Search results for Animal behaviour

Summary

OVERVIEW

Chimpanzee social interactions involve a rich repertoire of body movements and postures, autonomic indicators of arousal, vocal and nonvocal sounds, and facial expressions. Scores of regularly observed expressive physical behaviors have been described for wild chimpanzees, and comprehensive catalogs continue to grow as new behaviors are identified, because they are either rare, site-specific, or recently invented. Similarly, building on a basic repertoire of calls described in early field studies, researchers continue to distinguish new vocalizations as acoustic analyses reveal subtle variants within previously delineated call categories. Nonvocal sounds, made by striking, scratching, or otherwise manipulating body parts or objects in the environment, are commonly produced and offer seemingly limitless opportunities for innovation.

Expressive behaviors can be categorized according to the sensory modality they involve, that is, either olfactory, tactile, visual, or auditory. They are considered communicative “signals” insofar as they appear to have evolved to convey information to other individuals and to mediate social interactions. When signals are perceived through only a single sensory channel, they are comparatively easy to investigate. This is the case, for example, with loud vocalizations produced and monitored by individuals who are not in sight of one another. However, most chimpanzee interactions involve multimodal combinations of signals directed toward individuals that are in view. For example, it is common to observe a female approach and ultimately touch a male while she simultaneously crouches, bobs her head, and utters submissive vocalizations. Such multimodal events are more challenging to interpret, since it is difficult in practice to disentangle the functional consequences of their individual or variously combined components.

Animal communication is a social phenomenon, and analysis of communicative events necessarily requires consideration of both signalers and receivers. Classic descriptions of animal communication define the “message” of a signal as the information content of the signal itself. In this view, messages primarily consist of information about the sender. Potential information might include species, social group, individual identity, sex, status, physical condition, or motivational state. The “meaning” of a signal is its message combined with information available from the context of its production, and it is operationally defined in terms of the receiver's behavioral response. By combining message with context, receivers then have information available to predict the sender's probable imminent behavior and respond appropriately.

Summary

When the renowned fossil hunter Louis Leakey arranged for Jane Goodall to begin her field study of wild chimpanzees in East Africa, he hoped that her observations would shed light on the evolution of human ancestors. In the nearly six decades since, chimpanzees have become the most studied nonhuman mammal species in the wild and our primary model for thinking about how the last common ancestor of chimpanzees and humans may have behaved. The list of intriguing discoveries about these African apes is long and still growing: wild chimpanzees are prodigious tool users, they form and manipulate coalitions to achieve social status, they hunt in groups for large mammal prey, they occasionally kill their neighbors, and they exhibit persistent group-level differences that are reminiscent of human cultural variation, to name a few of their most notable features. Revelations such as these offer important clues about the early stages of an evolutionary voyage that would lead to modern Homo sapiens, the most intelligent and socially complex animal in the history of life.

How sobering, then, to contemplate that these intelligent and socially complex apes, our closest relatives in the animal kingdom, are poised for extinction in their natural habitat. Chimpanzees form large, mixed-sex groups, or “communities,” that aggressively defend extensive feeding territories where they find the ripe fruits that constitute the mainstay of their diet. When they reach sexual maturity, females typically disperse from these groups to breed in neighboring communities. In order for genetically viable populations to thrive, therefore, chimpanzees require intact forest areas that encompass multiple contiguous territories between which females can move. Habitat loss and fragmentation inevitably have devastating effects on chimpanzee populations, reducing food supplies, constricting mating opportunities, and forcing lethally antagonistic groups either into close contact with one another or into fringe habitats where they have access to only remnant patches of forest. Since the equatorial African rain forests on which chimpanzees rely continue to be harvested for timber and cleared for agriculture, their survival prospects are truly grim.

Long-term research projects play a key role in chimpanzee conservation efforts. Protecting chimpanzee populations relies partly on having detailed and comprehensive information about their social behavior, their ecological requirements, and the limits of their social and ecological flexibility. Since chimpanzees are long-lived animals and tropical forest habitats vary greatly and change over time, this necessitates the establishment and maintenance of decades-long field studies.

Summary

HABITUATING, FINDING, AND FOLLOWING CHIMPANZEES

Wild chimpanzees flee from people if they are unaccustomed to seeing them. If they are tracked persistently and unobtrusively, however, they will gradually become used to the presence of human observers. This process of “habituation,” in which the animals increasingly ignore unobtrusive onlookers, progresses through several stages. In the early phases, individuals feeding in the safety of the forest canopy will tolerate being watched from below but will quickly run once they descend to the ground to travel. Some months later, they may tolerate being quietly followed as they travel on the ground to a new feeding area, provided the observers remain twenty or thirty meters away. Some individuals may even rest and socialize on the ground in view of onlookers, as long as the humans keep their distance. As habituation continues, some animals begin to come within five to ten meters, perhaps passing by a researcher to approach a grooming partner, but will still move away if the researcher tries to approach them to that distance. Finally, after years of being tracked, most chimpanzees appear to ignore observers completely as they pursue their daily activities. At this stage, now fully habituated, they may literally brush past a researcher as they make their way along a path.

The most desirable data on wild chimpanzees are collected from fully habituated populations that are otherwise largely shielded from contact with humans. There are several reasons for this. First, researchers do not want their presence to affect the behavior of the animals they are watching. This appears to be achieved after complete habituation, when study animals show no visible fear of humans and engage in routine social and subsistence behaviors without looking at or otherwise directing behavior toward observers. Although chimpanzees everywhere have probably been influenced to some degree by human contact (people enter forests regularly for a variety of reasons – to collect firewood, edible plants, and medicinal plants; to hunt game, including chimpanzees at some locations; to extract lumber; to find refuge during warfare; and so on), habituated animals in protected areas nevertheless appear to offer an accurate picture of chimpanzee life unaltered by human influence.

Summary

OVERVIEW

The social lives of chimpanzees are influenced by how and with whom they compete for the resources necessary to their survival and reproduction. For females, this primarily means vying with other females for feeding locations within the community territory. In general, female–female competition occurs on a one-to-one basis, with individuals prevailing over or submitting to each other based on infrequent and low-level aggressive interactions. Although females are at times overtly friendly with one another and occasionally may form temporary coalitions to attack other females, on a daily basis they are largely indifferent to each other. Instead, adult females devote most of their social energy to nurturing and protecting their dependent offspring, who will forage, rest, and sleep with them for many years. Thus, female social life is characterized mainly by intensely supportive relationships with close relatives, competitive though occasionally friendly associations with other females, and deferential relationships with adult males.

Male existence, by contrast, revolves around both within- and between-community rivalry with other males for status, territory, and access to sexually receptive females. More so than for females, consequently, their social lives are shaped by a complicated mixture of competition and cooperation. On the one hand, males regularly patrol and defend territorial boundary areas together. Violent and sometimes lethal territorial aggression, in which several males from one community cooperate to attack isolated individuals from a neighboring community, has been observed at all study sites (Chapter 8). Meanwhile, the same males that join forces in dangerous territorial interactions also compete vigorously against each other for dominance status within their own communities. Although dominance conflicts are usually resolved through one-on-one aggressive interactions, they too can involve coalitions, are sometimes extremely violent, and can be lethal. Thus, relationships among males embody a delicate balancing act, with individuals committing large amounts of time to friendly interactions while also intermittently engaging in escalated aggression with each other to achieve dominance status.

Male behaviors toward females, on the other hand, are oriented more toward gaining long-term sexual access than creating supportive social bonds. Males form coalitions much less frequently with females than they do with males and, correspondingly, spend less time directing affiliative behaviors toward females. Meanwhile, despite the fact that their relative ranks are never in question, males frequently direct seemingly unprovoked aggression toward both cycling and non-cycling females.

Summary

The mammalian order Primates includes roughly 500 species, most of which are found in the tropics. As a group, primates are characterized by a constellation of traits that reflect adaptations to arboreal habitats, dietary flexibility, and extensive parental care. Not every trait is present in every species, and when they are present, most traits are expressed to varying degrees in different groups. Nevertheless, all primates possess most or all of the following:

Fertilization success will determine the rate at which a population can expand and is especially important when considering small, establishing or enduring communities. Introduced species frequently fail to establish reproductively functional populations due to strong Allee effects associated with low densities. The native European oyster, Ostrea edulis broods its fertilized eggs in the pallial cavity for a period of 8–10 days before releasing the larvae. It is considered a partial broadcast spawner and was used as a model species to assess the importance of Allee effects such as inter-individual distance on reproductive success. Distances between individual oysters within test plots in areas of known oyster density were used in conjunction with standardized brood size (n larvae g−1 total wet weight) to assess fertilization success. A significant, positive relationship was observed between brood size and oyster density. Oysters with a nearest neighbour ≤1.5 m were found to brood significantly more larvae than individuals with nearest neighbours ≥1.5 m. Therefore, high density sites need to be maintained to ensure the recovery and enhancement of this OSPAR Convention recognized species in decline.

As our closest primate relatives, chimpanzees offer tantalizing clues about the behavior of early human ancestors. This book provides a rich and detailed portrait of chimpanzee social life in the wild, synthesizing hundreds of thousands of hours of research at seven long-term field sites. Why are the social lives of males and females so different? Why do groups of males sometimes seek out and kill neighboring individuals? Do chimpanzees cooperate when they hunt monkeys? Is their vocal behaviour like human speech? Are there different chimpanzee 'cultures'? Addressing these questions and more, Adam Arcadi presents a fascinating introduction to the chimpanzee social universe and the challenges we face in trying to save this species from extinction. With extensive notes organized by field site and an appendix describing field methods, this book is indispensable for students, researchers, and anyone else interested in the remarkable and complex world of these intelligent apes.

Integrating developments from psychology, ethology and neuroscience, this is an undergraduate introduction to cognitive processes across species. The authors merge classic studies and contemporary research to give students a full picture of the evolving field of comparative cognition. Engaging students in the discipline from its roots in animal learning and evolutionary biology through to current research, the chapters cover both controlled laboratory and comparative cross-species studies in the natural environment. This approach provides students with complementary ethological and neurobiological perspectives on cognition. Feature boxes encourage active and engaged learning, giving a deeper understanding of topics discussed in the main text. These are supported by end-of-chapter questions to check understanding and encourage wider thinking around topics. Online resources include solutions to questions in the book, advanced material, PowerPoint lecture slides and additional questions, all available at www.cambridge.org/cognition.

During the period from April to September for the years 2014–2016, 998 swordfishes caught by the Moroccan artisanal longline fishery in the Strait of Gibraltar were sampled to study the reproduction of this species in this mixing area between the Mediterranean Sea and the North Atlantic. The results showed that the sex ratio is slightly in favour of males for sizes smaller than 130 cm LJFL (Lower jaw-fork length), whereas females are more numerous in sizes larger than 140 cm LJFL. Fifty per cent of females were estimated to be mature at 170 cm LJFL, while for males, the size at first maturity was estimated to be 95 cm LJFL. The swordfish spawn from June to September, probably in the Mediterranean Sea. The findings of this study suggest that the reproductive characteristics of swordfish caught in the Strait of Gibraltar are similar to those of the Mediterranean swordfish, and a high mixing rate between the Mediterranean and the North Atlantic stocks occurs in the study area.

This paper provides data on diversity, zonation and seasonal fluctuations of decapod crustaceans at the northern Gulf of Oman coast, based on quantitative and qualitative samplings. A total of 75 species belonging to four infraorders, 27 families and 48 genera were identified. These species include 20 new records for the entire Gulf of Oman and 13 new records for its Iranian coast. The mid-intertidal zone showed a higher mean diversity and abundance than high- and low-intertidal zones. The mean diversity and abundance in the high-intertidal zone showed significant differences with the mid- and low-intertidal zones. The indices of species richness (Margalef), diversity (Shannon) and evenness (Pielou) showed significant differences among the intertidal zones. Most of the identified species (>60%) that had high values in their frequency of occurrence and relative abundance showed an overlapping vertical distribution, and were present in all three or just in two of the three defined zones. Other species were found only in one of the three zones (non-overlapping vertical distribution). The decapod community in the mid-intertidal zone showed a higher dissimilarity with the high-intertidal zone than with the low-intertidal. Both abundance and diversity were found to be lowest and highest during south-west and north-east monsoons, respectively. During south-west monsoon, the abundance of decapods declined dramatically, but species diversity and ecological indices did not show any statistically significant difference among the sampling periods.

Sampling at four salmon aquaculture sites along the west coast of Scotland has identified short-lived aggregations of planktonic hydrozoans (>280 individuals m−3), here termed blooms. Several such blooms were linked with increases in gill pathology and mortality in caged fish. Two types, Obelia sp. and Lizzia blondina, were found to cause blooms regularly and often concurrently. Species composition of hydrozoan populations and fluctuations in population sizes were spatially and temporally heterogeneous, with adjacent sites (within 30 km of one another and with similar oceanic exposure) experiencing no correlation between species composition and population density. Blooms appeared temperature-mediated, with all identified blooms by Obelia sp. and L. blondina taking place in water above 12 °C; however, temperature alone was not found to be predictive. Blooms were not significantly associated with change in salinity, water clarity, or photoperiod. Due to the apparent lack of broadly applicable predictors, we suggest that localized, targeted sampling and examination of planktonic hydrozoan populations is required to discern the presence or absence of a bloom. It is likely that many blooms have historically caused harm in salmon aquaculture while remaining unrecognized as the root cause.

This study describes the structure, growth, mortality and stock status of Litopenaeus schmitti in north-eastern Brazil. A total of 1169 specimens were captured (491 males and 678 females) from August 2011 to July 2012. Specimens were weighed and the length of carapace (CL) and total length were measured. The biometric relationships were estimated through regression analysis and growth was described through the von Bertalanffy model. Additionally, total mortality (Z), natural mortality (M), fishing mortality (F), length at first capture (Lc), maximum yield per recruit (ERMY) and longevity were determined. Females were larger (3.07 ± 0.51 cm) than males (2.68 ± 0.25 cm) and dominant in the largest CL classes. The biometric relationships for males, females and both sexes grouped showed a negative allometric growth. Females showed larger L∞ (asymptotic length) and k (coefficient of growth) (L∞ of 5.00–5.16 cm and k of 1.20–1.26 year−1) when compared with males (L∞ of 4.25–4.30 cm and k of 1.00–1.02 year−1). In general, the mortality of males (Z = 1.93–5.48 year−1; M = 1.59–1.61 year−1 F = 0.32–0.3.89 year−1) and longevity (1.11–2.16 years) were higher than those estimated for females (Z = 1.84–3.76 year−1; M = 1.70–1.77 year−1; F = 0.07–1.99 year−1; 1.07–1.78 years). Results indicated that L. schmitti stock is relatively close to the state of full exploitation. Moreover, the CL of first capture of females (2.44–2.51 cm) is below the length of first sexual maturation of the species. The lack of legislation governing shrimp fishing in the area makes this stock even more vulnerable.

During the INDEMARES/CHICA 0610, 0211 and 0412 expeditions, carried out in the northern Spanish sector of the Gulf of Cádiz (Spain), samples were collected with a box-corer in 11 mud volcanoes and their adjacent bottoms. Chemoautotrophic communities were found in nine mud volcanoes. Among Decapoda, a rare eucalliacid, belonging to the genus Calliax and related to the Mediterranean infralittoral species C. lobata (de Gaillande and Lagardère 1966), was present in three of them. Data on its morphology, biogeographic distribution, vertical distribution within the burrows, sediment composition, pH and redox potential values (each in 5 cm intervals) are given; information on the chemoautotrophic communities associated with this species are also provided.

Rock oysters of the genus Saccostrea are the dominating group of filter-feeding communities on rocky beaches worldwide. The edible rock oyster (Saccostrea cucullata) is used as food and fish bait along the Indian coast. Morphometric analyses of S. cucullata from Baindur, Karnataka (India) were performed from June 2010 to May 2011, aiming to establish relationships between length and weight (total weight, shell weight, meat wet weight and meat dry weight). Morphometric relationships between length (L)-breadth (B) and length (L)-width (W) were B = 6.4952 + 0.4619 L and W = 3.1806 + 0.3276L, respectively. The equations of the length (L)-total weight (TW), length (L)-shell weight (SW), length (L)-meat wet weight (WW) and length (L)-meat dry weight (DW) were TW = 0.001227L2.3973, SW = 0.001165L2.3164, WW = 0.000037L2.1327 and DW = 0.000030L2.3289, respectively. The allometric growth pattern revealed changes in shell shape and weight variation throughout ontogeny in rocky habitats. The condition index and meat yield of S. cucullata exhibited seasonality, with higher values recorded during the periods post-monsoon and pre-monsoon.

Animal behaviour

Refine search

Refine search

Actions for selected content:

16142 results in Animal behaviour

1 - Primates, Apes, and the Study of Chimpanzee Social Behavior

Plate Section (PDF Only)

10 - Communication: The Form and Content of Signals

Summary

Preface

Summary

Appendix: Field Methods for Studying Wild Chimpanzees

Summary

Index

6 - Male Social Relationships

Summary

1 - Primates, Apes, and the Study of Chimpanzee Social Behavior

Summary

The importance of population density and inter-individual distance in conserving the European oyster Ostrea edulis

MBI volume 98 issue 4 Cover and Front matter

Editorial

MBI volume 98 issue 4 Cover and Back matter

Wild Chimpanzees

Comparative Cognition

The reproductive biology of swordfish (Xiphias gladius) in the Strait of Gibraltar

Quantitative analyses of decapod crustaceans at a rocky intertidal shore in the Gulf of Oman, Iran: diversity, zonation and monsoonal fluctuations

Cryptic hydrozoan blooms pose risks to gill health in farmed North Atlantic salmon (Salmo salar)

Population dynamics of the white shrimp Litopenaeus schmitti (Burkenroad, 1936) on the southern coast of Pernambuco, north-eastern Brazil

Decapod crustaceans Eucalliacidae in chemoautotrophic bathyal bottoms of the Gulf of Cadiz (Atlantic Ocean), environmental characteristics and associated communities

Biometrics, condition index and meat yield of edible rock oyster, Saccostrea cucullata (Born, 1778)

Animal behaviour

Refine search

Refine search

Actions for selected content:

Save Search

16142 results in Animal behaviour

Summary

Summary

Summary

Summary

Summary

Wild Chimpanzees

Comparative Cognition