley-Liss, Inc.