Vervet Monkey Alarm Calls: Manipulation Through Shared Information?

Behaviour ◽  
1985 ◽  
Vol 94 (1-2) ◽  
pp. 150-166 ◽  
Author(s):  
Dorothy L. Cheney ◽  
Robert M. Seyfarth

AbstractHigh-ranking male and female vervet monkeys in Amboseli National Park alarm-call at higher frequencies than do low-ranking males and females. This correlation between rank and alarm-calling does not occur because high-ranking animals have more offspring or close kin than low-ranking animals. Similarly, high-ranking animals do not seem to have greater opportunities to spot potential predators; they do not scan the habitat more than low-ranking animals, nor are they more likely to be in the forefront of group progressions. It seems possible that low-ranking animals may spot predators as often as high-ranking animals, but that they do not always alert other group members to approaching danger. As a further test of the possibility that monkeys may vary the rate of alarm-calling depending on social contexts, an experiment was conducted on captive vervet monkeys in which adult females were presented with a predator in the presence of either their offspring or an unrelated juvenile. Adult females alarm-called significantly more often when with their offspring than with unrelated juveniles. A similar experiment conducted on adult males showed that males alarm-called at higher rates in the presence of adult females than in the presence of other adult males. The results of both experiments and observations suggest that monkeys may vary the rate at which they warn others of danger. The withholding of information may be an effective means to deceive others, because it is relatively difficult to detect cheaters. The possible advantages of selectivity in alarm call production are discussed.

Behaviour ◽  
1981 ◽  
Vol 76 (1-2) ◽  
pp. 25-60 ◽  
Author(s):  
Dorothy L. Cheney ◽  
Robert M. Seyfarth

AbstractVervet monkeys in Amboseli National Park, Kenya are preyed upon by four types of predator: mammalian carnivores, eagles, baboons, and snakes. Over a 14 month period, adult males and females gave first alarm calls at comparable rates. Both observation on the frequency of alarm-calling and experiments on the duration of alarm-calling indicated that high-ranking adult males and females gave alarm calls more often than low-ranking adult males and females. Individuals who alarm-called most often did not vocalize most often during social interactions, nor did they spend more time than others surveying the habitat around them. There was some tendency, however, for females who alarm-called most often to precede other females in group progressions. Limited evidence suggests that adult males who gave most alarm calls were more likely than other males to have fathered the group's juveniles and infants. Among adult females, however, there was no correlation between number of offspring and frequency of first alarm calls. Females who gave alarm calls most often were not more likely than other females to spend large proportions of observation time more than 2 m from their offspring. Data on a small sample of confirmed predatory attacks suggest that the offspring of high-ranking females may have been more vulnerable than other immatures to predation. Such differential vulnerability may have resulted in part from the tendency of the offspring of high-ranking females to precede other juveniles in group progressions. Vervets of all age/sex classes alarm-called most at those species of predators to which they themselves seemed to be most vulnerable. Adult vervets gave relatively few alarm calls to predators to which their offspring, but not themselves, were vulnerable, even though such alarm calls would have been of low cost to themselves and of great potential benefit to their offspring. While some aspects of the alarm-calling behavior of vervet monkeys are consistent with the hypothesis that their alarms have evolved to benefit kin, in other respects their alarms appear to have the consequence of benefitting only the alarmists themselves. It is likely that both kin and individual selection, acting on an individual's inclusive fitness, have played a role in the evolution of vervet monkeys' alarm calls.


Behaviour ◽  
2016 ◽  
Vol 153 (5) ◽  
pp. 591-606 ◽  
Author(s):  
Lynne A. Isbell ◽  
Laura R. Bidner

Behavioural predator–prey interactions are difficult to study, especially when predators avoid humans. To gain greater understanding of their dynamism, we conducted a 14-month field study in which we minimized human presence by employing acoustic recorders and camera traps, along with GPS collars deployed on vervet monkeys (Chlorocebus pygerythrus) and leopards (Panthera pardus) in Laikipia, Kenya. Recordings at the vervets’ sleeping site revealed that they gave ‘leopard’ alarm calls most frequently near dusk and dawn, whereas photographs showed that leopards approached vervets more closely at night, when the monkeys alarm-called less often. GPS data showed that after vervets alarm-called, leopards within 200 m quickly moved away, changing direction, but when vervets did not alarm-call, leopards continued moving forward. These results reveal that vervets’ leopard alarm calls function as a predator deterrent in addition to a conspecific warning call.


Zootaxa ◽  
2011 ◽  
Vol 2983 (1) ◽  
pp. 39 ◽  
Author(s):  
IVAN L. F. MAGALHÃES ◽  
ADALBERTO J. SANTOS

In this paper, M. yanomami n. sp., from Brazilian Amazonia, Chaetacis bandeirante n. sp., from Central Brazil, and the males of M. gaujoni Simon, 1897 and M. ruschii (Mello-Leitão, 1945) n. comb. , respectively from Ecuador and Brazil, are described and illustrated for the first time. An ontogenetic series of the last development stages of both sexes of Micrathena excavata (C. L. Koch, 1836) is illustrated and briefly described. Adult females are larger and have longer legs and larger abdomens than adult males. Probably females undergo at least one additional moult before adulthood, compared to males. Micrathena ornata Mello-Leitão, 1932 is considered a junior synonym of M. plana (C. L. Koch, 1836), and M. mastonota Mello-Leitão 1940 is synonymized with M. horrida (Taczanowski, 1873). Acrosoma ruschii Mello-Leitão, 1945 is revalidated, transferred to Micrathena and considered a senior synonym of M. cicuta Gonzaga & Santos, 2004. Chaetacis necopinata (Chickering, 1960) is recorded for Brazil for the first time. Chaetacis incisa (Walckenaer, 1841) is considered a nomen dubium.


1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero

Seasonal spacing patterns, home ranges, and movements of river otters (Lontra canadensis) were studied in boreal Alberta by means of radiotelemetry. Adult males occupied significantly larger annual home ranges than adult females. Males' ranges overlapped those of females and also each other's. In winter, home ranges of males shrank and showed less overlap. Otters often associated in groups, the core members typically being adult females with young, or adult males. Otters tended to be more solitary in winter. In winter, movement rates of all sex and age classes were similar, and much reduced for males compared with those in other seasons. These data indicated a strong limiting effect of winter ice on behaviour and dispersion. We tested the hypothesis that otters select water bodies in winter on the basis of the suitability of shoreline substrate and morphology for dens with access both to air and to water under ice. Intensity of selection was greatest in winter, with avoidance of gradually sloping shorelines of sand or gravel. Adults selected bog lakes with banked shores containing semi-aquatic mammal burrows, and lakes with beaver lodges. Subadults selected beaver-impounded streams. Apart from human harvest, winter habitats and food availability in such habitats are likely the two factors most strongly limiting otter density in boreal Alberta.


Behaviour ◽  
1980 ◽  
Vol 72 (1-2) ◽  
pp. 26-48 ◽  
Author(s):  
Patrick Duncan

AbstractTime-budgets of adult and weaned sub-adult horses were studied in a small population of Camargue horses living in semi-liberty. The categories of activities used were: Standing resting, Lying flat, Lying up, Standing alert, Walking, Trotting, Galloping, Rolling and Foraging. The main differences in time-budgets were related to age and to sex : young horses spent more time lying (sleeping), males spent more time standing alert and in rapid movements (trot, gallop), while usually foraging less than did the adult females. During the three years of the study the population increased from 20 to 54 horses and there were considerable changes in social structure as the number of adult males increased. Associated with these developments there were some changes between years in the time-budgets: the most striking of which was a general trend for all horses to spend less time lying. Nonetheless the time-budgets showed a considerable constancy across years and age/sex-classes, especially with regard to time spent foraging. This conclusion may provide a clue as to why horses have an unusual social system based on long term relationships between a male and the females of his harem.


2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Paul J. Ode ◽  
Dhaval K. Vyas ◽  
Jeffrey A. Harvey

The diverse ecology of parasitoids is shaped by extrinsic competition, i.e., exploitative or interference competition among adult females and males for hosts and mates. Adult females use an array of morphological, chemical, and behavioral mechanisms to engage in competition that may be either intra- or interspecific. Weaker competitors are often excluded or, if they persist, use alternate host habitats, host developmental stages, or host species. Competition among adult males for mates is almost exclusively intraspecific and involves visual displays, chemical signals, and even physical combat. Extrinsic competition influences community structure through its role in competitive displacement and apparent competition. Finally, anthropogenic changes such as habitat loss and fragmentation, invasive species, pollutants, and climate change result in phenological mismatches and range expansions within host–parasitoid communities with consequent changes to the strength of competitive interactions. Such changes have important ramifications not only for the success of managed agroecosystems, but also for natural ecosystem functioning. Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


PEDIATRICS ◽  
1978 ◽  
Vol 62 (1) ◽  
pp. 90-90
Author(s):  
Martin Harris

According to a demographic survey of over 600 primitive populations carried out by William T. Divale of the American Museum of Natural History, there is an extraordinary consistent imbalance of boys over girls in the junior and infant age ranks (up to about 15 years old). [Divale says] that many primitive groups follow a practice of overt female infanticide. Female children are suffocated or simply left unattended in the bush. But more often infanticide is covert, and people usually deny that they practice it.... Warfare inverts the relative value of the contribution made by males and females to a group's prospects for survival. By placing a premium upon maximizing the number of combat-ready adult males, warfare obliges primitive societies to limit their nurturance of females. It is this, and not combat per se, that makes warfare an effective means of controlling population growth.... Lacking any safe and effective means of contraception or abortion, primitive peoples must focus their institutionalized means of population control on individuals who are already alive. Children are the logical victims of these efforts—the younger the better—since number one, they can't resist; number two, there is less of a social and material investment in them; and number three, the emotional ties to infants are easier to cut than those between adults. Anyone who finds my reasoning depraved or "uncivilized" should read about eighteenth-century England. Gin-soaked mothers by the tens of thousands regularly dropped their babies into the Thames or wrapped them in the clothing of smallpox victims, left them in trash barrels, rolled over on top of them during drunken stupors, and otherwise contrived to shorten their babies' lives by direct or indirect means.


1980 ◽  
Vol 58 (3) ◽  
pp. 461-463 ◽  
Author(s):  
R. E. Salter

Social interactions in walrus herds of mixed sex and age composition were recorded at a haul-out site on the east coast of Bathurst Island, N.W.T., during July–August 1977. Most walruses maintained body contact with at least one other walrus while hauled out on land; herds were usually circular in shape. Adult males, adult females, and immatures all displaced other walruses, and thus entered herds, by jabbing with the tusks. Dominance during agonistic interactions was related to relative tusk length and sex and age of interactants. Behaviour of walruses on land suggested an energetic advantage in mutual body contact, which would be maximized by occupation of interior positions within herds.


1958 ◽  
Vol 4 (6) ◽  
pp. 771-776 ◽  
Author(s):  
Mary L. Petermann ◽  
Mary G. Hamilton

Rat liver was homogenized in 0.88 M sucrose. The DNA and total RNA were determined, and the homogenate was fractionated by differential centrifugation. The pellets obtained between 30 minutes at 20,000 g and 180 minutes at 105,000 g were analyzed for RNA and nitrogen. The ribonucleoproteins were determined in the analytical ultracentrifuge. The non-pellet RNA was calculated by difference. The results are reported as amounts per 6.7 x 10-9 mg. of DNA. In young, growing male rats the amounts of microsomal protein and ribonucleoprotein B (83S) increased with age. Non-pregnant adult females showed less non-pellet RNA and much more ribonucleoprotein C (63S) than did adult males. During pregnancy both of these cell constituents reverted to levels characteristic for male animals. Starvation for 5 days resulted in a reduction in the mass of liver tissue, the non-pellet RNA, the microsomal protein, and ribonucleoproteins B and C. During recovery from starvation the return of the liver to normal paralleled the rate at which body weight was restored. Treatment with cortisone, 25 mg. per rat per day for 5 days, caused an increase in microsomal protein and a decrease in ribonucleoprotein B. Treatment with 6-mercapto-purine, 50 mg. per kilo per day for 5 days, caused little change in liver composition in either males or females.


1993 ◽  
Vol 27 (1) ◽  
pp. 59-64 ◽  
Author(s):  
F. S. Venter ◽  
H. Cloete ◽  
J. V. Seier ◽  
M. J. Faber ◽  
J. E. Fincham

Plasma and red blood cell (RBC) folic acid levels, as well as plasma vitamin B12 levels were determined in Vervet monkeys ( Cercopithecus aethiops). All the vervets were apparently healthy and without symptoms or lesions typical of folic acid and/or vitamin B12 deficiencies. Competitive protein binding radioassays were used to determine folate and vitamin B12 values in animals fed 4 different diets. The B12 levels for all the groups ranged between 866 and 5867 pg/ml and showed an inverse relationship with the FA measurements. The lowest mean RBC folic acid content in a group fed an atherogenic diet for 3 years was 12·8 ng/ml. For the other 3 diets, mean RBC folic acid levels were 90·7, 132·3 and 152·8 ng/ml, respectively. A megadose of 25·6 mg of folic acid per day for 99 days was given to 3 adult males. No obvious toxic effects were observed in these animals although mean RBC folic acid levels increased to 1013 ng/ml.


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