Post-conflict affiliation in common marmosets (Callithrix jacchus jacchus)

Post-conflict (PC) affiliation has been demonstrated in a number of Old World monkeys and apes, but very little is known about the occurrence of the phenomenon in New World monkeys. This study examined 282 PC interactions after spontaneous conflicts around feeding time in two family groups (N = 12) of captive common marmosets, Callithrix jacchus jacchus. We found an overall corrected conciliatory tendency of 31%. Selective attraction was seen: former opponents met significantly more often in PCs than in matched controls (MCs) (27% and 16%, respectively). There was no difference in the occurrence of PC affiliation between dyads consisting of parent-offspring constellations compared to offspring-offspring constellations. PC affiliative behaviors were seen in the first three minutes following conflict termination, and consisted mainly of proximity, play invitations, and food transfer. Notably, former opponents remained within arm's reach after 17% of conflicts. Affiliation was more likely to follow after conflicts involving play issues. The functional importance of the PC affiliation in marmosets remains to be examined.     

Hematology of common marmosets (Callithrix jacchus)

The hematology of the common marmoset (Callithrix jacchus) was investigated to provide reference values for the normal animal. Red blood cell counts, white blood cell counts, hemoglobins, mean cell volumes and differential white blood cell mean values were determined for Texas A&M colony-born animals and those obtained from the wild. The analyses were completed on 31 animals, three times each, for a total of 93 analyses, which included 16 colony-born and 15 wild-born marmosets. The hematological mean values found for marmosets were similar to those mean values reported for humans. The ranges for the hematology values were much narrower in the colony-born marmosets, and the average white blood cell count was significantly lower in these animals. This indicated that it is possible to produce and maintain a more uniform animal in the colony environment and, consequently, these animals are more suitable than wild-born animals for use as models for human research.     

Reproduction in captive common marmosets (Callithrix jacchus)

Though sexual maturation may begin at around one year of age, first successful reproduction of the common marmoset (Callithrix jacchus) is likely to be later, and it is generally recommended that animals not be mated before 1.5 years of age. The average gestation period is estimated to be 143 to 144 days. A crown-rump length measurement taken by use of ultrasonography during the linear, rapid, prenatal growth phase (between approx. days 60 and 95) can be compared against standard growth curves to estimate delivery date to within 3 to 4 days, on average. Marmosets produce more young per delivery than does any other anthropoid primate, and have more variation in litter size. Many long-established colonies report that triplets are the most common litter size, and there is documented association between higher maternal body weight and higher ovulation numbers. Higher litter sizes generally do not generate higher numbers of viable young. Marmosets are unusual among primates in having a postpartum ovulation that typically results in conception and successful delivery; reported median inter-birth intervals range from 154 to 162 days. However, pregnancy losses are quite common; one study of a large breeding colony indicated 50 percent loss between conception and term delivery. The average life span for breeding females is around six years; the range of reported average lifetime number of litters for a breeding pair is 3.45 to 4.0. Our purpose is to provide an overview of reproduction in the common marmoset, including basic reproductive life history, lactation and weaning, social housing requirements, and common problems encountered in the captive breeding of this species. A brief comparison between marmoset and tamarin reproduction also will be provided.     

Plasmodium knowlesi in the marmoset (Callithrix jacchus).

Common marmosets were shown to be susceptible to Plasmodium knowlesi malaria. The morphology of the parasite was indistinguishable from the observed in the natural host (Macaca fascicularis) and the common laboratory model (Macaca mulatta). A differential susceptibility to P. knowlesi was observed in the 8 marmosets studied. Multiplication rates of parasites were variable over 24 h periods. Five animals died of a fulminating infection within 12--17 days after challenge. Three animals recovered spontaneously from infection and were subsequently resistant to challenge with homologous and heterologous variants and strains of P. knowlesi. This resistance was maintained for intervals up to 100 days between challenge infections.     

Individual olfactory signatures in common marmosets (Callithrix jacchus)

Individual discrimination is likely a prerequisite for most primate social interactions. Olfactory cues are one set of stimuli used by primates to discriminate between individuals. Despite the importance of these olfactory signatures, there is little published research assessing the existence or function of individually unique odors among primates. This review systematically assesses behavioral and biochemical aspects of individual odors in a New World primate, the common marmoset (Callithrix jacchus). There are three objectives to this review: First, behavioral evidence for odors unique to the individual is evaluated in the context of results demonstrating that marmosets are able to discriminate between the scents from a familiar and a novel individual conspecific in behavioral bioassays under a variety of conditions. Second, biochemical evidence for individual scent signatures is debated with reference to studies examining qualitative and quantitative differences between the chemical compositions of scent-mark pools from adult females. A combined gas chromatography (GC) and mass spectrometry (MS) analysis demonstrated that each female had a unique ratio of highly volatile chemicals in the scent mark that could affect individual discrimination. Finally, the possible adaptive significance of individual odors in marmosets is debated. Individual odors may play a key role in regulating both female intrasexual competition and intersexual communication by providing a basis for the assessment of individual quality.     

Blood vitamin values of common marmosets (Callithrix jacchus)

The blood vitamin analyses of the common marmoset (Callithrix jacchus) were determined to provide baseline reference values for the normal animal. Ascorbic acid, riboflavin (erythrocyte glutathione reductase) [ECR], measurement, thiamin (erythrocyte transketolase) measurement and vitamin A (retinol) were determined for Texas A&M colony-born animals and those obtained from the wild. The analyses were completed on the animals, three times each, for a total of 93 analyses, which included 51 colony-born and 60 wild-born marmosets. A mean value of 0.98 mg/dl for ascorbic acid was found for the colony with a range from 0.06 to 4.1 mg/dl. The normal range for the marmosets appeared to be 0.5 to 1.5 mg/dl. The mean activity coefficient (AC) for the marmosets was 1.0 indicating that the animals had adequate riboflavin in the diet. The mean transketolase activities were (ribose remaining ?30.1 IU/L) and (sedoheptulose appearance ?7.9 IU/L). The mean and range for serum vitamin A (retinol) were 20.4 mg/dl and 6.96–57.44 mg/dl, respectively. None of the animals (colony-born or wild-born) exhibited any clinical signs of vitamin deficiencies as a result of being maintained in an indoor-outdoor environment over a three-year period.     

Angular momentum and arboreal stability in common marmosets (Callithrix jacchus)

Despite the importance that concepts of arboreal stability have in theories of primate locomotor evolution, we currently lack measures of balance performance during primate locomotion. We provide the first quantitative data on locomotor stability in an arboreal primate, the common marmoset (Callithrix jacchus), predicting that primates should maximize arboreal stability by minimizing side-to-side angular momentum about the support (i.e., L_sup). If net L_sup becomes excessive, the animal will be unable to arrest its angular movement and will fall. Using a novel, highly integrative experimental procedure we directly measured whole-body L_sup in two adult marmosets moving along narrow (2.5 cm diameter) and broad (5 cm diameter) poles. Marmosets showed a strong preference for asymmetrical gaits (e.g., gallops and bounds) over symmetrical gaits (e.g., walks and runs), with asymmetrical gaits representing >90% of all strides. Movement on the narrow support was associated with an increase in more “grounded” gaits (i.e., lacking an aerial phase) and a more even distribution of torque production between the fore- and hind limbs. These adjustments in gait dynamics significantly reduced net L_sup on the narrow support relative to the broad support. Despite their lack of a well-developed grasping apparatus, marmosets proved adept at producing muscular “grasping” torques about the support, particularly with the hind limbs. We contend that asymmetrical gaits permit small-bodied arboreal mammals, including primates, to expand “effective grasp” by gripping the substrate between left and right limbs of a girdle. This model of arboreal stability may hold important implications for understanding primate locomotor evolution. Am J Phys Anthropol 156:565–576, 2015. © 2014 Wiley Periodicals, Inc.     

Rapid diagnosis and management of parainfluenza I virus infection in common marmosets (Callithrix jacchus)

During 1983 a severe episode of respiratory infection occurred in a marmoset colony at these laboratories. Of 91 marmosets, 69 showed clinical signs of disease, one died and nine were so ill that euthanasia was necessary. Eight were examined post mortem and all showed consolidation of the lungs. Laboratory studies were carried out in an attempt to establish the cause of the outbreak and an interstitial pneumonia was found in seven animals which were examined histologically. Direct electron microscopy of nasal swabs and lung samples revealed the presence of a high titre of a paramyxovirus, and subsequent immunofluorescence studies established that the particular paramyxovirus involved was parainfluenza virus type I. Subsequent studies showed that surviving affected animals had seroconverted to parainfluenza I virus while animals that had not been implicated in the outbreak had not.     

Behavioral and cardiophysiological responses of common marmosets (Callithrix jacchus) to social and environmental changes

Under captive conditions common marmosets (Callithrix jacchus) show socially monogamous propensities. Male and female form a social bond as characterized by signs of behavioral arousal during separation of the pairmates, high levels of affiliative interactions between pairmates and agonistic responses towards strange conspecifics. In the present study behavioral and cardiophysiological responses of mated individuals of common marmosets were recorded while the animals were in an unfamiliar environment (1) alone, (2) with the pairmate, or (3) with an opposite-sexed stranger. Pairmates of 6 established pairs were tested in 3 replicates yielding a total of 36 trials per experiment. A trial was divided into three 10-min segments (baseline; unfamiliar environment; reunion). Behavioral responses were videotaped with a remote controlled camera system installed within the cage. Systolic (SBP) and diastolic blood pressure (DBP), and heart rate (HR) as well as locomotor activity (ACT) were recorded telemtrically through peritoneally implanted transmitters. The individuals’ responses measured while in an unfamiliar environment was only reduced by the pairmate, but not by an opposite-sexed stranger. No affiliative behaviors occurred between strange conspecifics, whereas aggressive and sexual behaviors were observed. During reunion with the pairmate individuals recovered physiologically. The present study shows that an individualized pair bond exists between pairmates of common marmosets. Further, it becomes evident that establishing a social bond with the pairmate is important for maintaining physiological homeostasis.     

Ingestion of calcium solutions by common marmosets (Callithrix jacchus)

Callithrix jacchus, the common marmoset, is a small New World primate that feeds on insects, fruit, and gum, and has a high reproductive rate for a primate. Insects are generally a poor source of dietary calcium, while gums may contain significant levels of calcium. Their high reproductive rate also suggests that reproductive female C. jacchus might be susceptible to calcium deficiency. Thus, we hypothesized that common marmosets might find solutions containing calcium to be palatable. We used choice experiments to examine this phenomenon in 14 male and 19 female common marmosets. Animals were presented with identical water bottles containing either deionized water or a calcium lactate solution (either 2% or 4% calcium lactate by weight) and intake was measured. Serum 25-OH-vitamin D was monitored in a subset of the animals in the experiment to examine the role of vitamin D in this behavior. Our results demonstrated that C. jacchus can distinguish between plain water and a calcium lactate solution, and that in general they prefer calcium solutions. Although animals with marginal vitamin D status did have strong preferences for calcium solutions, they did not ingest significantly more of the calcium solutions than animals that were vitamin D-replete. Nulliparous females and males did not differ in the amounts of calcium solutions ingested. Lactating females ingested the greatest volume of the calcium solutions.     

Poxvirus infection in a colony of common marmosets (Callithrix jacchus)

An epizootic poxvirus infection occurred in a colony of 80 common marmosets (Callithrix jacchus) recently introduced to a laboratory facility. Over an 18-week period, 29 of the monkeys exhibited skin lesions that persisted for 4-6 weeks. Although eight marmosets died during the outbreak, their deaths were not attributed directly to the poxvirus infection. The skin lesions developed over the entire body surface including the soles and palms. Initially characterized as erythematous papules, they quickly changed to elevated coalescing lesions with extensive scab formation. Histopathologically, the lesions revealed moderate to marked acanthosis, and they progressed to full-thickness epidermal necrosis and ulceration. Intracytoplasmic inclusion bodies were observed occasionally within degenerate keratinocytes. These inclusions most probably constituted the intracytoplasmic aggregates of viral particles observed ultrastructurally and confirmed as members of the poxvirus group by negative staining of direct skin scrapings.     

Differential infant carrying in captive and wild common marmosets (Callithrix jacchus)

Callitrichids are communal breeders that lack sexual dimorphism, and only a few studies have examined behavioral gender differences among them. The purpose of this study was to investigate gender differences in infant carrying in 16 captive and seven wild common marmoset groups. Our results showed that female–female twin pairs were carried significantly more often by fathers than were male–male and male–female pairs both in the wild and in captivity. We suggest these differences may be related to different reproductive potentials of male and female Callithrix jacchus and possibly to future breeding competition among females.     

Familial influences on ovulatory function in common marmosets (Callithrix jacchus)

Previous studies have indicated that many, but not all, female common marmosets (Callithrix jacchus) housed with their natal families undergo social suppression of ovulation. In this study, we further characterized ovulatory activity in common marmoset daughters to determine the prevalence of social suppression of ovulation and to elucidate familial influences on daughters' ovarian activity. Blood samples were collected twice weekly from each of 46 daughters for 5–12 months, usually beginning when the daughters were 12 months of age. Plasma progesterone concentrations indicated that 46.3% of daughters in intact natal families ovulated at least once, with the age at first ovulation averaging 17.2 months; however, none of these daughters became pregnant. Daughters' ovulatory cycles showed several significant differences from those of older females housed with unrelated adults, including longer periods between successive luteal phases, shorter luteal phases, and lower peak and mean luteal-phase progesterone levels. Daughters were significantly more likely to ovulate in families in which the mother was experimentally prevented from sustaining pregnancies, and in families in which the father had been replaced by an unrelated adult male and when the daughter was approximately 10–11 months of age. Daughters in families containing an older sister never ovulated; in contrast, those with a female littermate were not less likely to ovulate than were other daughters, but had more sporadic ovarian cycles and significantly lower mean luteal-phase progesterone levels. These results confirm and extend previous findings that up to half of female common marmosets may ovulate while housed with the natal family but that virtually none sustain pregnancies, suggesting that suppression of ovulation is only one of several components of reproductive failure. Furthermore, these results demonstrate that daughters' likelihood of ovulating, as well as the endocrine profiles of their ovulatory cycles, can be modulated by numerous social influences within the family. Am. J. Primatol. 41:159–177, 1997. © 1997 Wiley-Liss, Inc.     

Changes in hematological and serum biochemical parameters in common marmosets (Callithrix jacchus) after inoculation with dengue virus

Background Marmosets are susceptible to dengue virus (DENV) infection. However, blood parameter data and clinical signs of DENV-infected marmosets are limited. Methods Blood hematological and serum biochemical values were obtained from twelve DENV-inoculated and four mock-infected marmosets. Additionally, body temperature and activity level were determined. Results Five DENV-inoculated marmosets demonstrated thrombocytopenia, nine demonstrated leucopenia, and five demonstrated an increase in the levels of AST, ALT, LDH, and BUN. Additionally, seven DENV-inoculated marmosets demonstrated clinical signs including fever and decreases in activity. None of the four mock-inoculated marmosets demonstrated changes in either hematological or biochemical parameters. Conclusions Marmosets inoculated with DENV exhibited clinical signs and changes in hematological and biochemical parameters. The results suggest that blood parameter data and clinical signs could potentially be useful markers for understanding the progress of DENV infection in studies using marmosets.     

The development of infant-caregiver relationships in captive common marmosets (Callithrix jacchus)

The growing independence of infant common marmosets from their caregivers is promoted primarily by their caregivers, who increasingly often prevent the infants from climbing onto them and decreasingly often pick the infants up. Infants achieve independence from their mothers, fathers, and older siblings at different rates and develop characteristically different relationships with them. Infants that are most rejected by caregivers spend the least time on them. When rejected by their parents, infants tend to spend their time with their twins, rather than seeking to climb onto other caregivers. Caregivers do not compensate for unduly large or small amounts of care given by other members of the group. It is argued that if we are to understand the development of caregiver-infant relationships in species with multiple caregivers, we must discover the rules by which infants assess the amount of care they perceive themselves to have received and caregivers assess the amount of care they perceive themselves to have offered. The implications of a simple model based on expected levels of caregiving and careseeking are explored, particularly with respect to competition and compensation.     

The behavioral context of visual displays in common marmosets (Callithrix jacchus)

Communication is important in social species, and may occur with the use of visual, olfactory or auditory signals. However, visual communication may be hampered in species that are arboreal have elaborate facial coloring and live in small groups. The common marmoset fits these criteria and may have limited visual communication. Nonetheless, some (contradictive) propositions concerning visual displays in the common marmoset have been made, yet quantitative data are lacking. The aim of this study was to assign a behavioral context to different visual displays using pre–post‐event‐analyses. Focal observations were conducted on 16 captive adult and sub‐adult marmosets in three different family groups. Based on behavioral elements with an unambiguous meaning, four different behavioral contexts were distinguished: aggression, fear, affiliation, and play behavior. Visual displays concerned behavior that included facial expressions, body postures, and pilo‐erection of the fur. Visual displays related to aggression, fear, and play/affiliation were consistent with the literature. We propose that the visual display “pilo‐erection tip of tail” is related to fear. Individuals receiving these fear signals showed a higher rate of affiliative behavior. This study indicates that several visual displays may provide cues or signals of particular social contexts. Since the three displays of fear elicited an affiliative response, they may communicate a request of anxiety reduction or signal an external referent. Concluding, common marmosets, despite being arboreal and living in small groups, use several visual displays to communicate with conspecifics and their facial coloration may not hamper, but actually promote the visibility of visual displays. Am. J. Primatol. 75:1084–1095, 2013. © 2013 The Authors. American Journal of Primatology Published by Wiley Periodicals, Inc.     

Serum biochemical, hematological and body measurement data for common marmosets (Callithrix jacchus jacchus)

Blood samples were drawn and body measurements taken from healthy adult and juvenile common marmosets which had been housed under controlled environmental conditions for a minimum of 2 years. Blood was analyzed for serum biochemical and hematological constituents.