Ana María Santillán-Doherty

Astronomical and meteorological parameters and rest-activity rhythm in the Spider monkey Ateles geoffroyi

UNLABELLED All animals including primates show regular variations in their behavioural activities and physiological functions. In numerous species diel, ultradian, infradian, annual and/or lunar rhythms have been established; however, the use of the focal sampling method does not provide information on hour-to-hour nor day-to-day variations. In behavioural field studies dealing with primate activity rhythms and their modulation by environmental variables the possible dual, synchronizing and/or masking effect of these variables is often ignored. In the present study, we analyze the relation between astronomical and meteorological parameters and various parameters of the rest-activity rhythm in Ateles geoffroyi, a species scarcely investigated with respect to biological rhythms. These Ateles were kept under semi-natural conditions, exposed to natural light, temperature and humidity cycles, and sky state. Motor activity was recorded with actiwatch accelerometers during 180 days (5-min intervals), starting from the autumn equinox. RESULTS Ateles is active throughout the day, rests during the night and presents bimodal activity. Activity time, onset and end of activity as well as the times of their two activity peaks were significantly correlated with duration of the solar day and sunrise or sunset time. The behavioural parameters also correlated with ambient temperature. Climate factors and sky-state significantly influenced the duration and times of onset and end of activity. Our findings identified a clear modulation of the rest-activity pattern by astronomical variables serving as Zeitgebers, such as the natural light-dark cycle, and by masking effects of meteorological factors (temperature, weather and cloudiness), as well as of artificial variables introduced by the interaction with man.

Novelty-Seeking Temperament in Captive Stumptail Macaques (Macaca arctoides) and Spider Monkeys (Ateles geoffroyi)

Novelty-seeking temperament is defined as the reaction to novel or risk situations and objects, and by the global disposition to explore such stimuli. Our purpose was to describe and compare this trait in primates. For this purpose, a risk-taking Index, a curiosity index, and a novelty-seeking index were correlated to several biosocial variables using 22 captive stumptail macaques (Macaca arctoides) and 7 captive spider monkeys (Ateles geoffroyi). Spider monkeys scored higher than macaques, males of both species scored higher than females, and dominant macaques were evaluated as more novelty seekers. We suggest that these differences may be because of, among other reasons, the particular social system of each species.

Recording vocalizations with Bluetooth technology.

We propose a method for capturing vocalizations that is designed to avoid some of the limiting factors found in traditional bioacoustical methods, such as the impossibility of obtaining continuous long-term registers or analyzing amplitude due to the continuous change of distance between the subject and the position of the recording system. Using Bluetooth technology, vocalizations are captured and transmitted wirelessly into a receiving system without affecting the quality of the signal. The recordings of the proposed system were compared to those obtained as a reference, which were based on the coding of the signal with the so-called pulse-code modulation technique in WAV audio format without any compressing process. The evaluation showed p < .05 for the measured quantitative and qualitative parameters. We also describe how the transmitting system is encapsulated and fixed on the animal and a way to video record a spider monkey’s behavior simultaneously with the audio recordings.

Season of Birth in Schizophrenia in the Mexico City Area: Comparison with General Population

The relationship between seasonal changes and mental disorders has been extensively studied in the northern and southern hemispheres. In both cases, the results show that there is a higher rate of schizophrenic births during the winter months. The present study attempts to prove the existence of this phenomena in Mexico City, an area that does not undergo extreme weather variations throughout the year. A total of 2,288 schizophrenic patients was considered for this study. Their date of birth was compared to that of the general population of the Mexico City area, a total of 4,848,119 individuals. The number of births was evaluated according to the number of days in each month. The distribution of the births of schizophrenics was compared to the reference population by means of a Kolmogorov-Smirnov test and a X 2 contrast. The annual rhythm of births of schizophrenics was determined through an analysis of the Estimated Seasonal Component. There was a slight, non-significant increment in schizophrenic births in December and autumn, as compared with the general population birth rate. Interestingly, it was found that births in the control population decreased significantly in December when compared with all the other months. Results were discussed in relation to the geographical location of Mexico, which lies in a tropical zone, and as a consequence minimal seasonal effects.

Sleep in the spider monkey (Ateles geoffroyi): A semi-restrictive, non-invasive, polysomnographic study

The normal sleep patterns of the spider monkey (Ateles geoffroyi) have not been described yet. The objective of this study was to characterize the electrophysiological patterns, sleeping postures, and sleep‐wake cycle in semi‐restricted spider monkeys. Continuous 24‐hr polysomnographic (PSG) recordings, involving simultaneous recording of non‐invasive electroencephalographic (EEG), electro‐oculographic (EOG), and electromyographic (EMG) activities, were carried out in captive monkeys living in outdoor rainforest enclosures. Electrode placement was done according to the human international 10–20 system. Specific behaviors displayed by monkeys during the sleep‐wake cycles were correlated with the PSG recordings. The nycthemeral distribution of the sleep‐wake cycle was also calculated. The results show that electrophysiological N‐REM sleep patterns in spider monkeys are similar to those observed in other primates, including human beings. Furthermore, a vertical semi‐fetal posture was observed during N‐REM and REM sleep phases. The amount of nocturnal sleep was significantly higher than that of the diurnal period, showing that the spider monkey is a diurnal primate. An outstanding finding was the absence of muscular atonia during the spider monkeys REM sleep, which suggests that arboreal primates have developed a neuromuscular mechanism specialized for sleeping in a vertical posture. Am. J. Primatol. 77:200–210, 2015.

Lunar and Seasonal Rhythms and Childhood Mortality

The aim of the present study was to assess the effect of the lunar cycle phases, the lunar apogee and perigee, and the geophysical factors (humidity, temperature, and rainfall) on the childhood mortality. We designed a retrospective study by reviewing the clinical charts of the population of patient deceases during the lunar pre-phase (a day before), phase (day of lunar change of phase), and post-phase (a day after), between the years 1991–1996 in a children’s hospital. From the 44,982 discharges from the hospital in the interval between 1991 and 1996, 2003 corresponded to mortal cases, and 522 died within the 3 days we considered as representative for each phase. The number of deaths was approximately the same in between phases. The percentage of male deaths was higher during phase days than interphase ones. Male deceases exhibited a statistically significant predominance during lunar first quarter, full moon, and new moon. A discreet increase of mortality was present in the months of March, June, August, September, October, and November, as well as during summer and fall, but these increments were not significant. Minimum and maximum temperatures exhibited no relation to this behavioral pattern for deceases, nor the humidity index. Early lactating infants presented a significant higher mortality during November, December, and March. We suggest to investigate the causes of the increase of deceases in males in relation to the circalunar rhythms, as well as the lift up of deceases in neonates and early lactating children during November and December.

Acoustic variation of spider monkeys’ contact calls (whinnies) is related to distance between vocalizing individuals and immediate caller behavior

Due to several factors such as ecological conditions, group size, and social organization, primates frequently spend time out of visual contact with individuals of their own group. Through the use of long‐distance vocalizations, often termed “contact calls,” primates are able to maintain contact with out‐of‐sight individuals. Contact calls have been shown to be individually distinct, and reverberation and attenuation provide information about caller distance. It is less clear, however, whether callers actively change the structure of contact calls depending on the distance to the presumed listeners. We studied this question in spider monkeys (Ateles geoffroyi), a species with complex spatial dynamics (fission‐fusion society) that produces highly frequency modulated contact calls, denominated “whinnies.” We determined the acoustic characteristics of 566 whinnies recorded from 35 free‐ranging spider monkeys that belong to a community located in Mexico, and used cluster analyses, discriminant function analyses, and generalized linear mixed models to assess if they varied in relation to the presumed distance to the listener. Whinnies could be grouped into five subtypes. Since the lowest frequency subtype was mainly produced by spider monkeys that exchanged whinnies at longer distances, and lower frequency calls propagate across longer distances, our results suggest that whinnies vary in order to enhance vocal contact between individuals separated by different distances. Our results also revealed that whinnies convey potential information about caller immediate behaviors and corroborated that these calls are individually distinct. Overall, our results suggest that whinny acoustic variation facilitates the maintenance of vocal contact between individuals living in a society with complex spatial dynamics.

Efecto del enriquecimiento ambiental en un grupo de monos araña (Ateles geoffroyi) en cautiverio

SUMMARY Captive animals suffer from stress and lack of stimulation. Environmental enrichment (EE) provides them with a series of activities that encourages them to present species-specific behaviors. The objective of this work was to analyze the effect of an EE program in the behavior of a 7-spider monkey colony. It was expected that aggression, coprophilia and stereotypes would be less frequent, while exploration and play would increase. The study was divided in two stages: one previous to EE and one while EE was being implemented. A focal sampling per behavior was undertaken in 1-h continuous recordings for a total of 40 hours per stage. We compared the frequency of each behavior with a Wilcoxon’s signal test. The results showed that aggression, stereotypes and coprophilia were reduced during EE, while exploration and play increased significantly. No significant differences were found between sexes. EE reduces the problems originated by confinement; therefore, it must be considered a necessary tool to be continuously employed to make an improvement into the life conditions of confined individuals.