Increased behavioural lateralization in parasitized coral reef fish

Preferential use of one side of the body for cognitive or behavioural tasks (lateralization) is common in many animals, including humans. However, few studies have demonstrated whether lateralization is phenotypically plastic, and varies depending on the ecological context. We studied lateralization (measured as a turning preference) in the bridled monocle bream (Scolopsis bilineatus). This coral reef fish is commonly infected by a large, ectoparasitic isopod (Anilocra nemipteri) that attaches to the left or right side of its host’s head. Fish that were parasitized showed no turning bias with respect to the side on which the parasite had attached. On average, however, parasitised fish were significantly more lateralized (i.e. had a strong side bias) than unparasitized fish. The extent of lateralization declined significantly when we experimentally removed the parasite. Our results indicate that lateralization can vary with the ecological context. One possible explanation is that lateralization shortens the response time until fish flee after encountering a predator. A stronger side bias might be advantageous for parasitized individuals to overcome their recently documented lower maximum swimming speed.     

Offspring number in pygmy marmosets, Cebuella pygmaea *, in relation to group size and the number of adult males

In many species of birds and mammals with a co-operative breeding and rearing system, offspring survival is positively related to the number of helpers. In the New World callitrichine primates (marmosets and tamarins), adult males are considered as particularly valuable helpers, and female reproductive success may depend strongly on the males' contribution to infant care. We analysed the number of offspring (infants, juveniles) in groups of wild pygmy marmosets, Cebuella pygmaea (Callitrichinae, Cebidae, Primates), in relation to the number of adult males and to the number of adult and subadult group members. In contrast to other callitrichines with a co-operative system of infant care, no relationship was found between the number of adult males and the number of infants and offspring. However, there was a significant positive relationship between the number of juveniles and the number of adult and subadult group members. The lack of a relationship between infant and adult-male number is interpreted as resulting from the reduced importance of adult males as helpers in pygmy marmosets in comparison to other callitrichines, probably due to the reduced costs of infant care. The relationship between the number of juveniles and the number of adult and subadult group members is in accordance with increased offspring survival in larger groups, as observed in other primates. Received: 1 February 1999 / Received in revised form: 5 June 1999 / Accepted: 29 June 1999     

Males as infant protectors in Hanuman langurs (Presbytis entellus) living in multimale groups – defence pattern, paternity and sexual behaviour

Hypotheses about the evolution of gregariousness and social organisation in primates are based on ecological explanations as well as on social factors such as conspecific threat (especially infanticide by males). The social explanation fits well with the conditions found in strepsirrhine primates and furthermore explains why infanticide in anthropoid primates living in one-male groups mainly occurs when the resident male (protector) is replaced. However, whether it likewise fits to the conditions in multimale groups will depend on the role of resident males as infant protectors, which has rarely been examined. We investigated long-term data of wild Hanuman langurs (Presbytis entellus) inhabiting a forest near the village of Ramnagar (southern Nepal). Twenty-two eye-witnessed attacks on infants by males were analysed in connection with male residency, paternity (DNA analyses) and sexual behaviour. Adult males played a major role in infant defence (65%). Only the genetic father or males who had been residents when the infant was conceived were observed to protect infants. Males who immigrated after a female had conceived may later attack her infant and were never observed to defend it. lt seems that the males took only copulations with potentially fertile females but not with pregnant females as clues for paternity. In the light of these results it seems likely that the risk of infanticide is an important determinant in female-male associations even in anthropoid primate multimale groups. Received: 22 December 1998 / Received in revised form: 30 April 1999 / Accepted: 1 May 1999     

“Friendships” between new mothers and adult males: adaptive benefits and determinants in wild baboons (<Emphasis Type="Italic">Papio cynocephalus</Emphasis>)

Close associations between adult males and lactating females and their dependent infants are not commonly described in non-monogamous mammals. However, such associations [sometimes called “friendships” (Smuts 1985)] are regularly observed in several primate species in which females mate with multiple males during the fertile period. The absence of mating exclusivity among “friends” suggests that males should invest little in infant care, raising questions about the adaptive significance of friendship bonds. Using data from genetic paternity analyses, patterns of behavior, and long-term demographic and reproductive records, we evaluated the extent to which friendships in four multi-male, multi-female yellow baboon (Papio cynocephalus) groups in Amboseli, Kenya represent joint parental care of offspring or male mating effort. We found evidence that mothers and infants benefited directly from friendships; friendships provided mother–infant dyads protection from harassment from other adult and immature females. In addition, nearly half of all male friends were the genetic fathers of offspring and had been observed mating with mothers during the days of most likely conception for those offspring. In contrast, nearly all friends who were not fathers were also not observed to consort with the mother during the days of most likely conception, suggesting that friendships between mothers and non-fathers did not result from paternity confusion. Finally, we found no evidence that prior friendship increased a male’s chances of mating with a female in future reproductive cycles. Our results suggest that, for many male–female pairs at Amboseli, friendships represented a form of biparental care of offspring. Males in the remaining friendship dyads may be trading protection of infants in exchange for some resources or services not yet identified. Our study is the first to find evidence that female primates gain social benefits from their early associations with adult males. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Sexual conflict in a polygynous primate: costs and benefits of a male-imposed mating system

Fundamental reproductive interests dictate that females generally benefit most from mate selectivity and males from mate quantity. This can create conflict between the sexes and result in sexual coercion: male use of aggression to garner mating success at a cost to females. Potential fitness costs of sexual coercion, however, can be difficult to measure. Here, we demonstrate benefits to males and costs to females of female defense polygyny in wild hamadryas baboons, cercopithecoid primates in which females are coercively transferred among social units by males, restricting both female choice and bonding among female kin. Of all coercive transfers (takeovers) of females with young infants, 67 % were followed by infant mortality, which was significantly more likely to occur after takeovers than at other times. As expected, infant mortality decreased time to subsequent conception but lengthened intervals between surviving infants. Following infant survival, whether a female had experienced a takeover after the previous birth was a significant predictor of subsequent interbirth interval, with interbirth intervals of females remaining with the same male between births being significantly shorter than those of females incurring takeovers between births. Together, these results reveal that takeovers increase the chance of infant mortality while delaying subsequent conception. Male-driven female defense polygyny in this species is thus costly to females in two ways. These results demonstrate that reproductive strategies benefitting males can evolve despite substantial costs to females. These costs may be mitigated over the long term, however, by female counterstrategies and protective behavior by males.     

Infant parking and nesting, not allomaternal care, influence Malagasy primate life histories

Allomaternal care is a rare, though phylogenetically widespread, mammalian infant care strategy. Among primates, the effects of allomaternal care are marked; its presence correlates with faster infant growth, younger age at weaning, and shorter interbirth intervals. Recent comparative research has found that such fertility benefits are absent in other mammals and are thus unique to primates. In large part because data describing lemur allomaternal care were lacking, the reproductive advantages of allomaternal care have never been demonstrated in Malagasy strepsirrhines. Using newly available data and rigorous phylogenetic methods, we extend this hypothesis to strepsirrhines and test whether allomaternal care in lemurs confers similar maternal reproductive benefits. Contrary to expectations, the presence of allomaternal care did not significantly impact lemur reproductive output; we did not find relationships between allomaternal care and either fetal or postnatal growth rates or interbirth intervals. Rather, infant parking and nesting, strategies employed primarily by litter-bearing species, were positively associated with faster fetal and postnatal infant growth, while nesting was negatively associated with interbirth interval. Thus, although each form of haplorrhine allomaternal care is also observed in Malagasy primates, the effects that these behaviors have on female reproductive output more closely resemble nonprimate mammals. We suggest that Malagasy strepsirrhines may not equally benefit from allomaternal care compared to haplorrhines because reproductive rates are less flexible and allomaternal care may instead increase infant survival in Madagascar’s harsh and unpredictable environment. Our study has significant implications for understanding the evolution of infant care and developmental trajectories in mammals.     

Male takeover,infanticide, and female countertactics in white-headed leaf monkeys (<Emphasis Type="Italic">Trachypithecus leucocephalus</Emphasis>)

Infanticide by males is common in mammalian species such as primates in which lactation lasts much longer than gestation. It frequently occurs in one-male groups following male takeovers and is likely a male reproductive strategy. Reported female countertactics include abrupt weaning of infants, dispersal, or paternity confusion. Here, we estimated costs of female countertactics in terms of weaning ages and interbirth intervals. We observed a population of white-headed leaf monkeys (Trachypithecus leucocephalus) in Nongguan Nature Reserve, China (1995–2006) mainly composed of one-male groups. Takeovers (N = 11) coincided with the peak conception period. Detailed data are presented for five takeovers (34 females, 29 infants, and 47 group-years) leading to six infant disappearances (42.9% of infant mortality). All presumed infanticides were in accordance with the sexual selection hypothesis. Following a takeover, females without infants or with old infants stayed with the new males, incurring no or low costs (via abrupt weaning). Females with young infants dispersing with the old males also experienced low costs. High costs (due to infant loss) were incurred by pregnant females and those with young infants who stayed with the new males indicating that paternity was not confused. Costs in terms of long interbirth intervals were also high for females leaving with the old males to later join the new males, despite infant survival. Female countertactics reflected female philopatry mediated by infant age. Presumably due to the seasonal timing of takeovers, most countertactics seemed successful given that 32.3% of females apparently incurred no costs and 41.2% incurred only low costs.     

Infant handling by female Barbary macaques (Macaca sylvanus) at Affenberg Salem: testing functional and evolutionary hypotheses

Assisting the genetic parents in the rearing of young, a widespread phenomenon in many birds and mammals, is usually regarded as an altruistic or mutualistic behavior. Infant handling by females other than the mother is also common in many primates, but due to high within- and between-species variation and limited knowledge about fitness consequences there is no consensus about its evolutionary and functional significance. Analysis of female infant-handling patterns and its reproductive consequences in three groups of semifree-ranging Barbary macaques revealed that nulliparous females significantly more often handled infants than parous females, but infant handling experience did not affect survival of their own first live-born offspring. Females interacted preferentially with closely related infants, but infant handling frequency improved neither infant survival nor maternal fecundity. Reciprocation of infant handling by mothers was rare. Although “aunting to death” occurred in the population, the hypothesis that infant handling serves to reduce the fitness of competitors was not supported. Limited evidence suggests that females at least sometimes use infants as strategic tools in the course of alliance formation. In concert with this poor evidence for a functional basis of the behavior, several lines of evidence support the hypothesis that infant handling evolved as a non-adaptive by-product of a strong selection for mother-offspring bonding. (1) Rates of infant handling were highest among females that experienced early infant loss. (2) Females caring for infants or yearlings of their own handled other infants significantly less often than females without dependent offspring. (3) Infant handling by females was most prevalent during the infants’ first month of life. (4) Both “aunting to death” and a successful adoption occurred irrespective of kinship relations. Although the by-product hypothesis appears to be the only one able to explain all results of this study, the apparent rarity of infant handling in non-female-bonded species suggest that kin selection is a possible alternative explanation for the evolution of female infant-handling in primates. Received: 30 December 1995/Accepted after revision: 10 May 1996     

Predatory behavior of crowned hawk-eagles (Stephanoaetus coronatus) in Kibale National Park, Uganda

Evaluating the nature and significance of predation on populations of wild primates has been difficult given a paucity of data regarding the phenomenon. Here we addressed this problem in a 37-month study of the predatory behavior of crowned hawk-eagles living at the Ngogo study site in Kibale National Park, Uganda. We collected prey remains underneath the nests of two pairs of eagles and census data on potential prey species to investigate prey selection and the ecological impact of predation on the Ngogo primate population. Results indicate that primates form the vast majority of all prey items. Eagles prey selectively on monkeys according to sex and species. Male primates were taken more often than females, while two species, redtail monkeys and mangabeys, were captured significantly more and less, respectively, than chance expectation. In addition, there was no bias in the age of prey: adult and non-adults were killed in numbers roughly equal to their proportional representations in the forest. Further analyses indicate that a non-trivial fraction of the entire primate population at Ngogo succumbs to crowned hawk-eagle predation each year. These results reveal both parallels and contrasts with those reported previously. Some of the parallels are due to similarities in prey availability, while contrasts are likely related to methodological differences between studies, inter- individual variations in predator hunting styles, and differences in prey abundance, demography, and behavior. Received: 29 March 2000 / Revised: 6 June 2000 / Accepted: 15 October 2000     

Multi-year lactation and its consequences in Bornean orangutans (Pongo pygmaeus wurmbii)

In most mammals, females pay for reproduction by dramatically increasing net energy intake from conception to mid- or late lactation. To do this, they time their reproductive events in relation to environmental cycles so that periods of peak food availability coincide with peak demand or are used to build energy stores. This timing is not possible in species with slow development in which lactation is prolonged over a multi-year period with fluctuating food availability. Here, mothers are expected to sustain a stable but generally lower level of nutrient transfer. In a sample of over 1,050 complete follow days of eight mother–infant pairs collected over 7 years, we document maternal effort for wild Bornean orangutans (Pongo pygmaeus wurmbii) over their average 6.5-year lactation period. As predicted, maternal feeding time was independent of the age of her growing offspring, indicating a stable sustained “plateau” effort of ≤ 25 % above baseline level, instead of a short peak lactation as seen in seasonal breeders. Infant orangutans started to regularly supplement milk with self-harvested food when they were 1–1.5 years old, indicating milk intake was insufficient from this age onwards, even though maternal effort did not decrease. We expect the same regulation of sustained maternal effort in other large and large-brained mammals with slow infant development. We also predict that mother–infant conflict over suckling may show another peak at the onset of the milk?+?solid food phase, in addition to the well-known conflict around the endpoint of lactation (weaning), which is reached after a long and gradual increase in solid food intake by the infant.     

Social experience during adolescence influences how male zebra finches (Taeniopygia guttata) group with conspecifics

Group-living animals rely on social skills which ensure beneficial interaction and prevent harmful ones with conspecifics. In a previous experiment, we demonstrated that male zebra finches reared in groups during adolescence show consistently less courtship and aggressive behaviour as adults than pair-reared males. Here we tested whether such differences affect how they group with conspecifics, as an indicator of their social integration. Zebra finches were kept in pairs (male–female or male–male) or mixed-sex groups (three males and three females) during adolescence and were introduced to an established group of unknown conspecifics during adulthood. Male courtship and aggressive behaviour were quantified directly after introduction to the group and 48 h later. At the same time, male position in relation to other birds and the number of birds in proximity were recorded. Males that grew up in a small mixed-sex group during adolescence spent more time within groups, were observed in bigger groups and lost less weight than males raised in pairs, indicating that an enriched social environment during early development may facilitate social integration. However, we observed no differences in courtship and aggressive behaviour that could predict the differences in grouping behaviour of pair- and group-reared males. We discuss alternative explanations for the difference in grouping and how to test these in future research.     

Variation in behavioral and hormonal responses of adult male gray-cheeked mangabeys (<Emphasis Type="Italic">Lophocebus albigena</Emphasis>) to crowned eagles (<Emphasis Type="Italic">Stephanoaetus coronatus</Emphasis>) in Kibale National Park,Uganda

Intensive study of arboreal forest-dwelling primates and their predators in Africa is increasingly revealing that crowned eagles (Stephanoaetus coronatus) are major predators of primates. Gray-cheeked mangabeys (Lophocebus albigena) are overrepresented in the diets of crowned eagles in Kibale National Park, Uganda, and adult male mangabeys are represented more than females. We focused on the behavior of adult male gray-cheeked mangabeys living in social groups in Kibale National Park (1) to clarify the interactions between mangabeys and eagles that might put adult males at greater risk and (2) to better understand individual variation in behavioral responses to predators. Adult male mangabeys in five groups responded to observer-confirmed presence of crowned eagles 88 times over a 13-month period. While all males gave alarm calls, only the highest-ranking male in each of four groups chased eagles. These males had elevated levels of fecal cortisol metabolites in the days immediately after they engaged in active defense, suggesting that they perceived such behavior as risky. In the one group where male ranks were unstable and there were no infants, no male was observed to chase eagles. We suggest that males pursue the dangerous tactic of chasing eagles only when they are likely to have offspring in the group. Males in larger groups also spent less time alarm calling to crowned eagles (from first to last call in a group), and our observations confirmed that the duration of their alarm calls was related to eagle presence. Thus, eagles spent less time around larger mangabey groups. Alarm calling by adult male mangabeys may signal to this ambush predator that it has been detected and should move on.     

Tutor choice and imitation accuracy during song learning in a wild population of the Puget Sound white-crowned sparrow

Songbirds learn to sing by modeling their songs on the songs of other males through a process of social learning. Models of social learning predict that animals should be selective in what and when they learn. In this study, we asked whether young males in a wild population of the Puget Sound white-crowned sparrow, Zonotrichia leucophrys pugetensis, were selective in their choice of tutor models and what factors influenced how accurately they imitated tutors’ songs. We first examined two strategies for tutor choice: whether pupils have a conformity bias and/or a preference for high-quality tutors. In keeping with a conformity bias, tutors that sang song types that were relatively common within a radius of about 500 m of their territory were more likely to be imitated than were tutors that sang rarer song types. Most potential tutors were not imitated by pupils. Aspects of tutor quality, such as age, pairing status, and survival to the next year had no effect on whether a tutor’s song was imitated. Secondly, we tested whether pupil repertoire size, pupil quality, and local abundance of tutor models affected the accuracy of song imitations. We found a trade-off between repertoire size and tutor imitation accuracy with males that sang two or more song types developing significantly poorer imitations than males that sang one type. We discuss possible functions of a conformity learning strategy and factors that could produce a trade-off between imitation accuracy and repertoire size.     

Infant handling and mortality in yellow baboons (<Emphasis Type="Italic">Papio cynocephalus</Emphasis>): evidence for female reproductive competition?

This study examines negative and positive infant handling behavior in 24 free-ranging yellow baboon infants (Papio cynocephalus) studied over a 5-year period in Mikumi National Park, Tanzania. We test predictions of the female reproductive competition hypothesis to explain patterns of infant handling behavior by adult females (excluding the infants mother) in relation to observed cases of infant mortality by age 3 months (25% of infants in this study). Results show that: (1) low-ranking infants received more negative infant handling than high-ranking infants; conversely high-ranking infants received more positive infant handling; (2) female kin engaged in higher levels of positive infant handling than did non-kin, whereas non-kin showed higher levels of negative infant handling; (3) rates of negative infant handling varied by season, with high levels at the onset of the rainy season; and (4) high level of negative infant handling was a significant predictor of infant mortality by age 3 months (infant rank and sex did not predict survival). We discuss how the occurrence and interpretation of infant handling behavior in the literature has likely been confused by different definitions of this behavior, as well as differences in the socio-ecological context in which this behavior occurs.Communicated by C. Nunn     

Delayed juvenile dispersal and monogamy, but no cooperative breeding in white-breasted mesites (Mesitornis variegata)

Although cooperative breeding is known from only about 9 % of bird species, it has received substantial attention because individuals foregoing their own reproduction to help others represent a long-standing evolutionary puzzle. We studied group formation, breeding system, spatial distribution and several life-history traits of white-breasted mesites (Mesitornis variegata). Based on field observations across 3 years, we found that white-breasted mesites live in year-round stable pairs, and that groups are formed by juvenile philopatry. As other family-living birds, M. variegata exhibit a slow pace-of-life, characterized by high annual adult survival, low productivity, long chick dependence and extended parental care. However, although reproduction is monogamous and juveniles showed interest in their parents’ nests, we found no evidence of cooperative breeding. We suggest that slow life-histories, extended parental care and year-round territoriality predispose juvenile mesites to delay dispersal. However, adult intolerance toward older juveniles may prevent them from adopting a cooperative lifestyle. Comparisons with other species of mesite indicate that monogamy and delayed juvenile dispersal are necessary, but not sufficient for the evolution of cooperative breeding in this family of birds, and that particular ecological and social conditions have facilitated the transition from pair-living to a type of group that may represent a stepping stone in the evolution of cooperative breeding in mesites and other birds.     

Communal nesting, kinship, and maternal success in a social primate

Communal nesting, where several mothers regularly pool and cooperatively rear offspring, is unusual in mammals. This type of crèching behavior is especially rare among primates, with the notable exceptions of humans, some nocturnal strepsirrhines, and—as we show in this study—black-and-white ruffed lemurs (Varecia variegata). Here, we combine data on nesting behavior, genetic relatedness, and infant survivorship to describe variation in ruffed lemur infant care and to examine the potential benefits of ruffed lemur communal breeding. Reproductive events were rare, and females produced litters (synchronously) only once in 6 years of observation. We show that not all mothers participate in communal crèches, but those that did had greater maternal success; communal breeders spent more time feeding and their offspring were more likely to survive. Although cooperating mothers were often related, females also cooperated with non-kin, and those who shared infant care responsibilities had greater maternal success than mothers who did not participate. If there is indeed a causal link between maternal cooperation and reproductive success, this unusual behavior, like that of human communal rearing, may have evolved via some combination of kin selection and mutualism.     

High rates of extra-pair young in the pair-living fat-tailed dwarf lemur, Cheirogaleus medius

Cheirogaleids are one of the most primitive extant primate taxa in the world. Their lifestyle and mating system, therefore, have been considered to be representative for social systems in primate ancestors. Accepted models of social evolution in primates state that pair-bonding has evolved secondarily from diurnal group-living taxa and should therefore be constrained primarily to diurnal species. In contrast to these assumptions, the nocturnal fat-tailed dwarf lemur (Cheirogaleus medius) lives in permanent pairs, with obligate paternal care probably representing the evolutionary basis of pair-living. In this sociobiological field study, we analyzed the reproduction strategy of C. medius in the tropical forest of western Madagascar. In the rainy seasons from 1995 to 1999, 173 individuals of C. medius were captured and individually marked and 131 were genetically characterized through seven microsatellite loci. Additionally, 36 of these individuals were radio-tracked and observed. For 53 genotyped individuals, including 16 offspring, information about pair-bonding and family structure was known from field observations. Genetic analyses revealed that yearlings and infants living with an adult pair were in all cases sibs of the social mother. However, C. medius does not restrain from extra-pair copulations (EPCs) and a high rate of extra-pair paternity (44%) was detected. Males sired offspring with their female partners as well as with extra-pair females within the same year, indicating that males may increase their reproductive success by EPCs without necessarily running the risk of cuckoldry. Females on the other hand do not seem to run the risk of reduced paternal care, either because males cannot detect relatedness of young, or because they might even increase their inclusive fitness by raising offspring of closely related males. Since females reproduce preferentially with territory holders and no paternity could be assigned to floating males, superior genetic quality of the males might be crucial for female choice. Received: 12 January 2000 / Revised: 15 August 2000 / Accepted: 26 August 2000     

The evolution of non-maternal caretaking among anthropoid primates: do helpers help?

Non-maternal infant care among nonhuman primates has frequently been investigated from the perspective of the caretaker. Here we examine whether allocaretaking behavior provides direct reproductive benefits to mothers. Comparative analyses that control for the effects of allometry and phylogeny reveal that allocaretaking behavior correlates with relatively fast infant growth and reproduction, but is not associated with the production of large infants. These results are consistent with those from studies of other taxa; primate helpers appear to increase the reproductive success of female breeders. In addition, our findings contrast with those derived from traditional allometric analyses and underscore the importance of controlling for the potentially confounding effects of phylogeny in comparative analyses. Received: 28 May 1996 / Accepted after revision: 16 November 1996     

The false limpet Siphonaria gigas, a simultaneous hermaphrodite, lives in pairs in rock fissures on the Pacific coast of Panama

The pulmonate limpet Siphonaria gigas, a simultaneous hermaphrodite, lives in the mid- to upper-intertidal zone on rocky shores in the tropical Eastern Pacific. Samples along five transects taken in June–July, 2004, on Culebra Point (8º54′N to 79º31′W), Republic of Panama, showed that 71 % of the population occurred in fissures, a significant preference for this habitat. Of 200 adults in 27 fissures, 150 lived side by side in pairs with their shells touching or nearly so, a significant deviation from the number of pairs expected given a random arrangement. Pair frequency did not increase with limpet density suggesting pairing was not an incidental consequence of crowding. Pair living was unknown in the genus Siphonaria, and is very uncommon among simultaneous hermaphrodites. Reproductive synchrony and restrictions on movement due to predation and environmental stress may limit opportunities for encountering and mating with multiple partners favoring pair living in S. gigas.     

High soil and groundwater arsenic levels induce high body arsenic loads,health risk and potential anemia for inhabitants of northeastern Iran

Arsenic bioavailability in rock, soil and water resources is notoriously hazardous. Geogenic arsenic enters the body and adversely affects many biochemical processes in animals and humans, posing risk to public health. Chelpu is located in NE Iran, where realgar, orpiment and pyrite mineralization is the source of arsenic in the macroenvironment. Using cluster random sampling strategy eight rocks, 23 soils, 12 drinking water resources, 36 human urine and hair samples and 15 adult sheep urine and wool samples in several large-scale herds in the area were randomly taken for quantification of arsenic in rock/soil/water, wool/hair/urine. Arsenic levels in rock/soil/water and wool/hair/urine were measured using inductively coupled plasma spectroscopy and atomic absorption spectrophotometry, respectively. While arsenic levels in rocks, soils and water resources hazardously ranged 9.40–25,873.3 mg kg^?1, 7.10–1448.80 mg kg^?1 and 12–606 μg L^?1, respectively, arsenic concentrations in humans’ hair and urine and sheep’s wool and urine varied from 0.37–1.37 μg g^?1 and 9–271.4 μg L^?1 and 0.3–3.11 μg g^?1 and 29.1–1015 μg L^?1, respectively. Local sheep and human were widely sick and slightly anemic. Hematological examination of the inhabitants revealed that geogenic arsenic could harm blood cells, potentially resulting in many other hematoimmunological disorders including cancer. The findings warn widespread exposure of animals and human in this agroecologically and geopolitically important region (i.e., its proximity with Afghanistan, Pakistan and Turkmenistan) and give a clue on how arsenic could induce infectious and non-infectious diseases in highly exposed human/animals.