Philopatry and dispersion in the cotton-top tamarin,Saguinus (o.) oedipus: An attempted laboratory simulation

Cotton-top tamarins [Saguinus (o.) oedipus,Callitrichidae] living in cooperatively breeding, mature families in a captive colony were given the chance to explore a new living area. The aim was to simulate choices of philopatry versus dispersion. Breeding adults tended to stay home, as did eldest sons and still-dependent young offspring, but eldest daughters tended to go prospecting. The latter also spent more time in the new area and did more looking around while there. This confirms impression of female dispersion gained from records of “evictions” of daughters by other family members. These findings agree with those from field study and show noteworthy parallels with an avian cooperative breeder, the Florida scrub jay, Aphelocoma coerulescens.     

Parturition and perinatal behaviour in captive cotton-top tamarins (Saguinus oedipus)

Fourteen births to seven female cotton-top tamarins in a successful breeding colony were observed. All births occurred between 17:50 and 20:40. Behavioural changes indicating the onset of labour are described. Delivery was usually accomplished rapidly, with short intervals between successive infants. One suspected and one verified breech presentation occurred; these deliveries were accompanied by a marked increase in the duration of the interval between infants, and one infant apparently died during expulsion. All other presentations seen were vertex occiput posterior. Fathers, and sometimes older offspring of both sexes, frequently shared with the mother in eating the placenta. Carrying of infants by individuals other than the mother was rare in the hour after birth, and was usually confined to fathers. One primipara rejected her second-born infant, but all other parents showed competent parental behaviour from birth onwards. The results are compared to data from other primates, and their relevance to the successful breeding of this species is discussed.     

Changes in the activity of captive cotton-top tamarins (Saguinus oedipus) over the breeding cycle

The energetic costs of reproduction are likely to be particularly high in the Callitrichidae (marmosets and tamarins), which characteristically produce twin litters. The activity of five captive breeding pairs of cotton-top tamarins (Saguinus oedipus) was investigated for a 6-month period covering the second half of pregnancy and lactation. Breeding males showed few major changes in activity over this period, but breeding females reduced their levels of locomotion during late pregnancy, and during lactation they spent up to twice as much time feeding and foraging as they did during pregnancy. These results support the hypothesis that the costs that callitrichid females incur when reproducing are likely to have been an important factor in the evolution of these species' communal rearing systems.     

A field study of Geoffroy's tamarin (Saguinus geoffroyi) in Panama

A 3-month field study was conducted in Panama to determine presence and relative abundance of Saguinus geoffroyi, the Geoffroy's tamarin, and status of its habitat (see Acknowledgments for taxonomic note). This primate has a wide geographical distribution in eastern Panama; however, local distribution is highly variable. Tropical forest habitat is rapidly being converted for agriculture and timber. Areas where human access was strictly limited showed tamarin densities significantly greater than in less protected areas. Disturbance has a distinct impact on population densities. There may also be a relationship between tamarin abundance and specific types of vegetation. Future actions regarding the conservation of S. geoffroyi and its habitat are recommended.     

Regional (north american) studbook for the Geoffroy's tamarin,Saguinus geoffroyi

A regional (North American) studbook of Saguinus geoffroyi, Geoffroy's tamarin, is presented. Supplemental information regarding range, habitat, status in the wild, taxonomy, husbandry, level of inbreeding, and international holdings is included. Living animals are cross-indexed by holding institution.     

Birth seasonality in cotton-top tamarins (saguinus oedipus) despite constant food supply and body weight

Goldizen et al. (1988) reported that wild saddle-back tamarins (Saguinus fuscicollis, Callitrichidae) show birth seasonality that is correlated with food supply and body weight. They suggested a sequence of ultimate causality in which shortage of food leads to reduced body weight which leads to timing of weaning and lactation when resources are more abundant. Cotton-top tamarins in captivity show birth seasonality despite constant food supply and body weight. Although natural availability of fruit and insects (which are key foods for tamarins) is related to rainfall, birth seasonality and body weight in captive cotton-top tamarins are unrelated to rainfall. The most likely proximate mechanism for seasonality of births in tamarins is photo-period, given existing data on populations living in natural and artificial lighting.     

Contributions to infant care in captive cotton-top tamarins (Saguinus oedipus): The influence of age,sex, and reproductive status

Marmosets and tamarins are characterized by a reproductive strategy that includes twinning, and a communal rearing system in which infant care is shared among all group members, both breeders and nonbreeding helpers (often older offspring). In order to test some predictions about the extent to which different age-sex classes should invest in infants, contributions to infant carrying and food-sharing by all family members were measured in captive groups of cotton-top tamarins (Saquinus oedipus) ranging in size from 2 to 12 independent individuals. Fourteen litters were observed from birth to 12 weeks. Carrying by mothers decreased steadily over the study period, while carrying by fathers and other offspring increased for 3–5 weeks, then declined. Infants spent more time carried by siblings than by either parent, but parents did more carrying than individual siblings and, also, shared more food with infants. Older siblings contributed more care than younger siblings did. Adult sons carried infants more than adult daughters did, but immature daughters carried more than immature sons did. However, adult daughters actively offered food to infants more than any other class of helper did. These results were interpreted in the light of hypotheses concerning the reproductive and dispersal strategies of callitrichid species.     

A field study on the red-bellied tamarin,Saguinus l. labiatus,in Bolivia

A 5-month field study was conducted on red-bellied tamarins,Saguinus labiatus labiatus, in the Pando Department of northern Bolivia. Group sizes ranged from 5 to 10 animals, and each group associated with a group of saddle-backed tamarins,Saguinus fuscicollis weddelli. Members of three groups were trapped and marked and data were collected by radiolocation. The average range size used over 10 days was 19 ha. On average the groups entered about 29% of their range each day and had a mean daily path length of about 1487 m. The groups used a number of different sleeping sites within their ranges. They fed on a variety of different fruits and also on nectar from flowers, resin, and insects. Areas within the home range which were used significantly more than expected were generally those in which one or more of the following existed: a sleeping site, an intergroup encounter site, or a site where the group took shelter during an extended period of heavy rain.     

Composition and Proposed Nutritional Importance of Exudates Eaten by Saddleback (Saguinus fuscicollis) and Mustached (Saguinus mystax) Tamarins

I provide the first comprehensive data on the composition and mineral content of exudates eaten by saddleback (Saguinus fuscicollis) and mustached tamarins (S. mystax) and assess Garber's (1984; 1993) hypotheses on the potential nutritional importance of exudates in the diet of tamarins. In accordance with his initial findings, nutritional analyses show that the gums consumed are relatively high in calcium and may serve to balance a diet otherwise low in this mineral and high in phosphorus. However, the data on the seasonal variation in the amount consumed do not support the hypothesis that exudates are of particular nutritional importance during the later stages of gestation or lactation for saddleback or mustached tamarins.     

An experimental investigation of the pair bond in the callitrichid monkey,Saguinus labiatus

The strength and specificity of attraction between mated pairs of red-bellied tamarins (Saguinus labiatus) were tested in the laboratory. Test individuals were placed in a choice situation in which they could indicate their preference, by proximity and quality of behavior measures, to either their pair mate in an adjoining cage or an alternative in a second adjoining cage (same-sex animal, opposite-sex animal, or an empty cage). The test animals showed a significant preference to be in visual contact and proximity with their pair mates instead of the alternative when it was an animal of the same sex as the test individual or an empty cage. However, when the choice was between their pair mate and an animal of the opposite sex, no preference for their pair mate was apparent. No sex differences were found. It is concluded that attraction to a pair mate is not sufficient to maintain a pair bond, and when pairs ofS. labiatus breed monogamously, the pair relationship is likely to be maintained, at least in part, through aggression between same-sex individuals.     

Visual encounters between families of cotton-top tamarins,Saguinus oedipus

Territorial, cooperatively-breeding, incest-avoiding organisms have various options for securing mates and resources for breeding. Both philopatry and dispersal have many costs and benefits, but all are likely to include assessment of neighbours. Five families of cotton-top tamarins,Saguinus oedipus, in a laboratory colony were allowed to watch each other through a peephole. These encounters took place in a naturalistic, neutral zone outwith their home room or cage. Parents looked more at neighbours than did offspring. Older monkeys looked more than younger. Females looked more than males. The clearest effect was ofseniority: eldest offspring regardless of age were more eager lookers than were second-eldest than were third-eldest. The results make sense in terms of the monitoring of potential candidates for mate-recruitment or resource-acquisition, or for defense against outsiders with the same interests.     

Geophagy in moustached tamarins,Saguinus mystax (platyrrhini: Callitrichidae), at the Río Blanco,Peruvian Amazonia

During a field study at the Río Blanco in northeastern Peru between June and September 1990, moustached tamarins (Saguinus mystax) were observed to feed on soil material on three different occasions. Soil was taken directly from bare spots of surface soil (two observations) and from the broken mound of leaf-cutting ants (Atta sp.; one observation). Exposed surface soil is rare throughout the study area. Geochemical analyses of the soils that were consumed showed elevated concentrations of several elements in the ant mound sample compared to the other two soil samples. The most likely hypothesis for the function of soil feeding in moustached tamarins is that it serves in mineral supplementation.     

Geographical variations in the cranium ofSaguinus geoffroyi

In terms of craniometry, we examinedHershkovitz's hypotheses that, inSaguinus geoffroyi, populations on the western shore of the Rio Atrato were closely related toS. leucopus, and that a morphocline could be traced from the easternS. geoffroyi population to the western one. We detected a morphological sequence from east to west (or east to west) but did not find any evidence supporting the former hypothesis.     

Locomotor behavior and feeding ecology of the panamanian tamarin (Saguinus oedipus geoffroyi,callitrichidae, primates)

The Callitrichidae are a family of New World primates that exhibit a complex of behavioral and morphological characters reputedly similar to those of tree squirrels of the genus Sciurus.In particular, the locomotor behavior of tamarins and marmosets has been described as “squirrel-like. ” In this paper I describe a field investigation of the locomotor behavior and ecology of the Panamanian tamarin (Saguinus oedipus geoffroyi)and the redtailed squirrel (Sciurus granatensis).From January through August 1978, a total of 1200 hr was spent observing freeranging populations of tamarins and tree squirrels in an area of secondary forest on the Pacific Coast of Panama. Observations were made using an instantaneous time sampling technique. Individual activity records were collected on focal animals and recorded at 2.5-min intervals throughout the day. The following information was collected: (a) nature and structure of the substrate exploited, (b) activities on these supports and/or types of resources procured, and (c) body posture involved in the use of these supports. Data presented indicate major differences in substrate preference and positional behavior in tamarins and tree squirrels. Unlike squirrels, tamarins avoid vertical and sharply inclined supports during travel. Movements through the canopy is accomplished by a series of long leaps which begin and end on thin terminal supports. However, the Panamanian tamarin spent numerous hours clinging to large vertical trunks while feeding on plant exudate. Gums comprise 23.O% of the noninsect portion of the tamarin diet. The relationships between small body size, claw-like nails, substrate preference, and positional behavior are discussed. Claw-like nails enable this primate to exploit a food resource that would otherwise be inaccessible. The interrelationship between environment, behaviour, and morphology provides a frameworks from which to understand callitrichid adaptations. These adaptations are not convergent with those of the sciurid rodents. An earlier draft of this paper was presented at the 48th Annual Meeting of the American Association of Physical Anthropologists, San Francisco, April 1979.     

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.     

Reactions of wild tamarins,Saguinus mystax andSaguinus fuscicollis to avian predators

During a field study in northeastern Peru, the reactions of a group ofSaguinus mystax on Padre Isla and of a mixed-species troop ofS. mystax andSaguinus fuscicollis at the Río Blanco to raptorial and other birds were observed. Alarms that are specific to flying stimuli were elicited by birds of prey, but other birds that do not represent a threat to the tamarins also caused alarm calls. Alarm events (i.e., instances when one or more alarm calls were given) were observed at rates of 0.3/hr (Padre Isla) and 0.5/hr (Río Blanco). Rates of alarm events significantly increased after the birth of an infant in the Padre Isla group and after the attack of an ornate hawk-eagle (Spizaetus ornatus) on the Río Blanco group. Reactions to alarming stimuli/alarm calls ranged from looking up to falling down from trees. The modification of the tamarins' behavior by the potential presence of aerial predators indicates that raptors represent an important predatory threat to tamarins.     

Costs of Caregiving: Weight Loss in Captive Adult Male Cotton-Top Tamarins (Saguinus oedipus) Following the Birth of Infants

We examined changes in weight for 10 captive adult male cotton-top tamarins (Saguinus oedipus) from before the birth of infants through the first 16 weeks of infant life. Compared to before birth, males weighed significantly less in Weeks 1–4, 5–8, and 9–12 following the birth. Weights in Weeks 13–16 did not differ significantly from prebirth weights. Maximum weight loss for individual males ranged from 1.3 to 10.8% of prebirth body weight. Males in groups with fewer helpers lost significantly more weight than ones in groups with more helpers. For the 3 males that had no helper other than their mates, weight loss was particularly striking, ranging from 10.0 to 10.8% of their prebirth body weight. These results suggest that caring for infants is energetically costly, and that in this cooperatively breeding species, the presence of more individuals to share the burden of infant carrying reduces the cost to individual caregivers.     

Effects of Passage Through Tamarin Guts on the Germination Potential of Dispersed Seeds

Passage through tamarin guts may have an effect on seed germination potential. To examine these effects, and the variation between 2 sympatric tamarin species, we studied Saguinus mystax and S. fuscicollis in northeastern Peruvian Amazonia. For most of 39 plant species, neither germination success nor latency was modified by gut passage. Neutral effects on seed germination potential suggest that tamarins may fulfill criteria for effective seed dispersal.     

Bilateral giant myelolipoma in the adrenal of a cotton-top tamarin (Saguinus oedipus)

Abstract: A rare case of bilateral adrenal myelolipomas in a female cotton-top tamarin is reported. Large bilateral masses in the adrenal glands were composed of mature adipose cells containing varying amounts of hematopoietic cells of the myeloid, erythroid, and megakaryocyte series. The gross and histologic features of this case closely resemble human “giant” adrenal myelolipomas.     

Sociosexual development,pair bond formation,and mechanisms of fertility suppression in female cotton-top tamarins (Saguinus oedipus oedipus)

The effect of various social environments on sociosexual behavior was examined in six young female cotton-top tamarins (Saguinus oedipus oedipus) and in three established breeding females. Behavioral observations and hormonal samples were collected on young females while they were living with their families, when they were isolated from conspecifics, and after they were paired with an unrelated male. While living with the family, all females showed a suppression of fertility and low frequencies of sociosexual behavior. Following removal from the family, isolated females displayed an increase in rate of scent marking and an increase in hormonal levels. When young females were paired with males, they were exposed to scent secretions from their natal families, from an unfamilar family, and from a control for a total of 24 weeks. After pairing, hormonal levels increased dramatically, and ovarian cyclicity began. An increase in sociosexual behavior and elevated levels of scent marking accompanied this physiological change. Newly paired females had higher rates of affiliative behavior and scent marking than did established breeding females. However, both newly paired and established breeding males were more likely to initiate contact, grooming bouts, and social sniffing than were females. Time to first ovulation was later in females who were exposed to scent secretions from their natal families than it was in those females given a control for the first 8 weeks following pairing. No female conceived during exposure to scent secretions. However, once normal ovarian cycling had begun or a pregnancy was established, exposure to scent secretions had no effect. Thus, the social environment influences the fertility, sociosexual behavior, and pair bond formation of cotton-top tamarins. In addition, chemical stimuli found in the scent secretions produced by the natal family are most likely involved in reproductive suppression.