Survey and census of howler monkeys (Alouatta palliata) in the rain forest of “Los Tuxtlas,” Veracruz,Mexico

Howler monkey troops were censused at the biological reserve “Los Tuxtlas” in Veracruz, Mexico. The reserve includes 700 ha of rain forest. Twenty howler monkeys were also trapped, measured, marked, and released. Censuses were conducted for a period of 26 months, and they indicated the existence of 17 troops. The mean troop size was 9.12 (SD ± 2.93), and mean troop composition was 3.0 adult males, 4.12 females, 1.56 juveniles, and 1.54 infants. Ecological density was 0.23 howlers/ha or 23.29 howlers/km². The male to female ratio was 1:1.37. No discrete seasonality in births was noted. Howler monkeys in this locality inhabit the northernmost limit of the neotropical rain forest. The population parameters fall within those reported for Alouatta palliata at other sites.     

Troop Histories and Range Inertia of Lemur catta at Berenty,Madagascar: A 33-year Perspective

Lemur catta troops in a 1-km ² study area at Berenty Reserve have maintained fidelity to core areas since Budnitz and Dainis' study of 1972–1973, and for two troops possibly since 1963. Population in 1 km ² fluctuated from 155 to 105 to 282 individuals (excluding infants), and the number of troops increased from 12 to 21. Most troops retain the same core areas from year to year (170 observed troop-years). Ten troops derived from known fissions have settled in parts of their parent troop range or an adjacent neighbor's range. Five more troops may derive from similar matrilocal fissioning, inferred from behavior and ranging patterns. One has remained unchanged. Five have unknown parentage, in the ranges of four previously censused troops. Once a fissioned troop completely replaced another, one troop permanently extended its range, three times females joined a different troop, once a female remained nomadic for two years without stable home range. No fissioned troop has been seen to leapfrog others: to settle discontiuously from its parent. Intertroop antagonism may reflect benefits of long-term core area control.     

On the dynamics of the hanuman langur populations of jodhpur (Rajasthan,India)

The city of Jodhpur (26°18′N, 73°8′E) supports a population of about 900 hanuman langurs (Presbytis entellus) divided into 24 bisexual troops and 12 all-male bands in an area of 60 km². This population has been censused from 1968 to 1978. Over this period the population of bisexual troops has remained stable around 700, while the population of all-male bands has increased from 160 to 230 individuals. The bisexual troops show a tendency towards a reduction in population growth rate with increasing troop size, with troops over 50–60 tending to split. Very small troops may grow by large scale immigration. Although a number of male changes and mortality through infanticide have been recorded, there is no evidence of a regular periodicity in the occurrence of initial, growth and mature phases in the life history of a bisexual troop. Unlike the bisexual troops, the all-male bands show no tendency towards a reduction in growth rate with the increase in band size, but show a continuous growth of band size over the study period. Langurs of Jodhpur rely heavily on cultivated fields for their sustenance. This cultivation has been on increase over the study period, and since the males invade cultivation more readily, they may have been able to take fuller advantage of these increasing resources and affect a population increase that has not been possible for the bisexual troops.     

Preliminary observations on the ecology and behavior of the Capped Langur,Presbytis pileatus,in the Madhupur forest of Bangladesh

Between the rainy season months of July and November 1976, the author censused and intensively studied for 50 hr the capped langur,Presbytis pileatus, in the Madhupur Forest, Bangladesh. Transects were made in the forest to provide tree girth and height measurements. The predominant tree species is sal,Shorea robusta. The mean group size for capped langur troops observed in excess of 1 hr was 8.7, and that for troops censused for less than 1 hr, 7.5. Troops were primarily unimale, but one all-male band of four and a solitary adult male were sighted. The adult sex ratio of females to males was 2:1. The equivalent ecological density for intensively studied troops was 92 individuals/km². Estimated ecological biomass was equal to 716.5 kg/km². A daily activity profile shows that the capped langur has a bimodal feeding schedule. Midday is clearly a rest period. Adult males spend much time in sentinel behavior and an unusual penile display is described. Instances of intergroup antagonism are detailed. Fighting was observed on one occasion. Vocalizations are described by context of emission.     

The numbers and distribution of elephant Loxodonta africana in the Rwenzori National Park and Chambura Game Reserve, Uganda

A series of aerial counts of elephant made between 1968 and 1972 in the Rwenzori National Park and Chambura Game Reserve, Uganda, is described. A summary is included of all previous aerial counts made in the region. Numbers present in the park since 1963 averaged 1752 during the dry seasons, some 3/5 of the wet season mean of 2896. Corresponding figures for the reserve are 325 and 501. The distribution was very significantly aggregated for each count and remained so when the totals for all counts were lumped. The distribution tended to be more aggregated in dry than in wet seasons. The overall density in the park was 1.43 elephant km-² with wet and dry season means of 1.74 and 1.05 respectively. Corresponding figures for the reserve are 2.06, 2.42 and 1.57 km-². The mean group size in the park was 6.3 elephant but there were significant variations over the whole range of observations although not between wet and dry season means. The elephant in the reserve were highly aggregated with a mean group size of 28.8. It is concluded that there was a significant rise in the wet season population of the park between 1963 and 1968 but that subsequently, numbers remained fairly stable. Numbers in the dry season and in the reserve at all seasons have not varied significantly since 1963. It is suggested that the wet season rise has been due to a reduction in the area of grazing land available outside the park at this time of year. It is concluded that vegetational differences are responsible for the un even distribution of elephant with human disturbance having an effect in some areas. It is believed that in the region censused, there are at least three distinct populations of elephant of which only that in the reserve is showing signs of stress.     

Causes of Intraspecific Aggression in Alouatta palliata mexicana: Evidence from Injuries,Demography, and Habitat

Although howlers have been traditionally considered to be pacific, showing one of the lowest rates of aggression among primates, new evidence is emerging to question this image. We present data on injuries in Mexican mantled howlers (Alouatta palliata mexicana) in relation to different sociecological parameters. We censused howler populations in 19 forest fragments over a 17-mo period in the Los Tuxtlas Region, southern Veracruz, Mexico. We conducted detailed observations of scars, torn lips, broken fingers, mutilated tails and other visible injuries. We also collected data on the demography, biogeography and vegetation of each fragment in order to relate injury data to them. We censused 333 howlers, of which we exhaustively observed 254 for injuries. Four resident adult females (n = 108) and 29 adult resident males (n = 76) had injuries, while none of the solitary males (n=16), solitary females (n=1), juveniles (n=23) and infants (n=30) had them. We discuss possible interpretative scenarios for the distribution of injuries. Although some results suggest that food resource concentration may determine intergroup agonistic encounters, we propose that physical injury is primarily associated with male-male agonistic encounters during takeovers, and consequently it could indicate migration among troops.     

Demography of Lemur catta at Berenty Reserve,Madagascar: Effects of Troop Size,Habitat and Rainfall

We censused Lemur catta within a 1 km² study area at Berenty Reserve, Madagascar, during the September–October birth season for 19 years between 1963 and 2000, a total of 290 troop counts (266 with age and sex). The non-infant population was 155 in 1972–5, fell to 105 in 1985, and rose to a maximum of 282 in 1997, while troops increased from 12 in 1972–1985 up to 25 in 1998–2000. Local density varies between habitat types from 1 per ha to ca. 6 per ha. Troops fission at ca. 15–25 individuals, or 6–10 females. Adult sex ratio has no apparent correlation with fissions, birth rate or survival. Birth rate falls steeply with number of adult females, from 80–100% in 2-female troops to about 50% in 8–10 female troops. The penalty for large troop size is greater in the dense, rich areas, but nonetheless troops there are also larger. One-year-survival does not vary with troop size, and is lower in the sparse, dry zone. Troop size is too large for optimal birth rate, but fissioning to much lower size might make troops too small for optimal adult survival, given the intense intertroop competition. This reflects Sibley's (1983) conjecture that troop sizes may not reach stable optima. Rainfall per lemur-year (beginning Oct 1) varied from 265 to 894 mm. Drought followed by rain can eliminate >90% of a cohort, especially in the dryest zone. Possibly this results from fruit failure in years following drought. It is unknown whether food supplementation of some Berenty troops is dangerous for the forest, or helpful for an isolated and vulnerable ring-tailed lemur population.     

Population ecology of the ring-tailed lemur, Lemur catta, and the white sifaka, Propithecus verreauxi verreauxi, at Berenty, Madagascar, 1981

The diurnal lemurs Propithecus verreauxi verreauxi and Lemur catta at Berenty in southern Madagascar, have been studied for the last 30 years. The August 1981 census indicates that the population size of L. catta remains stable at 150 adults but that P. v. verreauxi troops have become fragmented and scattered and the population is apparently increasing. Eight different vegetation types were classified within the reserve and their influence on the distribution of L. catta and P. v. verreauxi investigated. Behavioural data obtained shows the niche separation between these two, potentially competitive, sympatric lemurs.     

New method to census primate groups: estimating group density of Japanese macaques by point census

We devised a new method to estimate the density of primate groups in habitats that preclude the use of a line-transect census because the ground is too steep. We combined point census and group follows. From the number of groups counted at a fixed point for an hour, n, group density D was calculated: D = lambda n / pi. Lambda, the detectability constant, was a constant when distance-dependent detectability g(y) was regressed on a half-normal model: g(y) = e (-lambda y(2)) and can be estimated by combining the information of group follow and point census. Using this method, we estimated the group density of Japanese macaques in Yakushima. A census area of 7 km(2) was divided into 28 grid squares (500 m x 500 m). One observer was positioned at a point in each grid square, and those points were censused simultaneously for 4-6 days from 0600-0700 to 1500-1600 hr. Four troops were followed for 144 hr during the point census. Distance-dependent detectability closely correlated with the half-normal model. The detectability constant varied with the time of day, but it was not influenced by troop identity or topography. Group density was calculated to be 1.48 +/- 0.61 and 0.701 +/- 0.432 groups/km(2) in the disturbed and undisturbed areas, respectively (95% confidence limit). "True" group density estimated by home range data was within the confidence limit calculated by a point census in the home range of the troops for two troops, suggesting that this method was valid. This method is applicable to other species as long as at least one group can be followed, because it satisfies the fundamental assumptions of point census, and the detectability does not seem to be biased by troop or topography.     

DISTRIBUTION AND POPULATION SIZE OF THE SOUTHERN SEA LION (OTARIA FLAVESCENS) IN CENTRAL AND SOUTHERN CHUBUT,PATAGONIA, ARGENTINA

Population size and distribution of Otaria flavescens in central and southern Chubut, Patagonia were determined by aerial censuses conducted during the breeding season in 1989 and 1995 and outside the season. Pup numbers were corrected by means of a linear regression between pup and adult male (AM) numbers obtained from terrestrial censuses carried out in 1994 and 1996. During the 1989 breeding season, 10,557 sea lions occurred at 29 locations; 2,800 (26.3%) were pups. During the 1995 breeding season, 14,887 animals were censused at 32 sites; 3,311 (22.2%) were pups. The corrected pup number increased to 4,852, indicating that around 32% is lost when counting from photographs. The corrected total number increased to 16,483; this fell to less than one half between breeding seasons (November 1990 and 1995). The 1995 breeding season census represents the highest number since 1972 (8,800) and the widest historical dispersion (37 sites year round contrasting with 13 in the late 1940s and 1972). However, the present number is about one half of the 33,000 censused about 50 yr ago. Using a correction factor developed for the north Paragonian population (1.8 × censused number) the present population size in the area can be estimated at around 29,669 individuals.     

Status and distribution of wandering, black-browed and grey-headed albatrosses breeding at South Georgia

Long-term studies at Bird Island, South Georgia, show that numbers of wandering, black-browed and grey-headed albatrosses have been decreasing since the late 1970s. To determine the status of the total South Georgia population, all known colonies were censused in 2003/2004 using a combination of yacht-based digital photography and ground counts. The breeding population estimates from this census are 1,553 pairs of wandering albatross, 74,296 pairs of black-browed albatross and 47,674 pairs of grey-headed albatross. A 30% decline since 1984 was recorded for wandering albatross, and comparison of a sample of black-browed and grey-headed albatross colonies on the mainland of South Georgia photo-censused in both 1985/1986 and 2003/2004 indicates similarly substantial population declines. Unless these decreases can be halted or reversed, doubt will exist as to the long-term viability of these species of albatross at South Georgia.     

Life history variables of wild troops of formosan macaques (Macaca cyclopis) in Kenting,Taiwan

A study on population dynamics of wild Formosan macaques (Macaca cyclopis) in Kenting, southern Taiwan, was conducted from March 1985 to August 1990. At first, only one monkey troop was studied. It fissioned in 1987 and both of the daughter troops have been observed since then. Total number of animals increased from 10 to 29 over the years, but the sizes of individual troops have never been more than 20. Seasonality in breeding has been detected: copulations were concentrated in the period from November to January and 75% of all the 28 births occurred between April and June. Time of birth by parous females without offspring from the preceding year was earlier than that of lactating females. Young females gave their first births at 4 or 5 years of age. Total birth rate over the study period was 0.8 infant per female per year. Hunting was the main cause of death while natural mortality rate was low for the animals. There was only one adult male in each troop for most of the time. Troop males in the two daughter troops have been replaced two or three times in the three years by some solitary males that moved around in the area. The reproductive parameters of Formosan macaques in Kenting were found to be more similar to that of rhesus monkeys than to Japanese macaques. And a case of higher reproductive success in a high-ranking matriline was reported.     

Resource use of Japanese macaques in heavy snowfall areas: implications for habitat management

Populations of Japanese macaque (Macaca fuscata) that inhabit the northernmost distribution of any nonhuman primates have been listed as endangered in Japan; however, macaques are widely known for being pests that cause agricultural damage. This study identified priority areas for the conservation and management of macaque habitats, by comparing the resource use of troops occupying remote mountains (montane troops) against troops inhabiting disturbed forests adjacent to settlements (rural troops). We collected species presence data across 2 years by radio-tracking two montane troops and two rural troops in the Shirakami Mountains. We developed seasonal utilization distributions by using the kernel method, and identified habitat characteristics by using ecological-niche factor analysis (ENFA). Our results indicate that environmental factors influencing the potential habitat varied widely with season in montane troops as compared with that in rural troops. ENFA results demonstrated that rural troops exhibited more biased resource use and narrower niche breadths than montane troops. Based on our findings, we propose that (1) primary broadleaf forests are the spring habitat conservation priority of montane troops; (2) the habitat unit—the product of habitat suitability index and its surface area—for montane troops is enhanced by removing old conifer plantations from the forest edge at low elevations; (3) such removal around settlements may also contribute toward removing a frontline refuge for rural troops intruding farmlands; and (4) intensive prevention measures against macaque intrusions into settlements during the bottleneck snowy season contribute toward reducing the habitat unit of rural troops.     

Nesting Behavior of Chimpanzees: Implications for Censuses

Chimpanzees have been censused using nest counting techniques since the mid 1970s. The use of nest counts makes several assumptions which have never been tested: (a) that the visibility of nests does not change with the height of the nest in the canopy; (b) that weaned chimpanzees construct on average one nest per day; (c) that establishing census lines has no effect on the nesting behavior of the chimpanzees; and (d) that the presence of snare injuries, common in forests in eastern Africa, does not affect nest construction. Tests of these assumptions in the Budongo Forest in Uganda showed that visibility of nests at different heights in the canopy is not different from the true distribution of nests but that the other assumptions are false. Minimizing human use could limit the effects of line transects on censuses, but the other two assumptions need to be corrected for.     

A normative construction of Gulf War syndrome

In early 1992, U.S. troops returning from the Gulf War began reporting a variety of nonspecific symptoms such as fatigue, skin rash, headache, muscle and joint pain, and loss of memory.These reports marked the beginning of what was to be identified as the Gulf War Syndrome (GWS). In the years since the war, as many as 100,000 troops have claimed they suffer from this mysterious disease. In our culture, the existence of disease as a specific entity is fundamental to ensuring the validity of that disease.The legitimacy of GWS has been repeatedly called into question because no specific physiological etiology has been confirmed, and it is becoming more and more likely that the origin of GWS will never be clearly delineated. The purpose of this paper is to illustrate the complicated process of defining GWS as a legitimate illness in the absence of etiological evidence and to suggest a method of treatment for individuals who still suffer from its sequelae.     

Population organization of wild pig-tailed macaques (Macaca nemestrina nemestrina) in West Sumatra

A field study on wild pig-tailed macaques was conducted in West Sumatra, Indonesia, during three periods from January 1985 to February 1987. During the nine months of the first two periods, unprovisioned monkeys were traced and observed. During the eight months of the last period, monkeys were provisioned and observed mainly at baiting sites. Three troops and ten solitary males appeared at the two baiting sites. Some males immigrated into and emigrated from the troops. The troops had a multi-male multi-female composition. The size of the various troops was 74, 49, and 81 individuals, respectively, and the mean adult sex ratio in the troops was 1:6.3; that is, markedly biased towards females. The home ranges of two of the troops overlapped considerably. When the troops encountered each other at the baiting sites, a clear dominance relationship was recognized. The troops differed in their integration as ranging units: two of the troops did not form subgroups (temporary fission and fusion of each troop), while the other troop frequently split into subgroups. Recent field studies on pig-tailed macaques have suggested a multi-leveled society with harem-type unit groups. However, in the present study, the troops observed had neither a substructure similar to harem-type groups nor a superstructure that emerged as a result of fusion of the troops. The unit group of the pig-tailed macaques appears to be a multi-male, matrilineal group.     

Gm and Inv studies on baboons, Papio cynocephalus: analysis of serum samples from Kenya, Ethiopia and South Africa.

Serum samples from 526 baboons (Papio cynocephalus) from 10 troops from the Laikipia district of northern Kenya, from 60 baboons from two troops from the Awash National Park, central Ethiopia, and from 127 baboons from South Africa were tested for Gm and Inv allotypes. Four of the 10 troops from Kenya formed a western cluster and six formed an eastern cluster. The clusters were separated by approximately 10 miles. The samples were tested for Gm (1, 2, 3, 5, 6, 11, 13, 14, 15, 16, 17, 21, 24) and for Inv (1, 2, 3). All samples were negative for Gm (2, 6, 14, 16, 24). All from Kenya and Ethiopia were negative for Inv (2), and all were positive for Gm (11, 17) and for Inv (3). The south African samples differed from the others in that 10 were negative for Gm (11) and four were positive for Inv (2). Taking all animals into account, polymorphism was present for Gm (1, 3, 5, 11, 13, 15, 21) and for Inv (1, 2). No two Kenya troops had the same array of phenotypes or of haplotypes, but the four western troops were more similar to each other than to the six eastern troops. Three haplotypes were present in the eastern troops that were not present in the western troops and five were present in the western troops that were not present in the eastern troops. Five haplotypes appeared in at least some troops of each cluster of troops. The samples from each of the two troops from Ethiopia show the same three phenotypes but with significantly different frequencies. It is suggested that the variation in haplotype frequencies observed among the 10 troops from Kenya is the result of a founder effect deriving largely from fission of a large troop into two smaller troops. The data show that speculations about the evolutionary origin of the allotypes are premature. For most species, too few animals have been tested and except for those in this study their origins are not known. Finally, the samples have been from too restricted an area.     

Intertroop relationships among Japanese monkeys

Intertroop relationships among Japanese monkeys, which have been paid only scant attention for the past 20 years, are examined from several points of view. Japanese monkey troops are generally distributed in such a way as to concentrate locally, that is, to form a local concentration of troops (LCT). About 20% of the nomadic ranges of the troops within LCT's overlap; but in their natural state, they seldom approach but rather to avoid one another. From observations of intertroop encounters at Takasakiyama, where three troops are provisionized and use the same feeding place, it has been found that there exists a dominant-subordinate relationship among troops, that monkeys of each troop have a clear consciousness of belonging to their troop, and that monkeys of different troops rate one another on the basis of their capability. The frequency of male transfer between troops within LCT's is by far higher than between LCT's. In Japanese monkey society, a troop only is a social unit and a social order higher than a troop is not seen; however, it is not impossible to consider an LCT a consanguineally connected group by reason of the transfer of males among the troops within it.     

Determinants of biased sex ratios and inter-sex costs of reproduction in dioecious tropical forest trees

Estimates of the sex ratio and cost of reproduction in plant populations have implications for resource use by animals, reserve design, and mechanisms of species coexistence, but may be biased unless all potentially reproductive individuals are censused over several flowering seasons. To investigate mechanisms maintaining dioecy in tropical forest trees, we recorded the flowering activity, sexual expression, and reproductive effort of all 2209 potentially reproductive individuals within 16 species of Myristicaceae over 4 years on a large forest plot in Amazonian Ecuador. Female trees invested >10 times more biomass than males in total reproduction. Flowering sex ratios were male-biased in four species in ≥1 year, and cumulative 4-year sex ratios were male-biased in two species and for the whole family, but different mechanisms were responsible for this in different species. Annual growth rates were equivalent for both sexes, implying that females can compensate for their greater reproductive investment. There was no strict spatial segregation of the sexes, but females were more often associated with specific habitats than males. We conclude that male-biased sex ratios are not manifested uniformly even after exhaustive sampling and that the mechanisms balancing the higher cost of female reproduction are extremely variable.     

Genetic polymorphisms of blood proteins in the troops of Japanese macaques,Macaca fuscata: III. Erythrocyte carbonic anhydrase polymorphism inMacaca fuscata

In order to clarify the genetic relationships between troops of Japanese macaques, the authors have been looking for the genetic variation of blood proteins by electrophoretical technique. In this work the genetic variants of erythrocyte carbonic anhydrase isozymes of 1273 blood samples from 34 troops of this species were examined. The genetic polymorphisms were observed in several troops. The variable troops of CA I were Fukushima, Takasakiyama, Kohchi, Shimane, Shodoshima I, K, and T, Kashima, Kawara, Takasakiyama A, B, and C, and Tomogashima. The variant allele found in these troops is onlyd ₂ allele, which was probably identical with that reported byTashian et al. (1971). The frequencies ofd ₂ allele in the Shodoshima and Kashima troops were very high, and this phenomenon was interpreted as being a result of the founder effect and the random fluctuation of gene frequencies in these troops.