Hunting and fishing focus among the Miskito Indians,eastern Nicaragua

The amounts of native animals taken in hunting and fishing by Amerind peoples are almost unknown. The interrelationships of cultural and ecological systems determine to a large extent hunting and fishing returns, focus, and strategies. This study presents data obtained in a coastal Miskito Indian village in eastern Nicaragua. Measurements were made of meat yields by species and of the time and distance inputs involved in securing fish and game. Hunting and fishing focus and strategies are adaptive mechanisms enabling the Miskito to achieve high and dependable returns from a limited number of species. Several factors are examined which influence hunting and fishing focus: dietary preferences and prohibitions, costs involved, differential productivity and dependability of particular species, seasonality and scheduling, and the impact of cash market opportunities for faunal resources. Under the impetus of population growth and rising aspirations, the Miskito's efforts to secure increasing numbers of animals for both subsistence and market are leading to severe pressures on selected species and to cultural and ecological disruptions.This study is part of a larger project on Miskito subsistence ecology carried out in 1968–1969 with a grant from the Foreign Area Fellowship Program. Additional data were obtained May through August 1971, supported by a Social Science Research Council grant.     

Labor specialization and the formation of markets for food in a Shipibo subsistence economy

Traditionally, the Shipibo economy was subsistence-based with shifting cultivation supplying calories, principally in the form of plantains and root crops, while fishing and hunting provided animal proteins to the diet. Some men, who recently began producing rice for sale in regional markets, now allocate less time to wild food procurement. Moreover, this trend has been accompanied by the nucleation of households, a growing cash market for agricultural labor, and the intravillage sale of faunal foods. This paper shows that with cash cropping, some Shipibo now freely distribute less food to others in relation to the amount they produce. To account for this change, a theory is developed based on time allocation and patterns of economic behavior reported throughout the Amazon. This theory is then applied to explain specialization and the formation of cash markets for food labor among the Shipibo.     

Task Allocation Depends on Matriline in the Ponerine Ant Gnamptogenys striatula Mayr

Matriline and the predominant social tasks performed by workers are correlated in the functionally polygynous ponerine ant Gnamptogenys striatula. This result favors the idea that polygyny might have been secondarily selected and maintained in ants because it provided more genetic variability and, thus, more potential variation in the regulation of the division of labor within mutualistic societies. As in previous studies on ants, nepotism could not be demonstrated. Because of the relatively small number of individuals per colony, these ponerine ants constitute a valuable model for exploring how polyethism is determined in insect societies.     

Applying Behavioral Ecology and Behavioral Economics to Conservation and Development Planning: An Example from the Mikea Forest,Madagascar

Governments and non-govermental organizations (NGOs) that plan projects to conserve the environment and alleviate poverty often attempt to modify rural livelihoods by halting activities they judge to be destructive or inefficient and encouraging alternatives. Project planners typically do so without understanding how rural people themselves judge the value of their activities. When the alternatives planners recommend do not replace the value of banned activities, alternatives are unlikely to be adopted, and local people will refuse to participate. Human behavioral ecology and behavioral economics may provide useful tools for generating and evaluating hypotheses for how people value economic activities in their portfolios and potential alternatives. This is demonstrated with a case example from southwestern Madagascar, where plans to create a Mikea Forest National Park began with the elimination of slash-and-burn maize agriculture and the encouragement to plant labor-intensive manioc instead. Future park plans could restrict access to wild tuber patches, hunting small game, and fishing. The value of these activities is considered using observational data informed by optimal foraging theory, and experimental data describing people’s time preference and covariation perception. Analyses suggest that manioc is not a suitable replacement for maize for many Mikea because the two crops differ in terms of labor requirements, delay-to-reward, and covariation with rainfall. Park planners should promote wild tuber foraging and stewardship of tuber patches and the anthropogenic landscapes in which they are found. To conserve small game, planners must provide alternative sources of protein and cash. Little effort should be spent protecting lemurs, as they are rarely eaten and never sold.     

Influence of Chimpanzee Predation on Associations Between Red Colobus and Red-tailed Monkeys at Ngogo,Kibale National Park,Uganda

Colobines often associate with cercopithecines at various African sites. Such polyspecific associations presumably have an antipredation function. At Ngogo, Kibale National Park, Uganda, red colobus (Procolobus rufomitratus) spend considerable time in association with red-tailed monkeys (Cercopithecus ascanius), and they are also heavily hunted by chimpanzees (Pan troglodytes). I conducted behavioral observations and playback experiments to test the hypothesis that red colobus and red-tailed monkeys obtain mutual protection and predator-related benefits by associating. Despite high chimpanzee hunting pressure on red colobus and much lower hunting pressure on red-tailed monkeys, red-tailed monkeys initiate, maintain, and terminate the associations. The results suggest that rather than providing red colobus with protection against chimpanzees, the associations occur mostly because they protect red-tailed monkeys against predation by eagles.     

Sago production in a New Guinea economy

The techniques used by the Sanio-Hiowe of Papua New Guinea to produce edible starch from the sago palm (Metroxylon sp.) are described. Input-output analysis demonstrates that this is a highly productive subsistence technology; nevertheless, the Sanio-Hiowe economy is characterized by an absence of intensification. This is ascribed to functional consequences of dependence on hunting and gathering in the interior. In coastal and riverine habitats, other societies using sago supplemented by fishing or horticulture can more fully exploit the potential of sago as a basis for economic intensification and a more sedentary life.This field research among the Sanio-Hiowe of Yareno hamlet was carried out from March 1966 to August 1967 with the assistance of W. Townsend and the support of a National Science Foundation dissertation research grant and a United States Public Health Service Fellowship. In earlier publicationsHiowe was spelledHeve. I have altered the spelling of Sanio words to conform to the phonemic analysis of Lewis and Lewis (1970).     

Northwest Coast Halibut Hooks: an Evolving Tradition of Form,Function, and Fishing

The Northwest Coast (NWC) halibut hook is both an indigenous fishing technology, and an iconic object of rich cultural history. This study utilizes biological, statistical, ecological, and ethnographic data to examine the function(s) of NWC halibut hooks, and how and why dimensions are changing through time. Analyses of measurements from 143 specimens, dated from 1867 to 2015, suggest a statistically significant increase in overall length through time. These findings support the hypothesis that as the use of modern fishing technologies became more prevalent, and traditional NWC halibut hooks largely lost their original function (i.e., catching halibut), dimensions changed to favor decorative or symbolic content over utilitarian/functional requirements. Archival data, peer-reviewed literature, and ethnographic interviews with contemporary carvers and fishers support the assertion that average dimensions of early NWC halibut hooks targeted fish between 20 and 100 lbs., thus promoting sustainability of Pacific halibut breeding populations. Whether the hooks were designed intentionally to promote sustainability or this size of fish was targeted for other reasons remains an open question.     

Determinants of time allocation across the lifespan

This paper lays the groundwork for a theory of time allocation across the life course, based on the idea that strength and skill vary as a function of age, and that return rates for different activities vary as a function of the combination of strength and skills involved in performing those tasks. We apply the model to traditional human subsistence patterns. The model predicts that young children engage most heavily in low-strength/low-skill activities, middle-aged adults in high-strength/high-skill activities, and older adults in low-strength/high-skill activities. Tests among Machiguenga and Piro forager-horticulturalists of southeastern Peru show that males and females focus on low-strength/low-skill tasks early in life (domestic tasks and several forms of fishing), switch to higher-strength/higher-skill activities in their twenties and thirties (hunting, fishing, and gardening for males; fishing and gardening for females), and shift focus to high-skill activities late in life (manufacture/repair, food processing). Michael Gurven is an assistant professor of anthropology at the University of California-Santa Barbara. He received his Ph.D. from the University of New Mexico in 2000. He has conducted fieldwork in Paraguay and Bolivia with Ache and Tsimane forager-horticulturalists. His research interests include intragroup cooperation and problems of collective action, and the application of life history theory to explaining human longevity, cognitive development, delayed maturation, and sociality. Since 2002, Gurven and Kaplan have co-directed the Tsimane Health and Life History Initiative, a five-year project to develop theory and test implications of different models of human life history evolution. Hillard Kaplan is a professor of anthropology at University of New Mexico. He received his Ph.D. from the University of Utah in 1983. He has conducted fieldwork in Paraguay, Brazil, Botswana, and Bolivia. His research interests include evolutionary perspectives on life course development and senescence, and brain evolution. He has launched theoretical and empirical investigations into each of these areas, uniting evolutionary and economic approaches. He has applied human capital theory toward explaining human life history evolution, and the proximate physiological and psychological mechanisms governing fertility and parental investment in both traditional, high-fertility, subsistence economies and modern, low-fertility, industrial societies.     

The use of optimal foraging theory in the understanding of fishing strategies: A case from Sepetiba Bay (Rio de Janeiro State,Brazil)

The community of Gamboa is located on Itacuruçá Island, Sepetiba Bay (State of Rio de Janeiro, Brazil) and includes 26 families, mostly of artisanal fishermen who use paddled or motor canoes, and encircling nets for fishing. In this study, predictions from optimal foraging theory (patch model), in particular of patch residence time, are compared to the observed behavior of fishermen on fishing trips. Fishermen's strategies differ depending on their intended prey. They spend more time in patches and use fewer patches for shrimp than for fish. Gamboa's fishermen tend to leave a patch later than predicted by the model. The difficulty in evaluating stock availability, the comparatively few patches available for shrimp, and the competitive aspects of fishing contribute to the explanation of this behavior.     

Net hunters vs. archers: Variation in women's subsistence strategies in the Ituri Forest

BaMbuti of the Ituri Forest, Zaire, employ two primary hunting techniques: net hunting, in which women routinely participate, and bow hunting, in which women rarely participate. We hypothesize that the value of women's labor devoted to different subsistence activities, combined with the exchange value of meat, will determine whether women participate in hunts. Field observations were conducted in four different areas: two exploited by archers and two by net hunters. Results indicate that women in nethunting areas earn more calories per unit time by hunting than by working in agriculturalists' gardens; whereas women in archer areas earn more calories by working for agriculturalists than by hunting. We found no significant difference in the composition or diversity of the forests exploited by net hunters and archers. The results are discussed in light of the longstanding debate concerning the factors that account for distribution of net hunting and archery in the Ituri Forest.     

Changes in osteoarthritis associated with the development of a maritime economy among southern California Indians

The severity of osteoarthritis was studied in human skeletal remains from archaeological sites in the Santa Barbara Channel area of southern California. These remains were analyzed to better understand changes in activity patterns associated with the economic shift from hunting and gathering to intensive fishing and craft specialization that occurred in this area. The joints of 967 burials from seven archaeological sites occupied between 3500 B.C. and the time of European contact were scored for osteoarthritis. These data show that the rate at which people developed osteoarthritis increased through time. This suggests that the adaptive shift toward more intensive exploitation of the marine environment resulted in an increase in the time people spent in strenuous physical activity. The increase in osteoarthritis affected males to a greater extent than females. One interpretation of this is that the work load of men increased with the economic importance of fishing.     

Specialization Does Not Predict Individual Efficiency in an Ant

The ecological success of social insects is often attributed to an increase in efficiency achieved through division of labor between workers in a colony. Much research has therefore focused on the mechanism by which a division of labor is implemented, i.e., on how tasks are allocated to workers. However, the important assumption that specialists are indeed more efficient at their work than generalist individuals—the “Jack-of-all-trades is master of none” hypothesis—has rarely been tested. Here, I quantify worker efficiency, measured as work completed per time, in four different tasks in the ant Temnothorax albipennis: honey and protein foraging, collection of nest-building material, and brood transports in a colony emigration. I show that individual efficiency is not predicted by how specialized workers were on the respective task. Worker efficiency is also not consistently predicted by that worker''s overall activity or delay to begin the task. Even when only the worker''s rank relative to nestmates in the same colony was used, specialization did not predict efficiency in three out of the four tasks, and more specialized workers actually performed worse than others in the fourth task (collection of sand grains). I also show that the above relationships, as well as median individual efficiency, do not change with colony size. My results demonstrate that in an ant species without morphologically differentiated worker castes, workers may nevertheless differ in their ability to perform different tasks. Surprisingly, this variation is not utilized by the colony—worker allocation to tasks is unrelated to their ability to perform them. What, then, are the adaptive benefits of behavioral specialization, and why do workers choose tasks without regard for whether they can perform them well? We are still far from an understanding of the adaptive benefits of division of labor in social insects.     

Pollen evidence of localized impact on the vegetation of northernmost Finland by hunter-gatherers

Pollen data are presented for the pine forest region around Lake Inari in eastern Finnish Lapland. The region has traditionally been the home of the Saami people who, until the 19th century, followed a seasonally nomadic way of life with an economy based on hunting, fishing and gathering. Although the Saami had no permanent centres of settlement, they did gather together at specific sites every winter, revisiting them year after year over several decades. A pollen diagram is presented from a peat area adjacent to one such winter village, Einehlammet. This shows a clear interference phase characterized by a peak in Ericales followed by a small but distinct peak in Poaceae and the slight, sporadic occurrence of pollen types that can be shown to be connected with human presence. At the same time Pinus values fall and, at the end of the phase, there is a strong increase in Betula pollen. This evidence is compared with that from actually within a dwelling (kota) at another winter village, Nukkumajoki, and is seen to follow exactly the same pattern. Such changes in forest composition in this situation could not be attributed to climatic change. The results demonstrate that, peoples pursuing a purely hunting and gathering economy and moving in the forests in a manner designed to preserve rather than destroy their environment can, nevertheless, cause vegetation changes that are discernable by pollen analysis within a distance of 50 m.     

The effects of fisheries management on harvest rates of native and non-native salmonid fish species

In central Europe, both brown trout Salmo trutta and European grayling Thymallus thymallus are threatened native salmonid species with high value in recreational angling and nature conservation. On the other hand, rainbow trout Oncorhynchus mykiss and brook trout Salvelinus fontinalis are intensively stocked non-native species of high angling value but no value for nature conservation. This study tested if harvest rates of native salmonids are negatively correlated to intensive stocking and harvest rates of non-native salmonids in inland freshwater recreational fisheries. Data were collected from 250 fishing sites (river and stream stretches) over 13 years using mandatory angling logbooks. Logbooks were collected from individual anglers by the Czech Fishing Union in the regions of Prague and Central Bohemia, Czechia (central Europe) and processed by the author of this study. In result, anglers harvested 200,000 salmonids with total weight of 80 tons over 13 years. Intensive stocking of multiple salmonid species lead to slightly lower harvests of native salmonids. Inversely, intensive harvests of multiple salmonid species lead to slightly higher harvest of native salmonids. Recapture rates of stocked salmonids were relatively low (0.6%–3.7%), proving fish stocking moderately ineffective. Since the effects of non-native salmonid stocking and harvest rates on native salmonid harvest were significant but not strong, it is suggested that rivers and streams that support fishing for non-native salmonids still support fishing for native salmonids. However, this idea does not apply for fishing sites with really high intensity of non-native salmonid stocking – harvest rates of natives were very low on these fishing sites.     

The influence of environmental conditions on aspects of the time budgests of breeding ospreys

Summary Ospreys (Pandion haliaetus) were observed for 350 h in 1975 in southeastern Virginia. Other studies have demonstrated that weather can have an effect on aspects of osprey foraging behavior (e.g., frequency of diving), but for the environmental conditions observed in this study, weather and other variables did not appear to limit the ability of ospreys to feed their young.Male ospreys, which procure essentially all of the food for the family unit before the chicks fledge, spend an average of 43% of the daylight hours perched near the nest when they have unfledged young. About 1/3 of the daylight hours are utilized for hunting. Weather conditions have no effect on the time the male his perched near the nest, or on the rate of fish delivery by the male. Wind speed variability regressed positively with the time it took males to return with a fish (mean time=0.64 h/fish), but accounted for only 16% of the variation in the length of hunting trips. Size of fish delivered and rate of fish delivery were unrelated to either brood size or age of young. As the chicks age, the male spends increasing amounts of time away from the nest; this is not related to changes in weather, and appears to be due to decreasing attentiveness at the nest site by the male. Females with unfledged young spent over 95% of the daylight hours at the nest.Adults with fledged but dependent young spend an average of 1/3 of the day perched near the nest. Both adults deliver fish at this time, but together they bring no more than the male alone brought before fledging. For both adults neither the percentage of time perched near the nest nor the rate of fish delivery are related to weather conditions.     

Evolution of Self-Organized Task Specialization in Robot Swarms

Division of labor is ubiquitous in biological systems, as evidenced by various forms of complex task specialization observed in both animal societies and multicellular organisms. Although clearly adaptive, the way in which division of labor first evolved remains enigmatic, as it requires the simultaneous co-occurrence of several complex traits to achieve the required degree of coordination. Recently, evolutionary swarm robotics has emerged as an excellent test bed to study the evolution of coordinated group-level behavior. Here we use this framework for the first time to study the evolutionary origin of behavioral task specialization among groups of identical robots. The scenario we study involves an advanced form of division of labor, common in insect societies and known as “task partitioning”, whereby two sets of tasks have to be carried out in sequence by different individuals. Our results show that task partitioning is favored whenever the environment has features that, when exploited, reduce switching costs and increase the net efficiency of the group, and that an optimal mix of task specialists is achieved most readily when the behavioral repertoires aimed at carrying out the different subtasks are available as pre-adapted building blocks. Nevertheless, we also show for the first time that self-organized task specialization could be evolved entirely from scratch, starting only from basic, low-level behavioral primitives, using a nature-inspired evolutionary method known as Grammatical Evolution. Remarkably, division of labor was achieved merely by selecting on overall group performance, and without providing any prior information on how the global object retrieval task was best divided into smaller subtasks. We discuss the potential of our method for engineering adaptively behaving robot swarms and interpret our results in relation to the likely path that nature took to evolve complex sociality and task specialization.     

The Relative Decline in Women's Contribution to Agriculture with Intensification

This paper suggests why the intensification of agriculture is associated with a relative decline in women's participation in agriculture. The statistical evidence described here is consistent with the theory that women contribute relatively less to agriculture when it becomes intensive because their domestic work and fertility have increased. It is also argued that most men may be able to contribute more to agriculture in societies cultivating intensively because hunting, warfare, and trade are not so likely to pull them away from crop production [women's contribution to subsistence, agricultural intensification, time allocation, fertility, cross-cultural]     

Subsistence hunting and conservation issues in the game reserve of Gile, Mozambique

Ethnozoological research was conducted to gather information on the hunting activities and their relevance for the subsistence of local people in 8 villages around the game reserve of Gile, Mozambique. Two series of data were gathered by questionnaires to: (a) 510 householders from eight villages located in the outskirts of the Reserve; (b) 10 hunters from the village of Gile, the main centre of the study area. Several hunting techniques were recorded: spears, nets, traps (including gin-traps) and wildfires, while the use of guns did not appear relevant. The importance of subsistence hunting for local people was underlined by the high percentage of respondents who declared that they usually conduct this activity and sell bushmeat. The proportion of hunters per village was related to the village size but not to its geographical location of villages and the household composition. A positive relationship existed between the proportion of hunters, crop production and fishing activities, indicating that hunting is part of an integrated system of subsistence activities. Most animals harvested were mammals (89.5%, of which 46.7% were ungulates) and most were captured within the Reserve (96%). A higher percentage of animals was sold (56%), representing a relevant income source for the villagers. Small animals were mainly captured by traps during solitary hunting, medium-sized animals in collective net hunting; larger prey were captured by gin-traps adopted by both solitary and collective hunting. In the diet of the local people wild animals represented a higher protein source than domestic animals.     

The influence of food presentation on the behavior of small cats in confined environments

Captive small felids frequently pace repetitively and/or spend large amounts of time inactive. Presenting a fishing cat with live-fish resulted in more activity (60% less sleeping), increased behavioral diversity, including previously unobserved hunting behaviors, and greater enclosure utilization. Effects persisted for at least 48 h after presentation of live fish, and up to 8 days. In a second study, four leopard cats were fed: (1) once per day, (2) four times per day and, (3) four times per day with food hidden in small piles of brush. Multiple feedings of hidden food increased daily exploratory behavior from 5.5% to over 14%, and increased the diversity of behaviors observed. It also reduced the total duration, and bout length of stereotyped pacing. These studies suggest that providing food to small cats in a way that minimizes predictability of food availability, while maximizing the functional consequences of foraging behavior, can be an effective enrichment technique. These results are discussed in relation to two models of behavioral motivation, one that focuses on the issue of behavioral needs, and the other that emphasizes the importance of information acquisition. © 1993 Wiley-Liss, Inc.     

Teams in animal societies

We review the existence of teams in animal societies. Teamshave previously been dismissed in all but a tiny minority ofinsect societies. "Team" is a term not generally used in studiesof vertebrates. We propose a new rigorous definition of a teamthat may be applied to both vertebrate and invertebrate societies.We reconsider what it means to work as a team or group andsuggest that there are many more teams in insect societies than previously thought. A team task requires different subtasksto be performed concurrently for successful completion. Thereis a division of labor within a team. Contrary to previousreviews of teams in social insects, we do not constrain teamsto consist of members of different castes and argue that teammembers may be interchangeable. Consequently, we suggest thata team is simply the set of individuals that performs a teamtask. We contrast teams with groups and suggest that a grouptask requires the simultaneous performance and cooperationof two or more individuals for successful completion. In agroup, there is no division of labor—each individual performs the same task. We also contrast vertebrate and invertebrateteams and find that vertebrate teams tend to be associatedwith hunting and are based on individual recognition. Invertebrateteams occur in societies characterized by a great deal of redundancy,and we predict that teams in insect societies are more likelyto be found in large polymorphic ("complex") societies thanin small monomorphic ("simple") societies.