Kevin D. Hunt

Bio: Kevin D. Hunt is an academic researcher from Indiana University. The author has contributed to research in topics: Animal ecology & Population. The author has an hindex of 25, co-authored 68 publications receiving 3860 citations. Previous affiliations of Kevin D. Hunt include Harvard University & Stone Age Institute.

Dietary Response of Chimpanzees and Cercopithecines to Seasonal Variation in Fruit Abundance. II. Macronutrients

Abstract: In a continuation of our study of dietary differentiation among frugivorous primates with simple stomachs, we present the first comparison of differences in dietary macronutrient content between chimpanzees and cercopithecine monkeys Previously we have shown that chimpanzee and monkey diets differ markedly in plant part and species content We now examine whether this diet diversity is reflected in markedly different dietary macronutrient levels or the different feeding strategies yield the same macronutrient levels in their diets For each primate group we calculated the total weighted mean dietary content of 4 macronutrients: crude lipid (lipid), crude protein (CP), water-soluble carbohydrates (WSC), and total nonstructural carbohydrates (TNC) We also calculated 4 fiber fractions: neutral-detergent fiber (NDF), which includes the subfractions hemicellulose (HC), cellulose (Cs), and sulfuric acid lignin (Ls) The HC and Cs are potentially fermentable fibers and would contribute to the energy provided by plant food, depending on the hind gut fermenting capacity of the individual primate species The chimpanzee diet contained higher levels of WSC and TNC because during times of fruit abundance the chimpanzees took special advantage of ripe fruit, while the monkeys did not The monkey diets contained higher levels of CP because the monkeys consumed a constant amount of leaf throughout the year All four primate species consumed diets with similar NDF levels However, the chimpanzees also took advantage of periods of ripe fruit abundance to decrease their Ls levels and to increase their HC levels Conversely, the monkey diets maintained constant levels of the different fiber fractions thoughout the year Nevertheless, despite these differences, the diets of the 4 frugivores were surprisingly similar, considering the substantial differences in body size We conclude that the chimpanzee diet is of higher quality, particularly of lower fiber content, than expected on the basis of their body size

Estimators of Fruit Abundance of Tropical Trees1

Abstract: Many types of biological studies require the estimation of food abundance in tropical forests, and a variety of methods have been used to estimate this parameter. Here we compare the accuracy and precision of three methods for estimating the fruit abundance (biomass and number) of tropical tree species: tree diameter, crown volume, and visual estimation. Diameter at breast height (DBH) was the most consistently accurate method and exhibited low levels of interobserver variability. Generally, crown volume was neither precise nor accurate. The visual estimation method was accurate for trees with very large fruit, but exhibited high interobserver variability.

Standardized descriptions of primate locomotor and postural modes

Abstract: As quantitative studies on primate positional behavior accumulate the lack of a standard positional mode terminology is becoming an increasingly serious deficiency. Inconsistent use of traditional terms and inappropriate conflation of mode categories hamper interspecific and interobserver comparisons. Some workers use common terms without definition, allowing at least the possibility of misunderstanding. Other researchers coin neologisms tailored to their study species and not clearly enough defined to allow application to other species. Such neologisms may overlap, may completely encompass, or may conflate previously defined labels. The result is, at best, the proliferation of synonyms and, at worst, the creation of confusion where clarity had existed. Historical precedents have sometimes resulted in “catch-all” terms that conflate any number of kinematically different behaviors (e.g. “brachiation,” “climbing,” and “quadrumanous climbing”). We recognize three areas where distinction of positional modes has some current importance: (1) Modes that require humeral abduction should be distinguished from adducted behaviors; (2) locomotor modes that involve ascent or descent should be distinguished from horizontal locomotor modes; and (3) suspensory modes should be distinguished from supported modes. We recommend a nomenclature that is not dedicated to or derived from any one taxonomic subset of the primates. Here we define 32 primate positional modes, divided more finely into 52 postural sub-modes and 74 locomotor sub-modes.

Demography, female life history, and reproductive profiles among the chimpanzees of Mahale

Abstract: Demography provides critical data to increase our understanding of the evolution, ecology, and conservation of primate populations. The chimpanzees of the Mahale Mountains National Park, Tanzania, have been studied for more than 34 yr on the basis of individual identification and standardized attendance records. From this long-term study, we derived the following demographic data: The major cause of death was disease (48%), followed by senescence (24%) and within-species aggression (16%). Fifty percent of Mahale chimpanzees died before weaning. The median ages of female life history variables were: first maximal swelling, 10.0 yr (n = 5); emigration, 11.0 yr (n = 11); and first birth, 13.1 yr (n = 5). The median period of adolescent infertility was 2.8 yr (n = 4) when calculated from the age at immigration to that at first birth. Female fecundity was highest between 20 and 35 yr of age, with an annual birth rate of 0.2. Twenty-six females that were observed from a young age (10-13 yr) to death at various ages (15-40 yr) gave birth to an average of 3.9 and weaned an average of 1.4 offspring. Twenty-five females that were observed from middle age (18-33 yr) to death in older age (31-48) gave birth to an average of 2.7 and weaned an average of 2.0 offspring. The post-reproductive lifespan for female chimpanzees was defined as the number of years that passed from the year when the last offspring was born to the year when the female died, minus 5. Twenty-five percent of old females had a post-reproductive lifespan. The interbirth interval after the birth of a son (x = 72 mo) tended to be longer than that after the birth of a daughter (x = 66 mo). The extent of female transfer, which is a rule in chimpanzees, is influenced by the size and composition of the unit group and size of the overall local community.

Positional behavior of Pan troglodytes in the Mahale Mountains and Gombe Stream National Parks, Tanzania.

Abstract: The positional behavior of habituated adult chimpanzees and baboons was observed for 784 hr in a year-long study. Comparisons between species were made to establish the distinctiveness of chimpanzee positional behavior and habitat use. Brachiation (sensu stricto, i.e., hand-over-hand suspensory locomotion) was observed in low frequencies among chimpanzees, and its significance for chimpanzee anatomy is judged slight. Although no significant differences were found between sympatric baboons and chimpan- zees in the proportion of time spent in the terminal branches, or in the mean diameter of weight-bearing strata, chimpanzees exhibited evidence of a termi- nal branch adaptation in that they, unlike baboons, used postures among smaller supporting strata different from those used among larger supports. Among chimpanzees, unimanual arm-hanging was most common among the smallest strata and was associated with smaller mean and median support diameter than other postures. Unimanual arm-hanging was the only common behavior among chimpanzees that usually involved complete abduction of the humerus. A number of behaviors often subsumed under the label "quadruman- ous climbing" were distinguished in this study. Compared to baboons and other cercopithecoids, chimpanzees did not show increased frequencies of large-stratum vertical climbing, and their vertical climbing did not involve significant humeral abduction. Arm-hanging (i.e., unimanual suspension) and vertical climbing distinguish chimpanzee positional behavior from that of monkeys.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

Abstract: The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

The Expensive-Tissue Hypothesis: The Brain and the Digestive System in Human and Primate Evolution

Abstract: Les tissus du cerveau sont une extension metabollique, mais il n'existe pas de correlation significative entre le taux metabolique relatif de base et la taille relative du taille chez les humains et autres mammiferes a encephale. L'apport en graisses animales dans la nourriture est essentiel dans l'evolution du cerveau humain

A new species

Abstract: We redescribe the only previously known species of Myrsidea from bulbuls, M. pycnonoti Eichler. Sixteen new species are described; they and their type hosts are: M. phillipsi ex Pycnonotus goiavier goiavier (Scopoli), M. gieferi ex P. goiavier suluensis Mearns, M. kulpai ex P. flavescens Blyth, M. finlaysoni ex P. finlaysoni Strickland, M. kathleenae ex P. cafer (L.), M. warwicki ex Ixos philippinus (J. R. Forster), M. mcclurei ex Microscelis amaurotis (Temminck), M. zeylanici ex P. zeylanicus (Gmelin), M. plumosi ex P. plumosus Blyth, M. eutiloti ex P. eutilotus (Jardine and Selby), M. adamsae ex P. urostictus (Salvadori), M. ochracei ex Criniger ochraceus F. Moore, M. borbonici ex Hypsipetes borbonicus (J. R. Forster), M. johnsoni ex P. atriceps (Temminck), M. palmai ex C. ochraceus, and M. claytoni ex P. eutilotus. A key is provided for the identification of these 17 species.

A theory of human life history evolution: Diet, intelligence, and longevity

Abstract: Human life histories as compared to those of other primates and mammals have at least four distinctive characteristics: an exceptionally long life span an extended period of juvenile dependence support of reproduction by older post-reproductive individuals and male support of reproduction through the provisioning of females and their offspring. Another distinctive feature of our species is a large brain with its associated psychological attributes: increased capacities for learning cognition and insight. In this paper the authors propose a theory that unites and organizes these observations and generates many theoretical and empirical predictions. The authors present some tests of those predictions and outline new predictions that can be tested in future research by comparative biologists archaeologists paleontologists biological anthropologists demographers geneticists and cultural anthropologists. (authors)