Blood serum proteins of squirrel monkey (Saimiri sciurea)

Blood serum proteins of 27 mature squirrel monkeys were studied by electrophoresis, immunoelectrophoresis, and starch gel electrophoresis. The normal protein content and its fractional composition (proteins, glyco- and lipoproteins) are presented. Comparative data showed that blood serum antigens of squirrel monkeys are less similar to those of man than are antigens of the Old World monkeys. Squirrel monkey did not show haptoglobin and transferrin polymorphism. Electrophoretical mobility of transferrin was very similar to that of human transferrin C, but the haptoglobin phenotype was similar to that of Cercopithecinae.     

Canonical discriminant analysis for hematological and serum biochemical changes during pregnancy period in squirrel monkeys (Saimiri sciurea)

Hematological and serum biochemical data obtained from non-pregnant, pregnant and post-partum squirrel monkeys (Saimiri sciurea) were analyzed by canonical discriminant analysis (discriminant analysis with reduction of dimensionality). All animals were of wild origin and had been maintained under uniform environmental conditions at Tsukuba Primate Center for Medical Science, N.I.H., Japan. Months were standardized by the day of parturition. The calculated arithmetic means and standard deviations were listed for each item of measurement performed. Items detected statistically significant difference (p less than 0.01) between months were as follows: red blood cell count (RBC), mean corpuscular volume (MCV), hematocrit value (Ht), hemoglobin concentration (Hb), white blood cell count (WBC), albumin concentration (ALB), blood urea nitrogen concentration (BUN), total cholesterol concentration (T-CHO), triglyceride concentration (TG), alkaline phosphatase activity (ALP) and calcium concentration (Ca). Results of canonical discriminant analysis showed that the value of the first canonical variate (Z1) decreased from the early period of pregnancy to the middle period, and that the second canonical variate (Z2) decreased from the middle period of pregnancy to the end of pregnancy. The meaning of their changes were discussed.     

Reproductive synchronization in squirrel monkeys (Saimiri)

Groups of squirrel monkeys (Saimiri) that are exposed to certain seasonal environmental stimuli experience a yearly reproductive cycle with discrete mating and birth seasons. Seasonal rainfall or some rainfall induced seasonal changes (such as changes in vegetation or insect fauna) appear to be responsible for timing theSaimiri reproductive cycle. Animals of both sexes show significant physiological and behavioral changes during the yearly cycle. Whether the environmental timing factors affect both the males and the females equally, or affect only one sex directly and the other sex indirectly through social communication is not clear. Three mechanisms by which the reproductive activity of both males and females could be synchronized are presented, and data from a laboratory study and a field study relevant to each mechanism are presented. Several social interaction patterns frequently observed in the field study suggest that (1) male sexual activity may excite female sexual activity through male penile display and/or other stereotyped interactions and/or (2) female sexual activity may excite male sexual activity through pheromone and/or other communication channels.     

Distribution of lipofuscin in the squirrel monkey Saimiri sciurea

Synopsis The body-wide distribution of a pigment present in many organs of squirrel monkeys (Saimiri sciurea) is described. The pigment, which was identified by histochemical techniques as lipofuscin, occurred intracellularly in some organs, and extracellularly in others.     

Play vocalizations of squirrel monkeys (Saimiri sciureus)

Vocalizations occurring during play bouts were studied in 2 pairs of young male squirrel monkeys. Two main call types, one having four variants, are described. Vocalization rate varied with the type of ongoing behavior and with play bout duration, an association considered to be indicative of motivation to play. Structural differences also varied with bout duration and longer bouts had longer and more complex calls. In addition to providing direct information about motivation, vocalizations may have a metacommunicative function in alerting adult group members (not play partners) to the presence of playful activity.     

Chemotherapy of haemobartonellosis in squirrel monkeys (Saimiri sciureus)

Splenectomised Saimiri sciureus squirrel monkeys are being used increasingly as an experimental host for human malarial studies, notably for the assessment of candidate vaccines against Plasmodium falciparum blood-stage infection. Recently, we have reported that colony-reared S. sciureus monkeys are asymptomatic carriers of Haemobartonella sp. and that patent Haemobartonella infection, activated following splenectomy, may interfere with the course of P. falciparum parasitaemia in these animals. For several years, splenectomised S. sciureus monkeys were routinely submitted to oxytetracycline therapy before their use in malarial studies in order to prevent a possible spontaneous Heamobartonella infection. However, we report here that such antibiotic therapy is often ineffective and that neoarsphenamine chemotherapy may be considered as an alternative to cure both latent and patent haemobartonellosis in S. sciureus monkeys.     

Food-storing behavior in captive squirrel monkeys (Saimiri sciureus)

Observations of food-storing in caged squirrel monkeys are described. Frequencies of storage and attempted retrievals increased with the introduction of novel objects. The type of storage site, its location and defense, all indicate hiding of food or favored objects to avoid stealing attempts rather than food or object play behavior.     

Reconciliation in captive Guyanese squirrel monkeys (Saimiri sciureus)

The tendency for agonistic interaction to increase the probability of friendly interaction between social partners has been demonstrated across a range of Old World primates. While research on such post-conflict behavior proceeds into an hypothesis-testing phase, new comparative information must accumulate to provide full phylogenetic perspective on primate social behavior. Data from New World and prosimian primates are yet extremely limited. We studied captive squirrel monkeys (Saimiri sciureus) via post-conflict (PC) and matched control (MC) observations and analyzed results using both the PC-MC and time-rule methods. Former opponents maintaining affiliative relationships soon engaged in friendly interaction following large proportions of agonistic interactions, whereas non-affiliated individuals, including virtually all male-female pairs, reconciled conflicts rarely. Close-proximity approaching and huddling contact constituted the principal modes of post-conflict amicability. Agonistic interactions of relatively high intensity were most likely to be reconciled and most likely to be reconciled via physical contact. High vulnerability of Saimiri to predation may have favored this species' strong inclination to reconcile soon after agonistic interaction. Research on free-living populations of this and other primate species is needed to illuminate similarities and differences across taxa.     

Microsatellite polymorphisms in Bolivian squirrel monkeys (Saimiri boliviensis)

Two different approaches were used to identify new microsatellite polymorphisms among captive Bolivian squirrel monkeys (Saimiri boliviensis). In the first case, PCR primers for published human microsatellite loci were screened using genomic DNA from squirrel monkeys. Six polymorphic loci were identified using DNA samples from 19 unrelated individuals. The average heterozygosity among these six loci is 0.73. In the second set of experiments, a DNA library was created from Saimiri genomic DNA, and clones were selected from that library by screening with probes containing di-, tri-, and tetranucleotide repeats. Six novel microsatellites were identified this way, with an average heterozygosity of 0.59. Primer pairs for these six cloned microsatellites were also screened using a series of DNA samples from ten other platyrrhine species to assess the potential utility of these loci in other taxa. This study provides 12 new DNA polymorphisms that will be useful for various studies of this genus and demonstrates that both approaches can be used to develop new DNA polymorphisms in platyrrhine species.     

Abnormal behaviors in nursery-reared squirrel monkeys (Saimiri sciureus)

Seventeen squirrel monkeys (Saimiri sciureus), 11 nursery-reared and six mother-reared, were monitored to clarify the type and degree of deviant behaviors that result from rearing this species in the nursery. Two observation periods were used: the first when the subjects averaged 6.7 months of age, the second when they averaged 15.5 months. Thirteen activities involving variations of nonnutritive orality, stereotypic posturing, and agitated behaviors were seen in the nursery-reared subjects, but never in the mother-reared subjects. No consistent gender, subspecies, or age differences were evident. Squirrel monkeys, like chimpanzees and some Old World monkeys, do develop atypical self-directed behaviors when deprived of normal stimulation during early development.     

Seasonality of reproduction in captive squirrel monkeys (Saimiri Sciureus)

Seasonality of reproduction is believed to be influenced by environmental factors such as humidity, temperature, and photoperiod. In primates, there has been much speculation about which environmental factors have the greatest influence on reproductive seasonality. To determine whether environmental factors affect seasonality of reproduction of squirrel monkeys in captivity, I used path analysis to compare number of births and matings per month with monkeys kept in indoor enclosures (maintained at optimal temperatures) and those kept in outdoor enclosures (exposed to the elements). Since a different pattern of seasonality was found to occur, I was able to test whether temperature, rainfall, or photoperiod could explain the temporal variation in reproduction. Squirrel monkeys raised in captivity displayed different patterns of seasonality of reproduction, depending on the conditions in which they are housed ( chi(2)3 25.12, P<0.001; G = 28.10, P<0.001). Temperature seemed to have a large impact on number of births and matings per month (matings: path coefficient = 0.799; births: path coefficient = -1.315). Understanding what factors regulate reproduction for animals and how these factors affect reproduction differently in wild versus captive populations are important to conservation and management of species.     

Characterization of Gilbert-like syndrome in squirrel monkeys (Saimiri sciureus)

Bolivian squirrel monkeys, unlike those of Brazilian origin, exhibit a marked fasting hyperbilirubinemia (FH) similar to that observed in Gilbert's syndrome in man. Since no delays in the hepatic clearance of sulfobromophthalein or indocyanine green are present, the Bolivian monkey appears to be similar to Gilbert's type I syndrome. FH can be significantly decreased by either phenobarbital or tin-protoporphyrin pretreatment. Nicotinic acid-induced hyperbilirubinemia and delayed tolbutamide clearance were not observed as in the human syndrome.     

Mycobacterium kansasii infection in squirrel monkeys (Saimiri sciureus sciureus)

Abstract: This report documents asymptomatic infections of Mycobacterium kansasii in four of five tuberculin positive squirrel monkeys (Saimiri sciureus sciureus). The mycobacterial DNA amplified by polymerase chain reaction (PCR) from a bronchial lymph node had no affinity for the species specific probes of M. tuberculosis, M. avium, and M. intracellular, thus allowing the presumptive diagnosis of an atypical mycobacterial infection. Infection by Mycobacterium kansasii was confirmed by culture of bronchial lymph nodes from three monkeys. The source of the infection was never identified.