scholarly journals Bonobos voluntarily hand food to others but not toys or tools

2018 ◽  
Vol 285 (1886) ◽  
pp. 20181536 ◽  
Author(s):  
Christopher Krupenye ◽  
Jingzhi Tan ◽  
Brian Hare

A key feature of human prosociality is direct transfers , the most active form of sharing in which donors voluntarily hand over resources in their possession . Direct transfers buffer hunter-gatherers against foraging shortfalls. The emergence and elaboration of this behaviour thus likely played a key role in human evolution by promoting cooperative interdependence and ensuring that humans' growing energetic needs (e.g. for increasing brain size) were more reliably met. According to the strong prosociality hypothesis , among great apes only humans exhibit sufficiently strong prosocial motivations to directly transfer food. The versatile prosociality hypothesis suggests instead that while other apes may make transfers in constrained settings, only humans share flexibly across food and non-food contexts. In controlled experiments, chimpanzees typically transfer objects but not food, supporting both hypotheses. In this paper, we show in two experiments that bonobos directly transfer food but not non-food items. These findings show that, in some contexts, bonobos exhibit a human-like motivation for direct food transfer. However, humans share across a far wider range of contexts, lending support to the versatile prosociality hypothesis. Our species' unusual prosocial flexibility is likely built on a prosocial foundation we share through common descent with the other apes.

2019 ◽  
pp. 154-180
Author(s):  
Riane Eisler

Mobile foragers—also called nomadic hunter-gatherers—constitute the oldest form of human social organization, predating by far the agricultural revolution of about 10,000 years ago as well as the rise of pastoralists, tribal horticulturalists, chiefdoms, kingdoms, and ancient states. In the debates about the nature of human nature—whether we are more inclined toward war or peace, selfishness or altruism—nomadic forager societies are regularly evoked to draw inferences about human existence “in a state of nature” before the development of civilization. Studies of nomadic forager band societies suggest that humanity’s ancient orientation actually was toward partnership and peace rather than domination and war over the many millennia of human evolution. The main take-home lesson from a careful study of nomadic forager partnership societies—re-enforced by archeological studies, the recent Nordic experience, and other evidence—is that humans are capable of living in egalitarian social systems where neither sex dominates the other, where violence is minimized, and where prosocial cooperation and caring typify social life. This image is not a utopian fantasy but rather a set of potentials, if not inclinations, stemming from our evolutionary heritage. Since partnership behaviors have been essential to survival for the millions of years that humans and their ancestors foraged for a living, the study of archaeology and nomadic forager societies raises an intriguing possibility. Given the long-standing evolutionary legacy of partnership, human minds and dispositions may be especially inclined toward the empathic, caring, egalitarian, prosocial, cooperative behaviors.


2020 ◽  
Vol 60 (3) ◽  
pp. 765-781 ◽  
Author(s):  
Kristen Hawkes

Abstract When Fisher, Williams, and Hamilton laid the foundations of evolutionary life history theory, they recognized elements of what became a grandmother hypothesis to explain the evolution of human postmenopausal longevity. Subsequent study of modern hunter-gatherers, great apes, and the wider mammalian radiation has revealed strong regularities in development and behavior that show additional unexpected consequences that ancestral grandmothering likely had on human evolution, challenging the hypothesis that ancestral males propelled the evolution of our radiation by hunting to provision mates and offspring. Ancestral grandmothering has become a serious contender to explain not only the large fraction of post-fertile years women live and children’s prolonged maturation yet early weaning; it also promises to help account for the pair bonding that distinguishes humans from our closest living evolutionary cousins, the great apes (and most other mammals), the evolution of our big human brains, and our distinctive preoccupation with reputations, shared intentionality and persistent cultural learning that begins in infancy.


2011 ◽  
Vol 7 (6) ◽  
pp. 875-877 ◽  
Author(s):  
Sandra Mikolasch ◽  
Kurt Kotrschal ◽  
Christian Schloegl

Exclusion allows the detection of hidden food when confronted with the choice between an empty and a potentially baited food location. However, exclusion may be based on avoidance of the empty location without drawing inferences about the presence of the food in the baited location. So far, such inferences have been demonstrated in the great apes only: after seeing an experimenter eating one of two food types, which both had been hidden previously in two boxes, the apes were able to choose the box that still contained the other food type. African grey parrots are capable of exclusion, and we here assessed if they are capable of inference by exclusion. In our task, two different but equally preferred food items were hidden in full view of the birds under two opaque cups. Then, an experimenter secretly removed one food type and showed it to the bird. Similarly to the apes, one out of seven parrots significantly preferred the baited cup; control conditions rule out that its choice was based on associative learning or the use of olfactory cues. Thus, we conclude that—like the apes—some grey parrots are able to infer the location of a hidden food reward.


1987 ◽  
Vol 57 (01) ◽  
pp. 029-034 ◽  
Author(s):  
Göran Urdén ◽  
Joanna Chmielewska ◽  
Tomas Carlsson ◽  
Björn Wiman

SummaryPolyclonal antibodies have been raised against the inhibitor moiety in the purified complex between tissue plasminogen activator and its fast inhibitor (PA-inhibitor) in human plasma/ serum. A radioimmunoassay for quantitation of PA-inhibitor antigen was developed. The polyclonal antiserum and a previously described monoclonal antibody against the PA-inhibitor (14) have been used to study the immunological relationship between PA-inhibitors from plasma, serum, platelets, placenta extract and conditioned media from Hep G2 and HT 1080 cells. It was demonstrated that the ratio between PA-inhibitor activity and antigen varied considerably between the different sources. In the plasma samples studied, similar activity and antigen concentrations were found, suggesting that the PA-inhibitor in these samples mainly was in an active form. On the other hand the other sources seemed to contain variable amounts of inactive PA-inhibitor forms. Immunoadsorption experiments revealed that the PA-inhibitor (activity and antigen) from all the sources were specifically bound to the insolubilized antibodies (polyclonal and monoclonal). In no case, however, could active PA-inhibitor be eluted from the immunoadsorption columns. Also the competitive radioimmunoassays suggested that the PA-inhibitors from the different sources studied, were closely immunologically related.


1992 ◽  
Vol 57 (11) ◽  
pp. 2302-2308
Author(s):  
Karel Mocek ◽  
Erich Lippert ◽  
Emerich Erdös

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.


Author(s):  
Angela M. Kurth ◽  
Darcia Narvaez

Like every animal, human offspring evolved to fit into their communities, but social fittedness for mammals requires a supportive early nest that fosters socio-emotional intelligence, self-regulation, and sympathy. Within a supportive environment, children naturally develop orientations that facilitate prosocial behaviours within the community. We use the evolved developmental niche (EDN), apparent in 95% of human history as small-band hunter-gatherers, for a baseline representative of human evolution. In these societies, children grow into cooperative, agile moral actors. We compare the EDN with five modern approaches to young child group care and make suggestions to early caregivers on how to provide, in the modern world, what children evolved to need.


2007 ◽  
Vol 85 (9) ◽  
pp. 985-993 ◽  
Author(s):  
E.E. Fraser ◽  
M.B. Fenton

Eating behaviour can vary with age, experience, and gender, as well as food hardness. This variation can contribute to intraspecific dietary differences and may result in variable definitions of optimal foraging and decreased intraspecific competition. We quantified feeding behaviour of insectivorous bats eating hard and soft mealworm-based food items based on the bats’ ability to consume and manipulate food items, consumption time, chew frequency, and total chews to consume. Adult Myotis lucifugus (LeConte, 1831) were more successful at both consuming and manipulating mealworms and consumed mealworms more quickly, with greater chew frequency and in fewer chews, than did subadults. Adults chewed mealworm viscera more frequently than did subadults but showed no differences in the other variables. Adult Eptesicus fuscus (Beauvois, 1796) consumed mealworms more quickly and with fewer chews than did subadults but showed no differences in the other variables. There were no differences between adult and subadult E. fuscus when consuming mealworm viscera. Male and female M. lucifugus did not differ significantly when eating either mealworms or mealworm viscera. There was no change in subadult consumption time of mealworms over the summer. Age-based differences in eating abilities may play a role in defining optimal foraging and dietary composition in insectivorous bats.


1996 ◽  
Vol 37 (1) ◽  
pp. 125-129 ◽  
Author(s):  
William R. Leonard ◽  
Marcia L. Robertson ◽  
Leslie C. Aiello ◽  
Peter Wheeler

1994 ◽  
Vol 126 (3) ◽  
pp. 667-672 ◽  
Author(s):  
Ross T. Bell

AbstractIn Rhysodini the greatly enlarged mentum forms the entering edge as the beetle wedge-pushes its way through wood. The mandibles cannot bite either wood fibers or food items, but function as a cover for the other mouthparts. The palpi are completely retractile. Each maxilla bears two stylets, the galea and lacinia, and the ligula consists of two bilobed structures. These are apparently the sole feeding structures enabling the beetles to prey on the amoeboid stage of slime molds. The large internal cavity of the head is interpreted as a compromise between a greatly reduced head volume, resulting from reduced jaw musculature, and the need to retain the surface of a full-sized head as part of the wedge-pushing apparatus.


2004 ◽  
Vol 64 (2) ◽  
pp. 353-356 ◽  
Author(s):  
M. Van Sluys ◽  
V. M. Ferreira ◽  
C. F. D. Rocha

Information on the ecology of lizard species from the Brazilian Atlantic Forest is scarce and almost nothing is known about the ecology of lizards of the genus Enyalius. In this study, we provide information about some aspects of the natural history of E. brasiliensis from an area of Atlantic Forest in Ilha Grande, RJ. Enyalius brasiliensis (N = 15) feeds mainly on arthropods. The most frequent food items were insect larvae, orthopterans, and ants; in terms of volume, larvae and termites were the most important food items; ants and termites were the most numerous prey categories. Two females were reproductive (one had 10 and the other, five vitellogenic follicles); the smallest measured 92.4 mm in SVL. Seven lizards were found on forest leaf litter. The other microhabitats used were vines, fallen logs, branches, and a crevice on a slope.


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