A case study of primiparous maternal and infant gorilla (Gorilla gorilla gorilla) behavior

A primiparous mother and her infant were subjects of a longitudinal behavioral study at Lincoln Park Zoo in Chicago, Illinois. From November 1998 to November 1999, we collected a total of 100 hr of focal nonhuman animal instantaneous point sampling and all occurrence data on the mother and her infant. After 8 months, we introduced the 4-member focal group to an 8-member gorilla group, thus providing an opportunity to study the effect of the introduction on mother-infant behavior. Overall, time the pair spent physically apart was notably high with contact and proximate scores steadily decreasing over time. The infant was largely responsible for maintaining social proximity, rarely leaving the mother and frequently approaching her. In contrast, the mother left the infant frequently and approached the infant minimally. Maternal affiliative and nonaffiliative behaviors fluctuated throughout the study. Over time, both decreased. Despite a precarious maternal relationship, infant developmental trends were typical for captive gorillas. The results of this study suggest that allowing flexibility in judging maternal conduct can be of benefit to successful gorilla husbandry.     

Development of Independence from the Mother in Gorilla gorilla gorilla

In gorillas, the mother takes full responsibility for carrying and feeding offspring, and lactational amenorrhea prevents her from investing in another offspring while suckling. Therefore, mothers should encourage immature gorillas to become gradually more independent until they are physically able to acquire sufficient resources, travel independently, and manage social relationships unaided. We investigated the development of independence in a population of wild western gorillas (Gorilla gorilla gorilla) at Mbeli Bai, Nouabalé-Ndoki National Park, Republic of Congo. We observed the spatial proximity, the development of travel, patterns of suckling and weaning, and the nature of mother-offspring interactions for 42 immature gorillas to investigate the nature of the relationship between mother and offspring. Though mother-offspring distance and independent travel increased during immaturity, with few active interactions between the dyads, offspring still continued to suckle until a median age of 4.6 yr, longer than in mountain gorillas. The tolerance of the mother toward suckling by older offspring may reflect the importance of continued nutritional investment: the temporal nature of the diet of western gorillas means that succulent fruits—likely to be preferred weaning foods—are not always available. We propose that to buffer against potential fruit shortage, mothers continue to nurse their offspring to decrease the likelihood of death from care-dependent factors and to improve an offspring’s chances of survival.     

Mountain gorilla geophagy: A possible seasonal behavior for dealing with the effects of dietary changes

Geophageous Rwandan mountain gorillas excavate and eat weathered leucite-rich regolith (subsoil C horizons) from the slopes of Mount Visoke in the Virunga Mountains. In the months of the dry season, the gorillas reportedly ingest a halloysitic natural earth having a chemical composition similar to that of Kaopectate, a pharmaceutical used by humans to treat gastrointestinal upsets. Several plants known to contain potential toxins are consumed more heavily by gorillas in these months. New information from geochemical and mineral analyses suggests that geophagy may alleviate intestinal problems associated with changes in their diet because the ingested weathered regolith,containing halloysitic clay minerals, may act as a pharmaceutical agent that helps to adsorb toxins and to control dehydration in the dry season.     

Fertility in the male gorilla (Gorilla gorilla): Relationship to semen parameters and serum hormones

Circulating levels of steroid and protein hormones were measured in 17 adult male lowland gorillas (Gorilla gorilla). The population included both fertile and infertile males as identified by previous siring of offspring and presence or absence of spermatozoa in the ejaculate obtained by rectal probe electrostimulation. Correlations were sought between levels of testosterone, dihydrotestosterone, androstenedione, estrone, estradiol, progesterone, 170H-progesterone, dihydroepiandrosterone, luteinizing hormone, follicle-stimulating hormone (FSH), and potential fertility status. The results identify normal circulating levels of these hormones, and indicate that aspermatogenesis and infertility are not necessarily associated with any alteration in levels of gonadal steroids. There is an association of aspermatogenesis with elevation of FSH. Levels of adrenal androgens are more similar to other non-human primates than to the human, which is of interest because in other aspects of reproductive physiology so far investigated the gorilla has proved to resemble the human more closely than it does the other nonhuman primates.     

Aging: A shift from redox regulation to oxidative damage

Proteins, nucleic acids, and lipids can undergo various forms of oxidative modification. In numerous instances, these modifications result in irreversible loss of function. The age-dependent accumulation of oxidatively modified and dysfunctional macromolecules provides the basis for the free radical theory of aging. Pro-oxidants, however, are also capable of catalyzing fully reversible modifications to protein. It is increasingly apparent that these reactions participate in redox-dependent regulation of cell metabolism and response to stress. The adventitious use of free radical species adds complexity to the experimental and theoretical manner in which the free radical theory is to be tested and considered. Elucidation of mechanisms by which reversible oxidative processes are controlled, the components involved, and the metabolic consequences and how they are altered with age will provide new insight on the aging process and attempts to delay the inevitable.     

Pronucleus formation following in vitro fertilization of oocytes recovered from a gorilla (Gorilla gorilla gorilla) with unilateral endometrioid adenocarcinoma of the ovary

A 33-year-old, nonreproductive female gorilla was scheduled for ovariohysterectomy after diagnosing endometrioid adenocarcinoma of the right ovary; the contralateral ovary appeared small and inactive. Follicular recruitment and maturation were stimulated on the left ovary using human menopausal gonadotropin and human chorionic gonadotropin therapy. Three oocytes were recovered and inseminated using a thawed epididymal semen sample collected postmortem and cryopreserved. At 18 h postinsemination, one ovum was fertilized, the second showed evidence of polyspermia, and the third was unfertilized; no further embryonic development was observed. These results demonstrate that viable oocytes can be salvaged from a nonreproductive gorilla using a human exogenous gonadotropin treatment protocol and fertilized in vitro using cryopreserved/thawed epididymal gorilla semen.     

Asymmetric larval mobility and the evolutionary transition from siblicide to nonsiblicidal behavior in parasitoid wasps

The widespread evolution of gregarious development in parasitoidwasps presents a theoretical challenge because the conditionsunder which larval tolerance can spread in an intolerant populationare very stringent (the individual fitness of larvae developingtogether must increase with clutch size). Recent empirical workhas suggested that gregarious development can arise throughthe loss of larval mobility rather than through the gain oftolerant behavior. Using analytical genetic models, we exploredwhether decreased mobility presents a less stringent route togregariousness than the gain of tolerance. Reduced mobilitycan spread under a wide range of conditions. The critical conditionfor the spread of immobility is much less stringent than thatfor larval tolerance. In contrast with previous models of tolerance,the criterion for the spread of a rare immobility allele isindependent of any bias in the sex ratio and the likelihoodof single sex broods. Superparasitism increases the stringencyof the criterion for the spread of immobility, whereas doublekilling relaxes the criterion. Tolerance can subsequently replaceimmobility if there is any cost to the retention of fightingability. Our results suggest that asymmetric larval mobilitymay explain many instances of the evolution of gregarious development.     

Imprinted gene dosage is critical for the transition to independent life

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Highlights? Correct dosage of chromosome 12-imprinted genes is essential for postnatal survival ? Disruption of Dlk1 and Dio3 imprinting causes failure to adapt to independent life ? Maximal brown adipose activity is required as animals first leave the nest ? Dlk1 and Dio3 regulate maturation of brown adipose tissue     

A test of the cognitive social learning model of type A behavior

Portions of the cognitive social learning model proposed by Price as an explanation for the development and maintenance of Type A behavior were examined empirically. Specifically, the hypothesis that Type A behavior is fostered by various beliefs and fears and that these same beliefs and fears arise, in part, as the result of certain parental characteristics was investigated. A questionnaire assessing Type A behavior and the beliefs, fears, and parental characteristics proposed by Price was constructed and administered to a sample of males and females. The results indicated moderate associations between the variables examined for both males and females, with no significant gender differences in the pattern of relationships. The findings are congruent with relationships proposed by Price's model. Implications of the model are discussed in terms of additional research needed.     

Behavioral responses of an infant gorilla to maternal separation in a captive social group of lowland gorillas (Gorilla gorilla gorilla)

The present report describes behavioral reactions of a 33-month-old female infant gorilla to maternal separation in a captive social group whose composition is similar to that of wild groups. The infant gorilla responded differently to two types of maternal separation. When she remained alone for a few hours, she cried repeatedly and moved restlessly, indicating protest. Upon reunion and also for a few days thereafter, an intensification of the mother-infant relationship occurred. On the other hand, when she was separated from her mother but remained with the other group members for nine days, she did not display any behaviors that could be characterized as protest, but rather showed clear behavioral depression. During the 9-day separation period, she hardly played with other group members but she developed affiliative relationships with the leading male. After the reunion from the 9-day separation, she spent as much time near her mother as before separation and played with other infants at a level similar to that before separation, while she sometimes displayed behavioral patterns demanding the maintenance of physical contact with her mother. The present findings are compared with other reports in great apes and human children.     

Anterior dental microwear and its relationship to diet and feeding behavior in three african primates (Pan troglodytes troglodytes,Gorilla gorilla gorilla andPapio hamadryas)

Anterior dental microwear is shown to be related to diet and to feeding habits in three groups of extant African primates includingPan troglodytes troglodytes, Gorilla gorilla gorilla andPapio hamadryas. Five distinct types of incisal microwear are found in these groups. These include: fine wear striae, polish, small pits, large pits and microflakes. It is demonstrated that each species exhibits a different set of microwear types. Chimpanzees exhibit extensive pitting, mesiodistally oriented fine wear striae and small areas of polish, features of microwear that are probably related to the husking of hard fruit skins and the occasional stripping of leaves. Gorillas show large areas of polish, small pits and labiolingually oriented wear striae, a combination of features that may be associated with the stripping of leaves and pith. Baboons show extensive edge damage involving clusters of large pits and microflakes; this set of microwear types may be related to the initial chewing of gravel-laden seeds, roots and rhizomes. Microwear found on the canine/premolar complex of all three groups corresponds to the puncture-crushing and to the slicing of food.     

Observations on the ontogeny of feeding behavior in mountain gorillas (Gorilla gorilla beringei)

This report describes observations on the ontogeny of food choice in mountain gorillas (Gorilla gorilla beringei), made during a 17-month field study of mountain gorilla feeding ecology in the Parc National des Volcans, Rwanda. Data are presented on the feeding behavior of two infants observed from birth to the age of 8 months and on older infants and juveniles. This information is compared with data on the composition and diversity of the diets of young adults and adults in the same social group. Initial feeding by infants is usually synchronized with the mother's behavior: infants ingest the same food, or a different part of the same plant species, currently being eaten by the mother or just eaten by her. This suggests that observational learning is largely responsible for the transmission of food preferences. Most feeding by young infants, whether or not synchronized with the mother's, is on those foods eaten most frequently by adults. Infants also independently sample potential foods, some of which are apparently not consumed by adults. The frequency of sampling declines with age, although even adults occasionally ingest foods not observed to be eaten by other adults. By the age of 3 years, young mountain gorillas have developed the basic dietary patterns of adults, in terms of the number of foods eaten, the proportions in which specific foods are consumed, and diet diversity and equitability. There is a strong possibility that chemical cues influence food choice, but their role remains unclear.     

Protein flexibility from the dynamical transition: a force constant analysis

A standard analysis of the scattered neutron incoherent elastic intensity measured with very good energy resolution yields elastic scans, i.e., mean-square displacements of atomic motions (in a pico to nanosecond time scale) in a sample as a function of temperature. This provides a quick way for characterizing the dynamical behavior of biological macromolecules, such behavior being correlated with biological function and activity. Elastic scans of proteins exhibit a dynamical transition at approximately 200 K, marking a cross-over in molecular fluctuations between harmonic and nonharmonic dynamical regimes. This paper presents an approach allowing analysis of the elastic scan in terms of force constants and related parameters, such as the free energy barrier DeltaG at the transition. We find that the increased protein flexibility beyond the dynamical transition is associated with DeltaG approximately equals RT and effective force constants of the order of 0.1-3 N/m. The analysis provides a set of parameters for characterizing molecular resilience and exploring relations among dynamics, function, and activity in proteins.     

REM dreaming in the transition from late childhood to adolescence: A longitudinal study.

In this longitudinal developmental study, 12 boys and 12 girls provided REM dreams at 3 age levels: 9-11, 11-13, and 13-15 years. A total of 551 dreams were coded by 2 independent raters using C. Hall and R. Van de Castle's (1966) content categories. In addition, ratings of dream realism, the dreamer's self-involvement, and the frequency of speech acts were carried out. There was little change in the basic content categories of REM dreams. However, the frequency of unrealistic dream elements declined, whereas the ability to inventively put together separate contents of the memory system to produce meaningful scenes increased. Self-representation changed from passive experience to interactive involvement, along with an increasing number of speech acts by the dreamer. The similarity of the findings with Hall and Van de Castle categories to findings with home dreams from the same 24 participants is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Operant behavior in transition reflects neonatal exposure to cadmium

Male Long-Evans rats were injected with 0, 1, 3, or 6 mg/kg of cadmium chloride on the first day of life. Animals free of morphological stigmata at weaning were selected for study. Tissue concentrations of cadmium and operant behavior under various fixed-ratio (FR) schedules of reinforcement were evaluated when these rats were adults. Dose-related increases in cadmium were present in the brains, livers, and kidneys. Dose-related differences in behavior were most evident during the transition from fixed ratio 25 (FR 25 or 25 responses/reinforcer) to FR 75. An inverted U describes the relationship between response output during the transition to FR 75 and cadmium chloride dose response output increased at 3 mg/kg and decreased at 6 mg/kg. The rate decreases were not correlated with weight loss that appeared after some of the animals exposed to 6 mg/kg reached 60 days of age. Challenge doses of d-amphetamine revealed no interaction between neonatal exposure to cadmium and d-amphetamine. The occurrence of alterations in operant behavior in animals that appeared normal on a number of preweaning evaluations suggests that operant behavior in transition was sensitive to subtle effects not observed with other commonly used tests. The data provide evidence for delayed effects in the adult that are due to neonatal exposure to cadmium.     

Isolation and nucleotide sequence analysis of the beta-type globin pseudogene from human, gorilla and chimpanzee

The beta-globin gene cluster of human, gorilla and chimpanzee contain the same number and organization of beta-type globin genes: 5'-epsilon (embryonic)-G gamma and A gamma (fetal)-psi beta (inactive)-delta and beta (adult)-3'. We have isolated the psi beta-globin gene regions from the three species and determined their nucleotide sequences. These three pseudogenes each share the same substitutions in the initiator codon (ATG----GTA), a substitution in codon 15 which generates a termination signal TGG----TGA, nucleotide deletion in codon 20 and the resulting frame shift which yields many termination signals in exons 2 and 3. The basic structure of these psi beta-globin genes, however, remains consistent with that found for functional beta-globin genes: their coding regions are split by two introns, IVS 1 (which splits codon 30, 121 base-pairs in length) and IVS 2 (which splits codon 104, 840 to 844 base-pairs in length). These introns retain the normal splice junctions found in other eukaryotic split genes. The three hominoid psi beta-globin genes show a high degree of sequence correspondence, with the number of differences found among them being only about one-third of that predicted for DNA sites evolving at the neutral rate (i.e. for sites evolving in the absence of purifying selection). Thus, there appears to be a deceleration in the rate of evolution of the psi beta-globin locus in higher primates.     

Head-on collisions of waves in an excitable FitzHugh-Nagumo system: a transition from wave annihilation to classical wave behavior

For the particular case of an excitable FitzHugh-Nagumo system with diffusion, we investigate the transition from annihilation to crossing of the waves in the head-on collision. The analysis exploits the similarity between the local and the global phase portraits of the system. We find that the transition has features typical of the nucleation theory of first-order phase transitions, and may be understood through purely geometrical arguments. In the case of periodic boundary conditions, the transition is an infinite-dimensional analog of the creation and the vanishing of limit cycles via a homoclinic Andronov bifurcation. Both before and after the transition, the behavior of a single cell continues to be typical for excitable systems: a stable equilibrium state, and a threshold above which an excitation pulse can be induced. The generality and qualitative character of our argument shows that the phenomenon described can be observed in excitable systems well beyond the particular case presented here.