Muscle dimensions in the Japanese macaque hand

Macaques have been used as an important paradigm for understanding the neural control mechanisms of human precision grip capabilities. Therefore, we dissected the forearms and hands of two male Japanese macaques to systematically record the muscle mass, fascicle length and physiological cross-sectional area (PCSA). Comparisons of the mass fractions and PCSA fractions of the hand musculature among the Japanese macaque, chimpanzee, and human demonstrated that the sizes of the thenar and hypothenar eminence muscle groups are more balanced in the macaque and chimpanzee, but those of the thenar eminence group are much larger in the human, indicating that the capacity to generate force at the tip of the thumb is more restricted in macaques, despite their high manual dexterity. In the macaque, however, the extrinsic flexor muscles are much larger, possibly to facilitate weight bearing by the forelimbs in pronograde quadrupedal locomotion and forceful grasping of arboreal supports in gap-crossing movements such as leaping. Taking such anatomical differences imposed on the hand musculoskeletal system into consideration seems to be an important method of clarifying the mechanisms of precision grip in macaques.     

Congenital malformations in Japanese macaques (Macaca fuscata) at Takasakiyama

From the late 1960s to the early 1970s, many congenitally malformed infants were born into provisioned Japanese macaque troops. Although the exact cause of this problem was not determined, the occurrence of malformations decreased thereafter. We examined possible factors such as total population size, number of adult females, birth rate, and volume of provisioned food. Agrichemicals attached to provisioned food are suspected as the main cause, as other factors were found to have no influence. Many more malformations were seen in males compared with females, in feet compared with hands, and in the fourth compared with other digits. We confirmed that the frequency of congenital malformation was high during the 1960s through to the mid-1970s when increased levels of provisioned food were given and that the incidence of congenital malformations was also elevated among wild macaques during this time.     

Sifaka positional behavior: ontogenetic and quantitative genetic approaches

In many primate species, hands and feet are large relative to neonatal body weight, and they subsequently exhibit negative allometric growth during ontogeny. Here, data are presented showing that this pattern holds for a wild population of lemur, Verreaux's sifaka (Propithecus verreauxi verreauxi). Using morphometric data collected on this population, it is shown that younger animals possess relatively large hands and feet. This ontogenetic pattern suggests a simple behavioral test: do juvenile animals with their larger, almost adult‐sized hands and feet locomote on similarly sized substrates as adult animals? Using locomotor bout sampling, this question was tested by collecting positional behavior data on this population. Results from this test find no differences in locomotor behaviors or substrate use between yearlings and adult animals. To place these results in a broader evolutionary context, heritabilities and selection gradients of hands, feet, and other limb elements for animals in this population were estimated. Among limb elements, heritabilities range from 0.16–0.44, with the foot having the lowest value. Positive directional selection acts most strongly on the foot (directional selection gradient = 0.119). The low heritability and positive selection coefficient indicate that selection has acted, and continues to act, on foot size in young animals. These results are interpreted within a functional context with respect to the development of locomotor coordination: larger feet enable young animals to use “adult‐sized” substrates when they move through their habitat. It is suggested that the widespread pattern of negative allometry of the extremities in sifaka and other primates is maintained by selection, and does not simply reflect a primitive developmental pathway that has no adaptive basis. Am J Phys Anthropol 131:261–271, 2006. © 2006 Wiley‐Liss, Inc.     

Energy budget of the chicken foot

1. 1.|A mathematical model predicts the energy loss from a chicken foot provided the following variables are known: body temperature, air temperature, wind velocity, blood flow to the foot, and the relative partitioning of blood flow via two distinct venous returns.

2. 2.|Chickens are capable of keeping their feet from freezing at temperatures as low as −30°C ambient, but at a high energy cost.

3. 3.|Chickens can modulate blood flow to their feet at thermoneutral temperatures enough to vary heat loss to environment by about one-fourth metabolic heat production.

Status of urban populations of the long-tailed macaque (<Emphasis Type="Italic">Macaca fascicularis</Emphasis>) in West Sumatra,Indonesia

We studied long-tailed macaque (Macaca fascicularis) populations in Padang, West Sumatra, Indonesia, focusing on the effect of human provisioning on their demography and dietary composition. We conducted a field survey at three sites in the city: Gunung Meru, Gunung Padang, and Gunung Panggilun. Mean troop size (range 28–68) and infant ratio (range 0.38–1.00) were greater in Gunung Meru, where the macaques have been highly provisioned, than at the other two study sites (troop size 10–15; infant ratio 0.00–0.33). The macaques at all sites consumed both natural and human foods, but dependence on the latter differed among sites: three-quarters of the diet of macaques in Gunung Meru consisted of human foods, while human foods comprised less than 5% of the macaque diet at the other sites. The ability of macaques to modify the proportion of human food is a behavioral flexibility that facilitates the survival of the long-tailed macaque in urban habitats. Without restrictions on provisioning, the degree of dependence of macaques on human foods and population size could increase, especially in Gunung Meru, and human–macaque conflict could escalate. In order to create an effective management policy for urbanized monkeys, long-term quantitative data on macaque behavior and monitoring of population parameters are required.     

Human–wildlife conflict: Proximate predictors of aggression between humans and rhesus macaques in India

Macaques live in close contact with humans across South and Southeast Asia, and direct interaction is frequent. Aggressive contact is a concern in many locations, particularly among populations of rhesus and longtail macaques that co‐inhabit urbanized cities and towns with humans. We investigated the proximate factors influencing the occurrence of macaque aggression toward humans as well as human aggression toward macaques to determine the extent to which human behavior elicits macaque aggression and vice versa. We conducted a 3‐month study of four free‐ranging populations of rhesus macaques in Dehradun, India from October–December 2012, using event sampling to record all instances of human‐macaque interaction (N = 3120). Our results show that while human aggression was predicted by the potential for economic losses or damage, macaque aggression was influenced by aggressive or intimidating behavior by humans as well as recent rates of conspecific aggression. Further, adult female macaques participated in aggression more frequently than expected, whereas adult and subadult males participated as frequently as expected. Our analyses demonstrate that neither human nor macaque aggression is unprovoked. Rather, both humans and macaques are responding to one another's behavior. Mitigation of human‐primate conflict, and indeed other types of human‐wildlife conflict in such coupled systems, will require a holistic investigation of the ways in which each participant is responding to, and consequently altering, the behavior of the other. Am J Phys Anthropol 156:286–294, 2015. © 2014 Wiley Periodicals, Inc.     

Patient-specific modelling of the foot: automated hexahedral meshing of the bones

Subject-specific finite element modelling is a powerful tool for carrying out controlled investigations of the effects of geometric and material property differences on performance and injury risk. Unfortunately, the creation of suitable meshes for these models is a challenging and time-intensive task. This paper presents an automated method of generating fully hexahedral meshes of the bones of the feet which requires only surface representations as inputs. The method is outlined and example meshes, using two human feet and the foot of a Japanese macaque, are given to demonstrate its flexibility. Mesh quality is also evaluated for the calcaneus, first metatarsal, navicular and talus. Streamlining the generation of finite element meshes of the foot will ease investigations into the patient-specific biomechanics of injury.     

An investigation of ecological correlates with hand and foot morphology in callitrichid primates

Studies of primate taxonomy and phylogeny often depend on comparisons of limb dimensions, yet there is little information on how morphology correlates and contributes to foraging strategies and ecology. Callitrichid primates are ideal for comparative studies as they exhibit a range of body size, limb proportions and diet. Many callitrichid species exhibit a high degree of exudativory, and to efficiently exploit these resources, they are assumed to have evolved morphologies that reflect a level of dependence on these resources. We tested assumptions by considering measurements of limb proportion and frictional features of the volar surfaces in preserved specimens of 25 species with relation to published life history and ecological data. The degree of exudativory and utilization of vertical substrates during foraging were found to correlate both with size and with size‐corrected foot and hand dimensions. Smaller species, which engage in greater degrees of exudativory, had proportionally longer hands and feet and more curved claw‐like tegulae (nails) on their digits to facilitate climbing on vertical substrates. The density of patterned ridges (dermatoglyphs) on the volar surfaces of the hands and feet is higher in more exudativorous genera, suggesting a role in climbing on vertical tree trunks during foraging. Dermatoglyph comparisons suggest that ridges on the soles and palms may facilitate food procurement by enhancing frictional grip during exudate feeding. Volar pad features corroborate taxonomic relationships described from dental morphology. Am J Phys Anthropol 152:447–458, 2013. © 2013 Wiley Periodicals, Inc.     

Is Diet Flexibility an Adaptive Life Trait for Relictual and Peri-Urban Populations of the Endangered Primate Macaca sylvanus?

Habitat loss, fragmentation and urban expansion may drive some species to marginal habitats while others succeed in exploiting urban areas. Species that show dietary flexibility are more able to take advantage of human activities to supplement their diet with anthropogenically abundant and accessible resources. The Barbary macaque (Macaca sylvanus) is an endangered species due to the loss of its habitat, and human pressure. The population of Gouraya National Park (Algeria) lives in a relictual habitat that constitutes about 0.6% of the species range. In addition, this population is a unique case where urban expansion favours contact zones between Barbary macaque habitats and a big city (Bejaia). We quantified the dietary composition of Gouraya macaques over an annual cycle with the objective to understand how diet flexibility of this species may help it adapt to a relictual habitat or cope with urban expansion. We recorded the phenology of plant species every month. This study shows that Gouraya macaques, compared to those living in other forest types of the distribution area, are under lower seasonal constraints. They consume a greater amount of fruit and seeds that are available throughout much of the year, and a lesser amount of costly to find and extract subterranean foods. Therefore the Gouraya relictual habitat appears as a favourable environment compared to other major habitats of that species. This study also shows that colonizing peri-urban zones increases the availability and species richness of diet resources for Barbary macaques as they consume more human foods and exotic plants than in farther sites. Adult males eat more human foods than adult females and immatures do. The exploitation of high-energy anthropogenic food could favour macaque population growth and expansion towards the city center associated with human/macaque conflicts. We recommend applying management actions to restore macaques back to their natural habitat.     

They Wallop Like They Gallop: Audiovisual Analysis Reveals the Influence of Gait on Buttress Drumming by Wild Chimpanzees (Pan troglodytes)

The role learning plays in the acquisition of communicative gestures by wild chimpanzees (Pan troglodytes) is unclear. We aimed to evaluate the likelihood that social experience influences the structure of chimpanzee buttress drumming displays by examining whether individuals differed in the way they used their hands and feet to strike trees. We analyzed digital video recordings of 245 bouts by 9 adult males from Gombe National Park, Tanzania, frame by frame in conjunction with acoustic analysis. We investigated 1) how limb sequences used to approach drumming trees influenced limb use during drumming, 2) the relative use of hands vs. feet in drumming, and 3) the relative amplitude of beats produced by hands vs. feet. We found that the chimpanzees most often approached trees at a gallop and usually initiated drumming bouts with limb sequences that were identical to gait limb sequences. All individuals produced more beats with their feet than with their hands, and foot beats were higher in relative amplitude than hand beats. In only one instance did an individual produce a bout with hands only, whereas in three of nine observations of drumming on resonant camp equipment, the individuals primarily used their hands rather than their feet. We suggest that although chimpanzees may, by observing others, learn to use buttresses as tools to generate loud sounds, it is unlikely that learning influences the structure of displays because they result from innately determined gait patterns deployed to generate sound from comparatively nonresonant substrates.     

Comparative analysis of macaque and human sperm proteomes: Insights into sperm competition

Male macaques produce faster sperm than male humans due to a higher pressure of sperm competition in macaques. To explore the molecular basis of this biological difference, we firstly constructed macaque and human sperm proteomes using LC?MS/MS. We then detected the positively selected genes specifically on the branch of macaque based on branch‐site likelihood method. We identified 197 positively selected genes specifically on the branch of macaque that are unselected in corresponding human orthologs. These genes are highly associated with mitochondria and axoneme that directly drive sperm motility. We further compared the ultrastructural differences of the midpiece between macaque and human sperms to provide evidence for our findings using transmission electron microscopy. In conclusion, our results provide potential molecular targets for explaining the different phenotypes under sperm competition between macaques and humans, and also provide resources for the analysis of male fertility.     

Integration and Evolvability in Primate Hands and Feet

Morphological integration theory predicts that sets of phenotypic traits that covary strongly due to developmental and/or functional connections between them eventually co-evolve because of a coordinated response to selection, and accordingly become less independently evolvable. This process is not irreversible, however, and phenotypic traits can become less integrated, and hence more independently evolvable, in the context of selection for divergent functions and morphologies. This study examines the reciprocal relationship between shared function, integration and evolvability by comparing integration patterns among serially homologous skeletal elements in the hands and feet of a functionally diverse sample of catarrhine primates. Two hypotheses are tested: (1) species in which the autopods are functionally more similar (e.g. quadrupedal monkeys) have more strongly integrated autopods than species in which the autopods are functionally divergent (e.g. gibbons, humans) and (2) the latter have autopods that are more evolvable, collectively and independently. Morphometric data from selected hand and foot digital rays were used to derive phenotypic variance/covariance matrices. The strength of integration among autopods was quantified using eigenanalysis and a measure of trait variational autonomy. Evolvability was estimated by subjecting phenotypic variance/covariance matrices to simulated random selection gradients, and comparing evolutionary responses among species. Results indicate that integration decreases as hands and feet become functionally divergent, and that the strongly integrated hand and foot skeletons of quadrupedal monkeys respond to selection in a highly collinear manner, even when simulated selective pressures acting on each autopod are in opposite directions in phenotypic space. Results confirm that the evolvability of morphological traits depends largely on how strongly they covary with other traits, but also with body size. The role of pleiotropy as a developmental mechanism underlying integration and evolvability is also discussed.     

Symmetrical gaits of primates

Walking and symmetrical running gaits of 26 genera of primates are analyzed using numerical and graphical methods described previously. The raw data are 1701 feet of 16 mm motion picture film mostly exposed at 64 frames per second. Adult monkeys and apes usually use the walking trot or diagonal-sequence walks. Individual monkeys occasionally use lateral-sequence walks resembling those that are usual for human infants. Human children moving on hands and feet use gaits ranging from the walking pace through the lateral-sequence walks to the walking trot. An infant macaque studied from age 17 hours to 96 days first walked with a lateral-sequence, diagonal-couplets gait and then gradually shifted to the diagonal-sequence, diagonal-couplets gait of the adult. Few non-primates use the diagonal-sequence walks which are typical of primates. Typical support sequences are figured. Relative placement of feet and consequent slight asymmetry are described.     

Body Site Variation of Cool Perception Thresholds,with Observations on Paradoxical Heat

Thresholds for the perception of coolness and heat pain were determined in sessions that randomly intermixed temperature increases and decreases. Four body sites were tested bilaterally: thenar eminence of the hand, plantar surface of the foot, dorsolateral forearm, and lateral calf. Coolness thresholds were lowest for the hand, intermediate for the forearm, and highest for the leg and foot. Laterality differences were not statistically significant.

In 34% of the sessions, subjects did not consistently report cool or cold sensations with detectable temperatue decreases. When they did not report cool or cold, they most often reported heat or pain, thus exhibiting the phenomenon of “paradoxical heat”. There were significantly more paradoxical heat responses when cooling stimuli were intermixed with painfully hot stimuli than when they were intermixed with only warm stimuli.

There was no significant correlation observed between thresholds for coolness and heat pain, either across body sites or across subjects at any single body site. This result implies that the various factors relevant to thermal sensitivity (i.e., thermal properties of the epidermis, innervation density) are differentially important for cool versus heat pain perception.     

The hands and feet of Archaeolemur: metrical affinities and their functional significance

Recent expeditions to Madagascar have recovered abundant skeletal remains of Archaeolemur, one of the so-called "monkey lemurs" known from Holocene deposits scattered across the island. These new skeletons are sufficiently complete to permit reassembly of entire hands and feet--postcranial elements crucial to drawing inferences about substrate preferences and positional behavior. Univariate and multivariate analysis of intrinsic hand and foot proportions, phalangeal indices, relative pollex and hallux lengths, phalangeal curvature, and distal phalangeal shape reveal a highly derived and unique morphology for an extinct strepsirrhine that diverges dramatically from that of living lemurs and converges in some respects on that of Old World monkeys (e.g., mandrills, but not baboons or geladas). The hands and feet of Archaeolemur are relatively short (extremely so relative to body size); the carpus and tarsus are both "long" relative to total hand and foot lengths, respectively; phalangeal indices of both the hands and feet are low; both pollex and hallux are reduced; the apical tufts of the distal phalanges are very broad; and the proximal phalanges are slightly curved (but more so than in baboons). Overall grasping capabilities may have been compromised to some extent, and dexterous handling of small objects seems improbable. Deliberate and noncursorial quadrupedalism was most likely practiced on both the ground and in the trees. A flexible locomotor repertoire in conjunction with a eurytopic trophic adaptation allowed Archaeolemur to inhabit much of Madagascar and may explain why it was one of the latest surviving subfossil lemurs.     

The extensor assembly in two species of opossum,Philander opossum and Didelphis marsupialis

In considering primate and hominoid phylogeny, the fundamental position assigned to opossums is explained partially by the characteristic morphology of their hands and feet. One of the main functional features of the human hand is the ability to make a stabilized arch of the finger. Because the extensor assembly plays a key role in establishing an arched finger, the extensor systems of the digits of both the hands and feet were studied in two species of opossum, Philander opossum and Didelphis marsupialis. In the foot, two extensor tendons join in each toe to form one tendinous plate, which inserts onto the base of the second phalanx. Lumbricals join this plate along the tibial side, and interosseus insertions are found, although a true interosseus wing is lacking. At the proximal interphalangeal level, a terminal tendon takes its origin from this tendinous plate. This terminal tendon is oval in cross-section and contains elastic structures. Oblique bands arise from this terminal tendon and run proximally along the proximal interphalangeal joint inserting onto the base of the first phalanx. There are elastic structures in the flexor tendon on the dorsal side near its site of insertion. In the hand, the main extensor tendons are arranged differently and the interossei contribute substantially to the extensor assembly. Otherwise, the extensor assembly of the hands and feet are quite similar. The function of the so-called paratendinous intravaginal flexors is discussed as are evolutionary aspects of the extensor assembly.     

Local cold exposure of Andean Indians during normal and simulated activities.

Thermal resonses of Andean Indians were measured during several customary tasks associated with cold exposure in the highlands of southern Peru. These included surface temperature measurements of women while they washed clothing in the river and similar measurements of men while they constructed a diversion channel in the same river. A third test measured the effects of alcohol consumption on body temperatures during light activity. Women maintained slightly warmer hand than foot temperatures. Men maintained nearly equal hand and foot temperatures during the exposure period. Among male subjects the foot rewarmed at a faster rate than the hand. The results from the field studies compared favorably with results from earlier laboratory exposure tests. Comparisons between the river water exposure tests for males and females showed a consistent pattern where females maintained warmer hand and foot temperatures than males. These findings were in accord with previous laboratory studies among Quechua Indians and with the findings reported for other ethnic groups who experience natural cold stress. Alcohol ingestion appeared to have minimal effect in mitigating cold stress response during light activity. This finding was counter to earlier laboratory tests of resting subjects.     

Macaque–human interactions and the societal perceptions of macaques in Singapore

Humans and long‐tailed macaques (Macaca fascicularis) interface in several locations in Singapore. We investigated six of these interface zones to assess the level of conflict between the two species. We observed macaque‐to‐human interactions and distributed questionnaires to residents and visitors of nature reserves. We observed an average of two macaque‐to‐human interactions per hour at the sites, which included affiliative or submissive behaviors (46.9%), aggression (19.1%), taking food and other items (18.5%) searching bins, cars, and houses (13.4%), and nonaggressive contact (2.1%). Two‐thirds of interactions occurred when a human was carrying food or food cues, and one‐quarter occurred when a human provoked macaques. Only 8% of interactions occurred without a clear human‐triggered context. Our interview showed one‐third of respondents experienced nuisance problems from macaques. They had items taken from them (50.5%) and received threats (31.9%). Residents reported more nuisance problems than visitors, and their perceptions toward macaques differed. Residents were more aware of the consequences of food provisioning and that there were regulations against feeding. Residents fed macaques less and held more negative sentiments toward macaques. Nearly half of the interviewed people held neutral attitudes toward macaques and only 26.2% of respondents thought conflict with macaques warranted urgent action. Nearly two‐thirds of the respondents supported education programs to ameliorate human–macaque conflict, and less than 15% supported removing or eradicating macaques. 87.6% felt that it is importance to conserve and protect macaques. Our results show that human–macaque conflict exists in Singapore, but that it may not be severe. Human behavior is largely responsible for macaque‐to‐human interactions, and thus could be lessened with management of human behavior in interface zones (i.e. restrict food carrying and provocation). Moreover, our interviews shows people living in Singapore value macaques, do not wish them entirely removed, prefer education‐based solutions, and consider conservation and protection of them important. Am. J. Primatol. 71:825–839, 2009. © 2009 Wiley‐Liss, Inc.     

Thermal biofeedback and periodic movements in sleep: Patients' subjective reports and a case study

Periodic movements in sleep (PMS) is a sleep disorder characterized by repetitive leg kicks accompanied by arousals. In our clinical experience, many patients with PMS anecdotally report that they suffer from cold feet. This study explored whether there is an increased incidence of cold feet complaints in patients with periodic movements in sleep. Results indicated that, indeed, significantly more patients with leg kicks complain of cold feet as compared to patients without leg kicks. A case study was then conducted to determine whether foot thermal biofeedback training would alleviate symptoms of periodic movements in sleep. The number of leg kicks decreased from a mean of 536 per night before biofeedback training to a mean of 19.5 after training. These data lend support to our hypothesis that poor circulation may be contributing to the severity of periodic movements in sleep and that thermal biofeedback may afford an alternative treatment strategy.