Scholars@Duke
Christine M. Drea

Christine M. Drea

Professor in the Department of Evolutionary Anthropology
Evolutionary Anthropology
cdrea@duke.edu
Duke Box 90383, 08 Bio Sci Bldg, Durham, NC 27708-0383
129 Bio Sci Bldg, Durham, NC

Selected Publications

Maternal Androgens in Dominant Meerkats (<i>Suricata suricatta</i>) Reduce Juvenile Offspring Health and Survivorship.

Journal Article Ecology and evolution · November 2024 In oviparous vertebrates, maternal androgens can alter offspring immune function, particularly early in development, but the potential for negative health effects of maternal androgens in mammals remains unclear. We investigated the relation between matern ... Full text Cite

Integrating microbiome science and evolutionary medicine into animal health and conservation.

Journal Article Biological reviews of the Cambridge Philosophical Society · April 2024 Microbiome science has provided groundbreaking insights into human and animal health. Similarly, evolutionary medicine - the incorporation of eco-evolutionary concepts into primarily human medical theory and practice - is increasingly recognised for its no ... Full text Cite

Does oxytocin modulate cortisol in ring-tailed lemurs? A test of the social buffering effect

Conference AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY · 2024 Cite

Androgen-mediated maternal effects and trade-offs: postnatal hormone development, growth, and survivorship in wild meerkats.

Journal Article Frontiers in endocrinology · January 2024 IntroductionMammalian reproductive and somatic development is regulated by steroid hormones, growth hormone (GH), and insulin-like growth factor-1 (IGF-1). Based largely on information from humans, model organisms, and domesticated animals, testos ... Full text Open Access Cite

Effects of oxytocin receptor blockade on dyadic social behavior in monogamous and non-monogamous Eulemur.

Journal Article Psychoneuroendocrinology · April 2023 A prominent body of research spanning disciplines has been focused on the potential underlying role for oxytocin in the social signatures of monogamous mating bonds. Behavioral differences between monogamous and non-monogamous vole species, putatively medi ... Full text Cite

MEASURES OF LEMUR PHYSIOLOGICAL AGING

Conference AMERICAN JOURNAL OF PRIMATOLOGY · 2023 Cite

Microbial rewilding in the gut microbiomes of captive ring-tailed lemurs (Lemur catta) in Madagascar.

Journal Article Scientific reports · December 2022 Microbial rewilding, whereby exposure to naturalistic environments can modulate or augment gut microbiomes and improve host-microbe symbiosis, is being harnessed as an innovative approach to human health, one that may also have significant value to animal ... Full text Cite

Stephen E. Glickman

Chapter · November 29, 2022 Stephen E. Glickman (1933-2020) was an American comparative psychologist and scholar of the history of psychology, who contributed over 100 publications relevant to the study of animal behavior, cognitive and behavioral neuroscience, reproductive neuroendo ... Full text Cite

Meerkat manners: Endocrine mediation of female dominance and reproductive control in a cooperative breeder.

Journal Article Hormones and behavior · September 2022 This article is part of a Special Issue (Hormones and Hierarchies). To gain more balanced understanding of sexual selection and mammalian sexual differentiation processes, this review addresses behavioral sex differences and hormonal mediators of intrasexu ... Full text Cite

Gut microbiota of ring-tailed lemurs (Lemur catta) vary across natural and captive populations and correlate with environmental microbiota.

Journal Article Animal microbiome · April 2022 BackgroundInter-population variation in host-associated microbiota reflects differences in the hosts' environments, but this characterization is typically based on studies comparing few populations. The diversity of natural habitats and captivity ... Full text Cite

Integrating the female masculinization and challenge hypotheses: Female dominance, male deference, and seasonal hormone fluctuations in adult blue-eyed black lemurs (Eulemur flavifrons).

Journal Article Hormones and behavior · March 2022 In the decades since female social dominance was first described in strepsirrhine primates, researchers have sought to uncover the proximate and ultimate explanations for its development. In the females of various female-dominant species, androgens have be ... Full text Cite

Gut Microbial Diversity and Ecological Specialization in Four Sympatric Lemur Species Under Lean Conditions

Journal Article International Journal of Primatology · December 1, 2021 The gut microbiome is gaining recognition for its role in primate nutrition, but we stand to benefit from microbiome comparisons across diverse hosts and environmental conditions. We compared gut microbiome structure in four lemur species from four phyloge ... Full text Open Access Cite

An intergenerational androgenic mechanism of female intrasexual competition in the cooperatively breeding meerkat.

Journal Article Nature communications · December 2021 Female intrasexual competition can be intense in cooperatively breeding species, with some dominant breeders (matriarchs) limiting reproduction in subordinates via aggression, eviction or infanticide. In males, such tendencies bidirectionally link to testo ... Full text Cite

Antibiotics and fecal transfaunation differentially affect microbiota recovery, associations, and antibiotic resistance in lemur guts.

Journal Article Animal microbiome · October 2021 BackgroundAntibiotics alter the diversity, structure, and dynamics of host-associated microbial consortia, including via development of antibiotic resistance; however, patterns of recovery from microbial imbalances and methods to mitigate associat ... Full text Cite

Antibiotic Resistance Genes in Lemur Gut and Soil Microbiota Along a Gradient of Anthropogenic Disturbance

Journal Article Frontiers in Ecology and Evolution · August 9, 2021 The overuse of man-made antibiotics has facilitated the global propagation of antibiotic resistance genes in animals, across natural and anthropogenically disturbed environments. Although antibiotic treatment is the most well-studied route by which resista ... Full text Cite

Gut microbiota of frugo-folivorous sifakas across environments.

Journal Article Animal microbiome · May 2021 BackgroundCaptive animals, compared to their wild counterparts, generally harbor imbalanced gut microbiota owing, in part, to their altered diets. This imbalance is particularly striking for folivores that fundamentally rely on gut microbiota for ... Full text Cite

Neural correlates of mating system diversity: oxytocin and vasopressin receptor distributions in monogamous and non-monogamous Eulemur.

Journal Article Scientific reports · February 2021 Contemporary theory that emphasizes the roles of oxytocin and vasopressin in mammalian sociality has been shaped by seminal vole research that revealed interspecific variation in neuroendocrine circuitry by mating system. However, substantial challenges ex ... Full text Cite

Lack of evidence for pheromones in lemurs.

Journal Article Current biology : CB · November 2020 Featured Publication As chemicals that elicit unlearned, functionally specialized, and species-specific responses [1] or 'stereotyped behavior' [2], pheromones differ from mammalian scent signatures that comprise complex, variable mixtures, convey multiple messages via learned ... Full text Cite

Spotted hyaenas and the sexual spectrum: reproductive endocrinology and development.

Journal Article The Journal of endocrinology · October 2020 Featured Publication The spotted hyaena (Crocuta crocuta) is a unique species, even amongst the Hyaenidae. Extreme clitoral development in female spotted hyaenas challenges aspects of the accepted framework of sexual differentiation and reproductive function. They lack a vulva ... Full text Cite

A role for gut microbiota in host niche differentiation.

Journal Article The ISME journal · July 2020 Featured Publication If gut microbes influence host behavioral ecology in the short term, over evolutionary time, they could drive host niche differentiation. We explored this possibility by comparing the gut microbiota of Madagascar's folivorous lemurs from Indriidae and Lepi ... Full text Cite

Design, delivery and perception of condition-dependent chemical signals in strepsirrhine primates: implications for human olfactory communication.

Journal Article Philosophical transactions of the Royal Society of London. Series B, Biological sciences · June 2020 Featured Publication The study of human chemical communication benefits from comparative perspectives that relate humans, conceptually and empirically, to other primates. All major primate groups rely on intraspecific chemosignals, but strepsirrhines present the greatest diver ... Full text Cite

Stable and transient structural variation in lemur vaginal, labial and axillary microbiomes: patterns by species, body site, ovarian hormones and forest access.

Journal Article FEMS microbiology ecology · June 2020 Host-associated microbiomes shape and are shaped by myriad processes that ultimately delineate their symbiotic functions. Whereas a host's stable traits, such as its lineage, relate to gross aspects of its microbiome structure, transient factors, such as i ... Full text Cite

The importance of scale in comparative microbiome research: New insights from the gut and glands of captive and wild lemurs.

Journal Article American journal of primatology · October 2019 Research on animal microbiomes is increasingly aimed at determining the evolutionary and ecological factors that govern host-microbiome dynamics, which are invariably intertwined and potentially synergistic. We present three empirical studies related to th ... Full text Cite

Organizational and activational androgens, lemur social play, and the ontogeny of female dominance.

Journal Article Hormones and behavior · September 2019 The role of androgens in shaping "masculine" traits in males is a core focus in behavioral endocrinology, but relatively little is known about an androgenic role in female aggression and social dominance. In mammalian models of female dominance, including ... Full text Open Access Cite

Genetic variation at MHC class II loci influences both olfactory signals and scent discrimination in ring-tailed lemurs.

Journal Article BMC evolutionary biology · August 2019 BackgroundDiversity at the Major Histocompatibility Complex (MHC) is critical to health and fitness, such that MHC genotype may predict an individual's quality or compatibility as a competitor, ally, or mate. Moreover, because MHC products can inf ... Full text Cite

Local habitat, not phylogenetic relatedness, predicts gut microbiota better within folivorous than frugivorous lemur lineages.

Journal Article Biology letters · June 2019 Both host phylogenetic placement and feeding strategy influence the structure of the gut microbiome (GMB); however, parsing their relative contributions presents a challenge. To meet this challenge, we compared GMB structure in two genera of lemurs charact ... Full text Cite

Glandular microbiomes vary by species and host traits in wild and captive lemurs

Conference AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY · March 1, 2019 Link to item Cite

P-Mail: The Information Highway of Nocturnal, but Not Diurnal or Cathemeral, Strepsirrhines.

Journal Article Folia primatologica; international journal of primatology · January 2019 Scent marking is a well-established, but highly variable, mode of communication among strepsirrhine primates. We begin by reviewing this literature, focusing on nocturnal species. Our understanding about the information content of scent signals and the fac ... Full text Cite

Incidence and biomarkers of pregnancy, spontaneous abortion, and neonatal loss during an environmental stressor: Implications for female reproductive suppression in the cooperatively breeding meerkat.

Journal Article Physiology & behavior · September 2018 Meerkats are group-living, insectivorous herpestids in which subordinate members provide extensive care for the dominant female's young. In contrast to some cooperative breeders, subordinate female meerkats are physiologically able to reproduce and occasio ... Full text Cite

The critical role of dietary foliage in maintaining the gut microbiome and metabolome of folivorous sifakas.

Journal Article Scientific reports · September 2018 The gut microbiome (GMB) of folivores metabolizes dietary fiber into nutrients, including short-chain fatty acids (SCFAs); however, experiments probing the consequences of foliage quality on host GMBs are lacking. We therefore examined GMB structure and fu ... Full text Cite

Social and endocrine correlates of immune function in meerkats: implications for the immunocompetence handicap hypothesis.

Journal Article Royal Society open science · August 2018 Social status can mediate effects on the immune system, with profound consequences for individual health; nevertheless, most investigators of status-related disparities in free-ranging animals have used faecal parasite burdens to proxy immune function in t ... Full text Cite

Costs of injury for scent signalling in a strepsirrhine primate.

Journal Article Scientific reports · June 2018 Honesty is crucial in animal communication when signallers are conveying information about their condition. Condition dependence implies a cost to signal production; yet, evidence of such cost is scarce. We examined the effects of naturally occurring injur ... Full text Cite

Free-ranging access improves the gut microbiome of captive Eulemur

Conference AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY · April 1, 2018 Link to item Cite

Pee-mail: The information highway of nocturnal strepsirrhines

Conference AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY · April 1, 2018 Link to item Cite

Ontogeny of female dominance in ring-tailed lemurs: behavioral and hormonal evidence

Conference AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY · April 1, 2018 Link to item Cite

Hyenas

Chapter · January 1, 2018 The four, extant species of hyenids (aardwolves, striped hyenas, brown hyenas, and spotted hyenas) are compared and contrasted. Despite belonging to a small family of carnivorans, these species show a wide range of social systems (from solitary to gregario ... Full text Cite

Genetic wealth, population health: Major histocompatibility complex variation in captive and wild ring-tailed lemurs (Lemur catta).

Journal Article Ecology and evolution · October 2017 Across species, diversity at the major histocompatibility complex (MHC) is critical to individual disease resistance and, hence, to population health; however, MHC diversity can be reduced in small, fragmented, or isolated populations. Given the need for c ... Full text Cite

Social odours covary with bacterial community in the anal secretions of wild meerkats.

Journal Article Scientific reports · June 2017 The fermentation hypothesis for animal signalling posits that bacteria dwelling in an animal's scent glands metabolize the glands' primary products into odorous compounds used by the host to communicate with conspecifics. There is, however, little evidence ... Full text Cite

Condition-dependent Scent Signals in Strepsirrhine Primates

Conference AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY · April 1, 2017 Link to item Cite

In Sickness and In Health: Olfactory Cues of Injury and Illness in Lemurs

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · March 1, 2017 Link to item Cite

Down for the count: Cryptosporidium infection depletes the gut microbiome in Coquerel's sifakas.

Journal Article Microbial ecology in health and disease · January 2017 Background: The gut microbiome (GMB) is the first line of defense against enteric pathogens, which are a leading cause of disease and mortality worldwide. One such pathogen, the protozoan Cryptosporidium, causes a variety of digestive disorde ... Full text Cite

Androgens predict parasitism in female meerkats: a new perspective on a classic trade-off.

Journal Article Biology letters · October 2016 The immunocompetence handicap hypothesis posits that androgens in males can be a 'double-edged sword', actively promoting reproductive success, while also negatively impacting health. Because there can be both substantial androgen concentrations in females ... Full text Cite

Reproductive endocrine patterns and volatile urinary compounds of Arctictis binturong: discovering why bearcats smell like popcorn.

Journal Article Die Naturwissenschaften · June 2016 Members of the order Carnivora rely on urinary scent signaling, particularly for communicating about reproductive parameters. Here, we describe reproductive endocrine patterns in relation to urinary olfactory cues in a vulnerable and relatively unknown viv ... Full text Cite

Mix it and fix it: functions of composite olfactory signals in ring-tailed lemurs

Journal Article Royal Society Open Science · April 20, 2016 Animals communicating via scent often deposit composite signals that incorporate odorants from multiple sources; however, the function of mixing chemical signals remains understudied. We tested both a ‘multiple-messages’ and a ‘fixative’ hypothesis of comp ... Full text Open Access Link to item Cite

Next-generation genotyping of hypervariable loci in many individuals of a non-model species: technical and theoretical implications.

Journal Article BMC genomics · March 2016 BackgroundAcross species, diversity at the Major Histocompatibility Complex (MHC) is critical to disease resistance and population health; however, use of MHC diversity to quantify the genetic health of populations has been hampered by the extreme ... Full text Cite

Ring-tailed lemurs use olfactory signals to differentiate the MHC quality of potential mates

Conference AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY · March 1, 2016 Link to item Cite

Hormonal 'masculinization' in female meerkats (Suricata suricatta)

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · March 1, 2016 Link to item Cite

Beyond aggression: Androgen-receptor blockade modulates social interaction in wild meerkats.

Journal Article Hormones and behavior · February 2016 In male vertebrates, androgens are inextricably linked to reproduction, social dominance, and aggression, often at the cost of paternal investment or prosociality. Testosterone is invoked to explain rank-related reproductive differences, but its role withi ... Full text Cite

Patterns of parasitism in the cooperatively breeding meerkat: A cost of dominance for females

Journal Article Behavioral Ecology · January 1, 2016 Within animal societies, demographic and social factors, as well as the different reproductive efforts of group members, may influence individual patterns of reproductive success and parasitism. In mammals, such relationships have been studied primarily in ... Full text Cite

Female rule in lemurs is ancestral and hormonally mediated.

Journal Article Scientific reports · May 2015 Female social dominance (FSD) over males is unusual in mammals, yet characterizes most Malagasy lemurs, which represent almost 30% of all primates. Despite its prevalence in this suborder, both the evolutionary trajectory and proximate mechanism of FSD rem ... Full text Cite

Baby on board: olfactory cues indicate pregnancy and fetal sex in a non-human primate

Journal Article Biology Letters · February 25, 2015 Jeremy Chase Crawford1,2,3,4 and Christine M. Drea4,5⇑1National Evolutionary Synthesis Center, Durham, NC, USA2Department of Integrative Biology, University of California, Berkeley, CA, USA3Museum of Vertebrate Zoology, University of California, Berkeley, ... Full text Open Access Link to item Cite

D'scent of man: a comparative survey of primate chemosignaling in relation to sex.

Journal Article Hormones and behavior · February 2015 This article is part of a Special Issue (Chemosignals and Reproduction). As highly visual animals, primates, in general, and Old World species (including humans), in particular, are not immediately recognized for reliance in their daily interactions on olf ... Full text Cite

Socioecological and phylogenetic patterns in the chemical signals of strepsirrhine primates

Journal Article Animal Behaviour · November 1, 2014 Our understanding of chemical signals in mammals derives principally from studies in which researchers examine signal structure or function within a single species. Despite the unique information to be gained from applying comparable methods across multipl ... Full text Cite

Individual recognition through olfactory-auditory matching in lemurs.

Journal Article Proceedings. Biological sciences · June 2014 Individual recognition can be facilitated by creating representations of familiar individuals, whereby information from signals in multiple sensory modalities become linked. Many vertebrate species use auditory-visual matching to recognize familiar conspec ... Full text Cite

Reassessing Bateman: Sexual selection in strepsirrhine primates

Conference AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY · March 1, 2014 Link to item Cite

Love is in the air: Sociality and pair bondedness influence sifaka reproductive signalling

Journal Article Animal Behaviour · February 1, 2014 Social complexity, often estimated by group size, is seen as driving the complexity of vocal signals, but its relation to olfactory signals, which arguably arose to function in nonsocial realms, remains underappreciated. That olfactory signals also may med ... Full text Open Access Cite

Development of the external genitalia: perspectives from the spotted hyena (Crocuta crocuta).

Journal Article Differentiation; research in biological diversity · January 2014 This review/research paper summarizes data on development of the external genitalia of the spotted hyena, a fascinating mammal noted for extreme masculinization of the female external genitalia. The female spotted hyena is the only extant mammal that mates ... Full text Cite

Bacterial communities in meerkat anal scent secretions vary with host sex, age, and group membership

Journal Article Behavioral Ecology · January 1, 2014 The contribution of bacterial fermentation to the production of vertebrate scent signals has long been suspected, but there is still relatively little information about the factors driving variation in microbial composition in animal scent secretions. Our ... Full text Cite

Chemical differences between voided and bladder urine in the aye-aye (Daubentonia madagascariensis): implications for olfactory communication studies.

Journal Article American journal of primatology · July 2013 Urine serves a communicative function in many mammalian species. In some species, the signaling function of urine can be enhanced by the addition of chemical compounds from glands along the distal portion of the urogenital tract. Although urine marking is ... Full text Cite

The "secret" in secretions: methodological considerations in deciphering primate olfactory communication.

Journal Article American journal of primatology · July 2013 Olfactory communication in primates is gaining recognition; however, studies on the production and perception of primate scent signals are still scant. In general, there are five tasks to be accomplished when deciphering the chemical signals contained in e ... Full text Cite

Nasopalatine ducts and flehmen behavior in the mandrill: reevaluating olfactory communication in Old World primates.

Journal Article American journal of primatology · July 2013 Compared to other modes of communication, chemical signaling between conspecifics generally has been overlooked in Old World primates, despite the presence in this group of secretory glands and scent-marking behavior, as well as the confirmed production an ... Full text Cite

Victims of infanticide and conspecific bite wounding in a female-dominant primate: a long-term study.

Journal Article PloS one · January 2013 The aggression animals receive from conspecifics varies between individuals across their lifetime. As poignantly evidenced by infanticide, for example, aggression can have dramatic fitness consequences. Nevertheless, we understand little about the sources ... Full text Open Access Cite

Eulemur, me lemur: the evolution of scent-signal complexity in a primate clade.

Journal Article Philosophical transactions of the Royal Society of London. Series B, Biological sciences · July 2012 Signal complexity has been linked to social complexity in vocal, but not chemical, communication. To address this gap, we examined the chemical complexity of male and female glandular secretions in eight species of Eulemur. In this diverse clade of macrosm ... Full text Cite

Phylogenetic comparisons implicate sex hormone-binding globulin in "masculinization" of the female spotted hyena (Crocuta crocuta).

Journal Article Endocrinology · March 2012 Exposures to sex steroids during fetal development are thought to contribute to the unique urogenital anatomy and social dominance of the female spotted hyena: overt phenotypes not shared by other hyenids (i.e. striped hyena, brown hyena, and aardwolf). Be ... Full text Cite

How does cognition evolve? Phylogenetic comparative psychology.

Journal Article Anim Cogn · March 2012 Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly ... Full text Open Access Link to item Cite

Sight or scent: lemur sensory reliance in detecting food quality varies with feeding ecology.

Journal Article PloS one · January 2012 Visual and olfactory cues provide important information to foragers, yet we know little about species differences in sensory reliance during food selection. In a series of experimental foraging studies, we examined the relative reliance on vision versus ol ... Full text Cite

Nasopalatine ducts and flehmen behavior in the mandrill (Mandrillus sphinx): Reevaluating olfactory communication in primates.

Journal Article American Journal of Primatology · 2012 Compared to other modes of communication, chemical signaling generally has been overlooked in Old World primates, despite the presence in this group of secretory glands and scent-marking behavior, as well as the confirmed production and perception of consp ... Cite

Endocrine correlates of pregnancy in the ring-tailed lemur (Lemur catta): implications for the masculinization of daughters.

Journal Article Hormones and behavior · April 2011 Female ring-tailed lemurs (Lemur catta) are Malagasy primates that are size monomorphic with males, socially dominate males, and exhibit a long, pendulous clitoris, channeled by the urethra. These masculine traits evoke certain attributes of female spotted ... Full text Cite

Prospecting for urinary chemical signals in binturongs (Arctictis binturong)

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 27, 2011 Link to item Cite

The anti-androgen combination, flutamide plus finasteride, paradoxically suppressed LH and androgen concentrations in pregnant spotted hyenas, but not in males.

Journal Article General and comparative endocrinology · February 2011 The androgen receptor blocker flutamide and the 5α-reductase inhibitor finasteride have been used in a variety of species to investigate the ontogeny of sexual dimorphisms by treating pregnant females or neonates at critical periods of sexual differentiati ... Full text Cite

Night and day: the comparative study of strepsirrhine primates reveals socioecological and phylogenetic patterns in olfactory signals.

Journal Article Journal of evolutionary biology · January 2011 Studies of chemical signals in vertebrates typically target single species; however, a broader understanding of olfactory communication may derive from comparative studies. We collected urine from 12 species representing most families of strepsirrhine prim ... Full text Cite

Smelling wrong: Hormonal contraception in lemurs alters critical female odour cues.

Journal Article Proc Roy Soc, B · 2011 Animals, including humans, use olfaction to assess potential social and sexual partners. Although hormones modulate olfactory cues, we know little about whether contraception affects semiochemical signals and, ultimately, mate choice. We examined the effec ... Full text Cite

Honest olfactory ornamentation in a female-dominant primate.

Journal Article Journal of evolutionary biology · July 2010 Sexual selection theory predicts that potential mates or competitors signal their quality to conspecifics. Whereas evidence of honest visual or vocal signals in males abounds, evidence of honest signalling via scent or by females is scarce. We previously s ... Full text Cite

Mammalian chemical communication: Comparative investigation of urinary signals in prosimian primates

Journal Article ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 21, 2010 Link to item Cite

Seasonality, sociality, and reproduction: Long-term stressors of ring-tailed lemurs (Lemur catta).

Journal Article Hormones and behavior · January 2010 Fecal glucocorticoid (fGC) concentrations are reliable, non-invasive indices of physiological stress that provide insight into an animal's energetic and social demands. To better characterize the long-term stressors in adult members of a female-dominant, s ... Full text Cite

Message 'scent': lemurs detect the genetic relatedness and quality of conspecifics via olfactory cues

Journal Article Animal Behaviour · 2010 To enhance the fitness benefits of social and sexual interaction, animals should be able to decipher information about the genetic makeup of conspecifics. The use of relative criteria to estimate genetic relatedness could facilitate nepotism or inbreeding ... Full text Cite

Decoding an olfactory mechanism of kin recognition and inbreeding avoidance in a primate.

Journal Article BMC evolutionary biology · December 2009 BackgroundLike other vertebrates, primates recognize their relatives, primarily to minimize inbreeding, but also to facilitate nepotism. Although associative, social learning is typically credited for discrimination of familiar kin, discrimination ... Full text Open Access Cite

Cooperative problem solving in a social carnivore

Journal Article Animal Behaviour · October 1, 2009 Numerous field researchers have described cooperative hunting in social carnivores, but experimental evidence of cooperative problem solving typically derives from laboratory studies of nonhuman primates. We present the first experimental evidence of coope ... Full text Cite

Endocrine mediators of masculinization in female mammals

Journal Article Current Directions in Psychological Science · August 1, 2009 Most mammal species show traditional patterns of sexual dimorphism (e.g., greater male size and aggression), the proximal mechanism of which involves the male's greater pre- and postnatal exposure to circulating androgens. But in several species, females d ... Full text Cite

Seeing red: Behavioral evidence of trichromatic color vision in strepsirrhine primates

Journal Article Behavioral Ecology · January 12, 2009 Among primates, catarrhines (Old World monkeys and apes) and certain platyrrhines (New World monkeys) possess trichromatic color vision, which might confer important evolutionary advantages, particularly during foraging. Recently, a polymorphism has been s ... Full text Cite

Smelling right: the scent of male lemurs advertises genetic quality and relatedness.

Journal Article Molecular ecology · July 2008 Sexual selection theory predicts that competitors or potential mates signal their quality or relatedness to conspecifics. Researchers have focused on visual or auditory modes of signal transmission; however, the importance of olfactory indicators is gainin ... Full text Cite

External genital morphology of the ring-tailed lemur (Lemur catta): females are naturally "masculinized".

Journal Article Journal of morphology · April 2008 The extravagance and diversity of external genitalia have been well characterized in male primates; however, much less is known about sex differences or variation in female form. Our study represents a departure from traditional investigations of primate r ... Full text Cite

Inbreeding depression in ring-tailed lemurs (Lemur catta): Genetic diversity predicts parasitism, immunocompetence, and survivorship

Journal Article Conservation Genetics · January 1, 2008 The consequences of inbreeding have been well studied in a variety of taxa, revealing that inbreeding has major negative impacts in numerous species, both in captivity and in the wild; however, as trans-generational health data are difficult to obtain for ... Full text Cite

Chemical composition of scent marks in the ringtailed lemur (Lemur catta): glandular differences, seasonal variation, and individual signatures.

Journal Article Chemical senses · June 2007 The apocrine and sebaceous scent glands of ringtailed lemurs (Lemur catta) appear to serve different social functions. In behavioral experiments, lemurs modulate their responses to scent marks based on the type of odorant, their own physiological state, th ... Full text Cite

How to study socially biased learning in primates? Trends and future directions

Journal Article AMERICAN JOURNAL OF PRIMATOLOGY · June 1, 2007 Link to item Cite

Sex and seasonal differences in aggression and steroid secretion in Lemur catta: are socially dominant females hormonally 'masculinized'?

Journal Article Hormones and behavior · April 2007 Female social dominance characterizes many strepsirrhine primates endemic to Madagascar, but currently there is no comprehensive explanation for how or why female lemurs routinely dominate males. Reconstructing the evolutionary pressures that may have shap ... Full text Cite

Scents and sensibility: information content of olfactory signals in the ringtailed lemur, Lemur catta

Journal Article Animal Behaviour · February 1, 2007 The function of olfactory signalling in social species is less well understood than in asocial species. Consequently, we examined olfactory communication in the ringtailed lemur, a socially complex primate that retains a functional vomeronasal organ, has w ... Full text Cite

Mammalian sexual differentiation: lessons from the spotted hyena.

Journal Article Trends in endocrinology and metabolism: TEM · November 2006 Female spotted hyenas (Crocuta crocuta) are the only female mammals that lack an external vaginal opening. Mating and birth take place through a urogenital canal that exits at the tip of a hypertrophied clitoris. This 'masculine' phenotype spurred a search ... Full text Cite

Studying primate learning in group contexts: Tests of social foraging, response to novelty, and cooperative problem solving.

Journal Article Methods (San Diego, Calif.) · March 2006 Learning commonly refers to the modification of behavior through experience, whereby an animal gains information about stimulus-response contingencies from interacting with its physical environment. Social learning, on the other hand, occurs when the same ... Full text Cite

Morphological and hormonal correlates of 'masculinization' in ringtailed lemurs (Lemur catta).

Journal Article AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY · January 1, 2006 Link to item Cite

Sex-specific variation in ringtailed lemur Lemur catta olfactory communication

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · December 1, 2005 Link to item Cite

Could female ringtailed lemurs be masculinized by maternal androgens?

Conference INTEGRATIVE AND COMPARATIVE BIOLOGY · December 1, 2005 Link to item Cite

Bateman revisited: the reproductive tactics of female primates.

Journal Article Integrative and comparative biology · November 2005 The breeding system of an animal population is thought to depend on the ability of one sex (usually the male) to acquire mates, either directly through association with females or indirectly through defense of the resources desired by females. The sex that ... Full text Cite

The social complexity of spotted hyenas

Conference ANIMAL SOCIAL COMPLEXITY · January 1, 2003 Link to item Cite

Responses to olfactory stimuli in spotted hyenas (Crocuta crocuta): I. Investigation of environmental odors and the function of rolling.

Journal Article Journal of comparative psychology (Washington, D.C. : 1983) · December 2002 Olfaction is crucial to spotted hyenas (Crocuta crocuta), yet there are no controlled studies of their reactions to odors. In Experiment 1, the authors examined responses of captive hyenas to various environmental (prey, nonprey animal, and plant) odors. S ... Full text Cite

Effects of prenatal treatment with antiandrogens on luteinizing hormone secretion and sex steroid concentrations in adult spotted hyenas, Crocuta crocuta.

Journal Article Biology of reproduction · November 2002 Prenatal androgen treatment can alter LH secretion in female offspring, often with adverse effects on ovulatory function. However, female spotted hyenas (Crocuta crocuta), renowned for their highly masculinized genitalia, are naturally exposed to high andr ... Full text Cite

Exposure to naturally circulating androgens during foetal life incurs direct reproductive costs in female spotted hyenas, but is prerequisite for male mating.

Journal Article Proceedings. Biological sciences · October 2002 Among all extant mammals, only the female spotted hyena (Crocuta crocuta) mates and gives birth through the tip of a peniform clitoris. Clitoral morphology is modulated by foetal exposure to endogenous, maternal androgens. First births through this organ a ... Full text Cite

Responses to olfactory stimuli in spotted hyenas (Crocuta crocuta): II. Discrimination of conspecific scent

Journal Article Journal of Comparative Psychology · 2002 Scent marking in spotted hyenas (Crocuta crocuta) includes the deposition of anal sac secretions, or “paste,” and presumably advertises territorial ownership. To test whether captive hyenas classify and discriminate individuals using odor cues in paste ... Full text Cite

Low-status monkeys "play dumb" when learning in mixed social groups.

Journal Article Proceedings of the National Academy of Sciences of the United States of America · October 1999 Many primates, including humans, live in complex hierarchical societies where social context and status affect daily life. Nevertheless, primate learning studies typically test single animals in limited laboratory settings where the important effects of so ... Full text Cite

Status, age, and sex effects on performance of discrimination tasks in group-tested rhesus monkeys (Macaca mulatta).

Journal Article Journal of comparative psychology (Washington, D.C. : 1983) · June 1998 To assess the relation between performance and social or demographic variables, this study group tested a captive monkey colony on visual and manual discrimination problems. Animals could choose between differently colored, sand-filled boxes, where hue sig ... Full text Cite

Androgens and masculinization of genitalia in the spotted hyaena (Crocuta crocuta). 2. Effects of prenatal anti-androgens.

Journal Article Journal of reproduction and fertility · May 1998 Pregnant spotted hyaenas were treated with anti-androgens to interfere with the unusually masculine 'phallic' development that characterizes females of this species. The effects on genital morphology and plasma androgen concentrations of infants were studi ... Full text Cite

Androgens and masculinization of genitalia in the spotted hyaena (Crocuta crocuta). 3. Effects of juvenile gonadectomy.

Journal Article Journal of reproduction and fertility · May 1998 Studies involving the administration of anti-androgens to spotted hyaenas during fetal development have raised questions concerning the precise contributions of steroids to phallic growth in these animals. If gonadal androgens promote postnatal penile grow ... Full text Cite

Social context affects how rhesus monkeys explore their environment

Journal Article American Journal of Primatology · 1998 This study reports on social modulation of exploratory behavior and response to novelty by members of a captive rhesus monkey colony. The group was trained to split in half, with one subgroup composed of dominant members only, the other of subordinate ... Full text Cite

Social context affects how rhesus monkeys explore their environment.

Journal Article American journal of primatology · January 1998 This study reports on social modulation of exploratory behavior and response to novelty by members of a captive rhesus monkey colony. The group was trained to split in half, with one subgroup composed of dominant members only, the other of subordinates. Th ... Full text Cite

The emergence of affiliative behavior in infant spotted hyenas (Crocuta crocuta).

Journal Article Annals of the New York Academy of Sciences · January 1997 Full text Cite

Social facilitation, affiliation, and dominance in the social life of spotted hyenas.

Journal Article Annals of the New York Academy of Sciences · January 1997 Full text Cite

Primate Handedness: An Emerging Discipline?

Journal Article Contemporary Psychology: A Journal of Reviews · July 1996 Full text Cite

Aggression decreases as play emerges in infant spotted hyaenas: Preparation for joining the clan

Journal Article Animal Behaviour · January 1, 1996 The early social development of spotted hyaenas, Crocuta crocuta, is marked by a dramatic transition at 2-3 weeks of age, when infants are taken from the isolation of their natal den, where they are intensely aggressive, to the communal den, where they mee ... Full text Cite

Neonatal testosterone and handedness in yearling rhesus monkeys (Macaca mulatta).

Journal Article Physiology & behavior · December 1995 This study investigated the relationship between neonatal testosterone (T) and hand bias in young rhesus monkeys (Macaca mulatta). Subjects (n = 8 per group) included: neonatally androgen-suppressed males, using a Nal-Lys gonadotropin releasing hormone (Gn ... Full text Cite

Gradual acquisition of visual discrimination tasks in a social group of rhesus monkeys (Macaca mulatta)

Journal Article Animal Learning & Behavior · March 1, 1995 An established, captive colony of 74 rhesus monkeys (Macaca mulatta) was group-tested on a simultaneous visual discrimination problem and three reversals of the initial discrimination. The task incorporated important aspects of rhesus foraging behavior. Al ... Full text Cite

Asymmetrical hand use in rhesus monkeys (Macaca mulatta) in tactually and visually regulated tasks.

Journal Article Journal of comparative psychology (Washington, D.C. : 1983) · September 1991 Asymmetrical hand use by rhesus monkeys (Macaca mulatta) was investigated in a series of tactually and visually guided tasks. The 1st experiment recorded manual preferences of 29 monkeys for solving a haptic discrimination task in a hanging posture. There ... Full text Cite

Asymmetrical hand use in rhesus monkeys (Macaca mulatta) in tactually and visually regulated tasks.

Journal Article Journal of comparative psychology (Washington, D.C. : 1983) · 1991 Asymmetrical hand use by rhesus monkeys (Macaca mulatta) was investigated in a series of tactually and visually guided tasks. The 1st experiment recorded manual preferences of 29 monkeys for solving a haptic discrimination task in a hanging posture. There ... Full text Cite

Polyol and vacuole formation in cultured canine lens epithelial cells.

Journal Article Experimental eye research · May 1989 Polyol accumulation and myo-inositol depletion were accompanied by extensive vacuole formation in cultured canine lens epithelial cells that were incubated for up to 96 hr in growth medium supplemented with 30 mM D-galactose or 30 mM D-glucose. These chang ... Full text Cite

Age-related alterations in vitamin A metabolism in the rat retina.

Journal Article Experimental eye research · June 1987 Vitamin A plays a central role in visual transduction and in maintaining the structural integrity of the retina. It is possible that age-related alterations in vitamin A metabolism in the eye could contribute to the impairment of visual function that occur ... Full text Cite

Dietary vitamins A and E influence retinyl ester composition and content of the retinal pigment epithelium.

Journal Article Biochimica et biophysica acta · June 1987 Experiments were conducted to determine the influence of dietary levels of vitamin A and alpha-tocopherol on the amounts and composition of retinyl esters in the retinal pigment epithelium of light-adapted albino rats. Groups of rats were fed diets contain ... Full text Cite

Influence of early photoreceptor degeneration on lipofuscin in the retinal pigment epithelium.

Journal Article Experimental eye research · October 1986 Experiments were conducted to evaluate the role played by photoreceptor cells in the accumulation of age pigment, or lipofuscin, in the retinal pigment epithelium (RPE). The age-related accumulation of RPE lipofuscin was compared between rats with heredita ... Full text Cite

Relationship between dietary retinol and lipofuscin in the retinal pigment epithelium.

Journal Article Mechanisms of ageing and development · August 1986 A variety of evidence suggests that autoxidation of cellular components probably plays a significant role in the age-related accumulation of lipofuscin, or age-pigment, in the mammalian retinal pigment epithelium (RPE). Among the likely candidates for conv ... Full text Cite