Relative taste preferences for food-associated sugars in the spider monkey (Ateles geoffroyi)

The purpose of the present study was to determine relative taste preferences for five food-associated sugars inAteles geoffroyi. Using two-solution choice tests of brief duration (5 min) four adult spider monkeys were given the choice between all binary combinations of sucrose, fructose, glucose, lactose, and maltose presented in equimolar concentrations of 20, 50, 100, and 200 mM respectively. Preferences for individual sugars were stable across the concentrations tested and indicate an order of relative effectiveness (sucrose>fructose>glucose≥lactose≥maltose) which is similar to results obtained with the same method in the squirrel monkey and to findings on relative sweetness in man. These results support the assumption that the order of relative effectiveness of the sugars under investigation found in the present study may represent a general pattern of preference in frugivorous and perhaps all primates.     

Gustatory Responsiveness to food-associated acids in the spider monkey (Ateles geoffroyi)

The gustatory responsiveness of four adult spider monkeys to five food-associated acids was assessed in two-bottle preference tests of brief duration (3 min). The animals were given the choice between a 30 mM sucrose solution and defined concentrations of citric acid, ascorbic acid, malic acid, acetic acid, or tannic acid dissolved in a 30 mM sucrose solution. With this procedure,Ateles geoffroyi was found to significantly discriminate concentrations as low as 5 mM ascorbic acid, citric acid, and acetic acid, 10 mM malic acid, and 0.1 mM tannic acid from the alternative stimulus. With the latter two substances, the monkeys rejected all suprathreshold concentrations tested, whereas with the former three substances, the animals showed an inverted U-shaped function of preference, i.e. they rejected high concentrations, but significantly preferred low but detectable concentrations of these acidic tastants over the alternative sweet stimulus. The results showed (1) the spider monkey to respond to the same range of acid concentrations as other nonhuman primate species; (2) thatAteles geoffroyi, is able to detect food-associated acids at concentrations well below those present in most fruits; and (3) that unlike most other primate species tested so far, spider monkeys do not generally reject acidic tastants but show a substanceand concentration-dependent change in responsiveness that may range from rejection to preference. The results support the assumptions that spider monkeys may use sourness and/or astringency of food-associated acids as a criterion for food selection, and that the gustatory responsiveness ofAteles geoffroyi to acidic tastants might reflect an evolutionary adaptation to frugivory.     

Comparative study of musculature in goldon monkey (Rhinopithecus)

Some differences between the muscular system of three species of golden monkeys were shown. The major features of the myology in these animals, besides that ofCercopithecoidea, are similar to the anthropoid apes and humans. Although most of the features between taxa of golden monkeys are largely homologous, there are also some differences. Our results differ slightly from thosePatterson (1942) obtained inR. roxellanae. Some conclusions reported by Patterson were obviously incorrect, since the specimen he used did not have a head. Many mylogical characters are similar to other species ofCercopithecoidea while some resemble those of apes. Many are similar to those of the leaf monkey, though some of them show much more development. The golden monkey is more advanced than any other species ofCercopithecoidea. We hypothesize that in terms of the myological characters the golden monkeys seem to occupy a position between the leaf monkeys and the apes.     

Gustatory thresholds for food-associated sugars in the spider monkey (Ateles geoffroyi)

The purpose of this study was to determine gustatory thresholds for five different food-associated sugars in Ateles geoffroyi. Using a two-bottle test, three adult spider monkeys were found to significantly prefer concentrations as low as 3 mM sucrose, 15 mM fructose, 20 mM glucose, and 10 mM lactose over tap water. Maltose was significantly discriminated down to 20 mM with individual animals showing either a preference or an aversion, or an inverted U-shaped function of preference toward higher concentrations of this carbohydrate. The results showed the spider monkey to respond to lower sugar concentrations compared to other nonhuman primates tested so far and thus support the assumptions that Ateles geoffroyi may use sweetness as a criterion for food selection, and that the remarkably high sweet-taste sensitivity of this frugivorous species might be correlated with its dietary specialization. © 1996 Wiley-Liss, Inc.     

Copulation in free-ranging black-handed spider monkeys (Ateles geoffroyi)

I report ad libitum data on 18 copulations involving free-ranging black-handed spider monkeys (Ateles geoffroyi) on Barro Colorado Island, Panama. All copulations were performed in a dorsoventral position, as is typically reported for this genus. Intromission often appeared difficult to achieve, possibly as a result of the large size of the glans penis in these animals. The average length from intromission to termination of thrusting exceeded 17 min, followed by an average period of almost 2 min before separation occurred, which suggests the possibility of a copulatory lock. Offspring of the female participant were almost always in close proximity to or in contact with the pair, and harassment by the offspring was observed only during the final stages of the copulation. All but one copulatory event occurred in complete seclusion from other adult males, and sexual behavior was not limited to any one adult male in the group.     

Social responses to the traumatic injury of a juvenile spider monkey (Ateles geoffroyi)

The behavioural development of a juvenile male spider monkey (Ateles geoffroyi) preceding and subsequent to a traumatic injury resulting in the loss of his tail, was documented over a nine-month period in Santa Rosa National Park, Costa Rica. The juvenile became heavily reliant on his mother, who readily provided compensatory care, including nursing the juvenile even though he had previously been weaned. In comparison to another juvenile male spider monkey of similar age, the development of the injured animal was severely retarded and even five months after the accident, the juvenile was still nursing and being carried by his mother. As injuries may be relatively common among primates it is suggested that the provision of compensatory care is an important trait in many primate species.     

Demography,ranging patterns,and activity budgets of black spider monkeys (Ateles paniscus chamek) in the Manu National Park,Peru

Results of a long-term field study on the ecology and social organization of two groups of black spider monkeys (Ateles paniscus chamek) in Peru are reported. Demography, ranging patterns, and activity budgets provide insight into some of the proximate determinants of fission-fusion social organization in this species and illustrate the different strategies used by males and females to gain access to critical resources. Longitudinal data on known individuals provide evidence for male natal philopatry and female emigration at sexual maturity in this population. Interbirth intervals are long (mean = 34.5 months) in comparison with most other primate species, and 5 of 15 infants seen within a few days of birth died or disappeared before they were a year old. Home ranges are large (150–250 ha) and fairly discrete; overlap with neighboring groups is on the order of 10–15%. Males and females differed substantially in their ranging patterns; females, particularly those with infants, restricted much of their ranging to a “core area” 20–33% the size of the total group range, whereas males ranged more evenly over the entire area occupied by the group. Daily path length varied over almost an order of magnitude from 465 m to 4,070 m, with a mean of 1977 m. Males spent more time traveling and less time feeding than most females. These results are compared with those obtained in previous studies of Ateles and with similar data from other primate species to assess their implications for the evolution of fission-fusion sociality in spider monkeys. The ecological factors responsible for the evolution of very similar social organizations in spider monkeys and chimpanzees are discussed.     

Forelimb anatomy of New World monkeys: myology and the interpretation of primitive anthropoid models

The forelimbs of 12 genera of New World monkeys, two genera of Old World monkeys, and a gibbon were dissected. Of the 54 muscles examined, 19 exhibited significant intergeneric variation. We present arguments for which morphologies are primitive and which are derived within platyrrhines and within anthropoids. We conclude that the forelimbs of Cebus apella and Callicebus moloch represent good models of the ancestral anthropoid morphology. Thus among living anthropoids they are most appropriate for comparisons with early fossil anthropoids. They are also useful for determining whether myological anomalies of human aneuploids are atavistic. Wagner tree analyses were conducted to assess the value of these myological characters in phylogenetic studies of platyrrhines. In most respects the Wagner trees were consonant with phylogenies previously proposed, although some hypothesized trees are less parsimonious than others in explaining our data. There is an unexpected number of derived features shared by Aotus and the Atelines. There are marked dissimilarities in forelimb musculature between Aotus and Callicebus.     

Effect of increasing trypsin concentrations on seminal coagulum dissolution and sperm parameters in spider monkeys (Ateles geoffroyi)

Seminal coagulum formation in spider monkeys (Ateles geoffroyi) interferes with the efficient recovery and evaluation of spermatozoa. The main objective was to assess the effect of increasing concentrations of trypsin on dissolution of seminal coagulum and spermatic parameters. Seminal coagulum was incubated at 37 °C without trypsin or in the presence of increasing trypsin concentrations (0.1%, 1.0%, and 5.0%). For each sample, coagulum dissolution time was measured, and sperm concentration, viability, motility, and morphology were evaluated using light microscopy and/or transmission electronic microscopy (TEM). Trypsin concentrations of 1.0% and 5.0% more rapidly liquefied seminal coagulum, averaging 32 and 21 min, respectively, compared with nontrypsinized controls, with maintenance of greater sperm viability (70.8% and 72.5%, respectively). Coagulum treated with 1.0% trypsin and the liquid ejaculate fraction averaged higher sperm motility (40.1% and 55.6%, respectively) than control samples, and both 1.0% and 5.0% trypsin treatment allowed recovery of increased numbers of motile spermatozoa. There was greater sperm fragmentation at the head and midpiece level after treatment with 1.0% and 5.0% trypsin (55.8% and 55.9%); however, the percentage of normal morphology in structurally intact spermatozoa did not differ relative to controls. With transmission electronic microscopy imaging, there were similar percentages of spermatozoa with plasma membrane swelling in the midpiece and acrosomal regions in trypsin-treated samples and controls. In conclusion, trypsin treatment of spider monkey seminal coagulum exerted a concentration-dependent effect on dissolution time and various spermatic parameters. Higher trypsin concentrations caused more rapid liquefaction of coagulum and recovery of greater numbers of motile spermatozoa, but may adversely affect fragmentation of spermatozoa and could compromise sperm function and cryopreservation potential.     

Dilated cardiomyopathy in a spider monkey (Ateles paniscus)

Background A spider monkey with severe dyspnea was referred to our clinic. Methods and Results Radiographs revealed an enlarged cardiac silhouette. Ventricular tachycardia and ST segment depression were also diagnosed after an ECG. These findings coupled with the postmortem examination confirmed dilatative cardiomyopathy. Conclusions This case is worthy of presentation since dilatative cardiomyopathy has been rarely encountered in spider monkeys.     

The menstrual cycle of the spider monkey (Ateles geoffroyi)

The ovarian cycles of four adult female spider monkeys (Ateles geoffroyi) were followed daily throughout 30 days by means of vaginal swabs and blood samplings. Cytological analyses of the vaginal swabs and radioimmunoassay determination of the daily levels of estradiol-17β (E₂) and progesterone (P₄) were done in order to classify the kind of ovarian cycle of this species. Our results show that Ateles geoffroyi females display menstrual cycles of about 24 days on average. By comparison with the well-known menstrual cycles of women, apes, and Old World monkeys, the four distinctive cytological phases (bleeding, follicular, periovulatory, and luteal) could be recognized; mid-cycle E₂ peaks followed by mid-luteal increases of the same hormone were present in all four females. P₄ levels were higher after the E₂ peak, although both hormones were present throughout the cycles. Also, age-dependent features, hormone profiles, and changes in menstrual phases lengths were detected. Am. J. Primatol. 44:183–195, 1998. © 1998 Wiley-Liss, Inc.     

Analysis of the shoulder in brachiating spider monkeys.

Adult spider monkeys (Ateles geoffroyi and A. paniscus) were conditioned to brachiate on a rope mill (an arboreal analogue of a treadmill). The postures and excursions of the shoulder girdle were studied by cineradiography. These data, together with conventional cinematographic and anatomical studies, permit reassessment of some characteristic structural and functional features of the shoulder in brachiators. During the propulsive phase, the shoulder joint moves caudad from fifth cervical to seventh cervical levels; at the same time, the joint moves dorsad (from a frontal plane midway between the first thoracic vertebra and the manubrium, to a frontal plane through the spinous processes) and slightly mediad. Spider monkeys position the scapula principally on the dorsum of the thorax, in contrast to quadrupedal primates which maintain a more lateral position (even in suspended postures). During brachiation, the scapula rotates a total of 35°; most of this rotation (20°) occurs in the non-propulsive phase when the free arm is being elevated to secure a new handhold. The sigmoidal shape, twisting of proximal relative to distal ends, and elongation of the clavicle in spider monkeys and other brachiators appear to be related to the specialized positioning of the shoulder girdle on the dorsum of the thorax. Shoulder and elbow movements contribute to the efficiency of the swing in terms of the dynamics of a pendulum.     

Aging-related reproductive decline in the male spider monkey (Ateles geoffroyi)

Background It is unknown whether male black‐handed spider monkeys (Ateles geoffroyi) undergo a reproductive decline as they age. The purpose of this work was investigating whether serum testosterone and semen quality decrease with age in these primates as occur in other species. Methods In this study, we assessed age variations in the concentration of serum testosterone, sperm counts, and motility in nine males. We took serum blood samples and semen samples by electroejaculation of anesthetized males throughout the fertile season. Results We found that testosterone levels and total sperm concentration, motile, progressive, fast linearly moving, medium linearly moving, slow linearly moving and immotile sperm significantly decreased with age. Conclusions Our results show that a reproductive decline occurs in male spider monkeys because of a decrease in sperm counts. These results are similar to those of rhesus monkeys and men, despite the phylogenetic distance between New and Old World primates.     

Influence of age,sex, and caging on joint mobility in the patas monkey (Erythrocebus patas)

Normal range of joint mobility in the extremities of the patas monkey, Erythrocebus patas, was established for a free-ranging colony of 64 animals at La Parguera, Puerto Rico (Caribbean Primate Research Center). Eighty-five animals that had been caged (30″ × 30″ cages) for up to 5 years were used for comparison. Passive joint mobility of anesthetized animals was measured with a goniometer. Nine parameters (five on the forelimb and four on the hindlimb) were measured on each animal. The data were sorted into subsets according to the animal's age, sex, place of birth, and type of confinement, if any. The number of animals in each subset was recorded and the mean (in degrees) and standard deviation for each parameter were calculated. A P?0.05 on two-tailed Student's t-tests was considered significant. Comparisons between free-ranging males and females showed significant differences in one or two parameters for all age groups. A cross-sectional sample of free-ranging animals of both sexes showed that significant changes in joint mobility occurred only in the first 18 months of life. Joint mobility of all caged animals, however, was highly variable, and even between the more mature animals there were significant differences in several parameters. Almost all comparisons of subsets of the same age and sex showed significant differences between caged and free-ranging animals in at least one parameter. When the caged animals were laboratory-born, however, these differences were significant in five out of nine parameters. The results suggest that, although caging itself affects joint mobility, the age of first confinement may have an even greater effect than the length of the confinement.     

Alloparental behavior in a captive group of spider monkeys (Ateles geoffroyi) at the Auckland zoo

I studied alloparental behavior in a captive group of spider monkeys at the Auckland Zoo using seven infants as focal subjects and assessed the effects of age, sex, and reproductive status of alloparents on patterns of infant-other interaction. Adult males initiated interactions with infants most often, followed by adult females. Immature individuals interacted with infants infrequently. Infants themselves initiated contact with adult males more often than with other members of the group. Alloparental behavior in spider monkeys differs from that in most other species in that the infant is an active rather than a passive participant in alloparental interactions. I discuss the patterns of infant-other interaction in relation to the social structure and dispersal patterns of Ateles.     

Radiation and speciation of spider monkeys,genus Ateles,from the cytogenetic viewpoint

The chromosomes of 22 animals of four subspecies of the genus Ateles (A. paniscus paniscus, A. p. chamek, A. belzebuth hybridus, and A. b. marginatus) were compared using G/C banding and NOR (nucleolar organizer region) staining methods. The cytogenetic data of Ateles in the literature were also used to clarify the phylogenetic relationships of the species and subspecies and to infer the routes of radiation and speciation of these taxa. Chromosomes 6 and 7 that showed more informative geographic variation and the apomorphic form 4/12, exclusively in A. p. paniscus, are the keys for understanding the evolution, radiation, and specification of the Ateles taxa. The ancestral populations of the genus originated in the southwestern Amazon Basin (the occurrence area of A. paniscus chamek) and spread in the Amazon Basin and westward, crossing the Andes and colonizing Central America and northwesternmost regions of South America. The evolutionary history of the northern South American taxa is interpreted using the model of biogeographical evolution postulated by Haffer [Science 185:131–137, 1969]. Ateles paniscus paniscus is the genetically most differentiated form and probably derives from A. belzebuth hybridus. Based on the karyotype differences, the populations of Ateles can be divided into four different group. These findings indicate the necessity of a more coherent taxonomic arrangement for the taxa of Ateles. Am. J. Primatol. 42:167–178, 1997. © 1997 Wiley-Liss, Inc.     

Seasonality of LH,testosterone and sperm parameters in spider monkey males (Ateles geoffroyi)

There are no reported data on hormonal fluctuations in black‐handed spider monkey males. On previous research about the reproductive physiology of this monkey we have found that during the dry season females show ovulatory estrogen peaks and males present the best quality semen. As part of an ongoing research, in this study we assessed seasonal variations in the concentration of serum luteinizing hormone (LH) and testosterone (T) in three adult spider monkey males to corroborate the seasonal reproductive synchrony. At the same time sperm count and motility were evaluated to search for any correlation between those sperm parameters and hormonal concentrations. We took blood and semen samples (by electroejaculation) of anesthetized males throughout the rainy (June–September) and dry (October–May) months. Our results revealed that T and LH were higher throughout the dry season and there was a significant correlation between T concentration and sperm count. Although higher during the dry season, sperm motility tended to correlate with testosterone and LH levels. These results demonstrated that black‐handed spider monkeys have a tendency to show a seasonal pattern of reproduction being the dry season the most likely time to achieve fertilization. Am. J. Primatol. 71:427–431, 2009. © 2009 Wiley‐Liss, Inc.     

Seasonal variation in association patterns of wild spider monkeys (<Emphasis Type="Italic">Ateles belzebuth belzebuth</Emphasis>) at La Macarena,Colombia

Spider monkeys exhibit a fission–fusion type of social organization. I studied party size and party composition in wild long-haired spider monkeys (Ateles belzebuth belzebuth) in three study periods at La Macarena, Colombia and found that overall party size was larger in the fruit-abundant season. Mean party size in which males were observed was relatively stable across seasons. In contrast, the mean party size of females varied. Females were observed in larger parties in the fruit-abundant season than in the fruit-scarce season. Moreover, whereas males associated with each other at an almost equal frequency across seasons, females associated with each other more frequently in the fruit-abundant season. Females with infants or small juveniles were more often in association with other individuals than were cycling females. The intensity of individual relationships varied according to season, such that even mothers and sons were not always strongly associated. In a large party, females with infants may gain from predation avoidance but they are at a disadvantage in terms of scramble competition. The balance between these factors may change with fruit availability and may influence party size in different periods. For males, party formation may facilitate the defense of resources from neighboring groups more than provide predation avoidance. Electronic Publication