Food Calls Research Articles

Chicks produce consonant, sometimes jazzy, sounds.

Several animal species prefer consonant over dissonant sounds, a building block of musical scales and harmony. Could consonance and dissonance be linked, beyond music, to the emotional valence of vocalizations? We extracted the fundamental frequency from calls of young chickens with either positive or negative emotional valence, i.e. contact, brood and food calls. For each call, we calculated the frequency ratio between the maximum and the minimum values of the fundamental frequency, and we investigated which frequency ratios occurred with higher probability. We found that, for all call types, the most frequent ratios matched perfect consonance, like an arpeggio in pop music. These music-like intervals, based on the auditory frequency resolution of chicks, cannot be miscategorized into contiguous dissonant intervals. When we analysed frequency ratio distributions at a finer-grained level, we found some dissonant ratios in the contact calls produced during distress only, thus sounding a bit jazzy. Complementing the empirical data, our computational simulations suggest that physiological constraints can only partly explain both consonances and dissonances in chicks' phonation. Our data add to the mounting evidence that the building blocks of human musical traits can be found in several species, even phylogenetically distant from us.

Weight method for determination of soluble β-glucans in barley grain

Background. Barley (Hordeum vulgare L.) is an important source of nutrients, such as starch, protein, and various dietary fibers. β-Glucans are soluble fibers found in high amounts in oat and barley grain, so they are becoming increasingly interesting due to their numerous functional and bioactive properties. The increased interest in β-glucans as a dietary supplement and a functional component of food calls for a convenient, inexpensive and affordable method for quantitative determination of these compounds.Materials and methods. An overview is given on the existing techniques for determining and isolating β-glucans in cereals: IR spectroscopy, enzymatic, colorimetric, and alkaline-enzymatic methods. Their advantages and disadvantages are shown. The disadvantages of the methods considered include high costs of reagents and equipment, duration of performance, and labor intensity.Results. This study promotes the weight method for isolation and quantitative determination of β-glucans in the grain of covered and naked barley. It is based on the modified alkaline method adapted to barley; we developed it earlier for oat grain. The amount of β-glucans in the grain of the studied barley accessions ranged from 4.12±0.23% to 5.34 ± 0.31% for naked cultivars, and from 3.57 ± 0.18% to 4.29 ± 0.32% for covered ones.Conclusion. Based on the conducted research, optimal conditions for the isolation and quantitative determination of β-glucans from barley grain were selected: centrifugation modes, temperature and extraction ratio, concentration of compounds, precipitation and drying procedures. The main advantage of the described method is its accessibility and practical applicability when conducting mass analysis, including studying a collection of cereal crops.

Do chimpanzee food calls bias listeners toward novel items?

Social learning is beneficial in almost every domain of a social animal's life, but it is particularly important in the context of predation and foraging. In both contexts, social animals tend to produce acoustically distinct vocalizations, alarms, and food calls, which have remained somewhat of an evolutionary conundrum as they appear to be costly for the signaller. Here, we investigated the hypothesis that food calls function to direct others toward novel food items, using a playback experiment on a group of chimpanzees. We showed chimpanzees novel (plausibly edible) items while simultaneously playing either conspecific food calls or acoustically similar greeting calls as a control. We found that individuals responded by staying longer near items previously associated with food calls even in the absence of these vocalizations, and peered more at these items compared with the control items, provided no conspecifics were nearby. We also found that once chimpanzees had access to both item types, they interacted more with the one previously associated with food calls than the control items. However, we found no evidence of social learning per se. Given these effects, we propose that food calls may gate and thus facilitate social learning by directing listeners' attention to new feeding opportunities, which if integrated with additional cues could ultimately lead to new food preferences within social groups.

The Everyday Economy and the Right to Food

AbstractThis article makes the case for incorporating the right to food into notions of the everyday economy in the UK. Beyond the important entitlement to sufficient safe, nutritious and affordable food, the right to food calls for structural change in the current food system and the empowerment of citizens in the everyday production, procurement and consumption of food. We consider the role of reproduction and consumption of food in everyday settings of the household, workplace and community, suggesting that considerations of time combine with questions of earnings and income in addressing the UK's deepening crisis in food security.

The Evolution of Food Calls: Vocal Behaviour of Sooty Mangabeys in the Presence of Food.

The two main theories of food-associated calls in animals propose functions either in cooperative recruitment or competitive spacing. However, not all social animals produce food calls and it is largely unclear under what circumstances this call type evolves. Sooty mangabeys (Cercocebus atys) do not have food calls, but they frequently produce grunts during foraging, their most common vocalisation. We found that grunt rates were significantly higher when subjects were foraging in the group’s periphery and with small audiences, in line with the cooperative recruitment hypothesis. In a subsequent field experiment we presented highly desired food items and found that discovering individuals called, unless harassed by competitors, but that the calls never attracted others, confirming that the grunts do not convey any information referential to food. Our data thus suggest that the evolution of cooperative food calling is a two-step process, starting with increased motivation to vocalise in the feeding context, followed by the evolution of acoustic variants derived from context-general contact calls. This evolutionary transition may only occur in species that feed on clumped, high-quality resources where social feeding is competitive, a condition not met in sooty mangabeys.

Bonobos assign meaning to food calls based on caller food preferences.

Human communication relies heavily on pragmatic competence. Speech utterances are often ambiguous requiring listeners to use interaction history, shared knowledge, presumed intention and other contextual variables to make inferences about a speaker’s meaning. To probe the evolutionary origins of pragmatic competence we tested whether bonobos (Pan paniscus) can make inferences about the type of food available from listening to other group members’ food calls. We trained two group members to either prefer blue or pink chow and demonstrated these preferences to observers. A third group member served as an untrained control. In playback experiments, we broadcast the food calls of a trained demonstrator and the untrained group member to investigate whether subjects were able to infer which coloured chow was most likely available, based on the callers’ trained food preferences or lack thereof. As predicted, when hearing the untrained group member’s calls, subjects did not exhibit a bias, whereas they responded with a significant foraging bias when hearing a trained group member’s calls. These findings suggest that bonobos may take into account the idiosyncratic food preferences of others, although subjects probably differed in what they remembered.

Male chimpanzees communicate to mediate competition and cooperation during feeding

An ongoing debate in animal behaviour research is whether food calls function to cooperatively inform others or provide the caller with competitive advantages. When feeding, chimpanzees, Pan troglodytes, produce two types of call: context-specific, close-range ‘rough grunts’ and context-general, long-range ‘pant hoots’. We investigated this dual signalling behaviour by wild male chimpanzees that were either actively joining others or passively being joined in food trees, considering the effects of the audience composition and the type of food encountered. For arriving individuals, we found that pant hoot production was best explained by the absence of socially important individuals (i.e. social bond partners and/or high-ranking males), suggesting that callers were cooperatively informing them about food availability, probably to strengthen social relationships. In contrast, rough grunts were mostly produced by low-ranking individuals, suggesting they were part of competitive interactions to avoid aggression. For individuals already in a tree, we found that both rough grunt and pant hoot production were most common in low-ranking individuals reacting to the arrival of high-ranking males and there was no significant effect of the presence, or absence, of social bond partners. We discuss these patterns and conclude that, when chimpanzees enter a food tree, their vocal behaviour functions to mediate both cooperative and competitive interactions.

Trade-offs between vocal accommodation and individual recognisability in common marmoset vocalizations

Recent studies find increasing evidence for vocal accommodation in nonhuman primates, indicating that this form of vocal learning is more prevalent than previously thought. Convergent vocal accommodation (i.e. becoming more similar to partners) indicates social closeness. At the same time, however, becoming too similar may compromise individual recognisability. This is especially problematic if individual recognisability is an important part of the call function, like in long-distance contact calls. In contrast, in calls with a different function, the trade-off between signalling social closeness and individual recognisability might be less severe. We therefore hypothesized that the extent and consequences of accommodation depend on the function of a given call, and expected (1) more accommodation in calls for which individual identity is less crucial and (2) that individual identity is less compromised in calls that serve mainly to transmit identity compared to calls where individual recognisability is less important. We quantified vocal accommodation in three call types over the process of pair formation in common marmoset monkeys (Callithrix jacchus, n = 20). These three call types have different functions and vary with the degree to which they refer to individual identity of the caller. In accordance with our predictions, we found that animals converged most in close contact calls (trill calls), but less in calls where individual identity is more essential (phee- and food calls). In two out of three call types, the amount of accommodation was predicted by the initial vocal distance. Moreover, accommodation led to a drop in statistical individual recognisability in trill calls, but not in phee calls and food calls. Overall, our study shows that patterns of vocal accommodation vary between call types with different functions, suggestive of trade-offs between signalling social closeness and individual recognisability in marmoset vocalizations.

Food calls enhance visual discrimination learning in chimpanzees (Pan troglodytes verus).

Social learning is of universal importance to animal life, and communication is likely to foster it. How do animals recognize when others produce actions that lead to relevant new information? To address this, we exposed 4 chimpanzees to an arbitrary learning task, a 2-choice visual discrimination paradigm presented on a touch screen that led to food reward. In each trial, images were paired with 1 of 4 acoustic treatments: (a) relevant or (b) irrelevant chimpanzee calls ("rough grunts" to food; "pant grunts" to a dominant conspecific), (c) a mechanical noise (hammer knocking sounds) and (d) silence. As we were interested in the effect of food calls on learning speed as compared to control stimuli, each chimpanzee was tested with the food call treatment, and 1 of the 3 control stimuli (either the pant grunt, mechanical noise, or silence condition). We found that learning was significantly enhanced in the contextually correct "rough grunt" condition, suggesting that food calls may play a role in the cultural transmission of food preferences, by priming individuals about a learning opportunity. We discuss these findings and propose that, at least in chimpanzees, the enhancing effect of these vocalizations may be related to the way they affect receivers' motivational/emotional and/or attentional systems. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Chimpanzees combine pant hoots with food calls into larger structures

A growing body of observational and experimental data in nonhuman primates has highlighted the presence of rudimentary call combinations within the vocal communication system of monkeys. Such evidence suggests the ability to combine meaning-bearing units into larger structures, a key feature of language also known as syntax, could have its origins rooted within the primate lineage. However, the evolutionary progression of this trait remains ambiguous as evidence for similar combinations in great apes, our closest-living relatives, is sparse and incomplete. In this study, we aimed to bridge this gap by analysing the combinatorial properties of the pant hoot–food call combination in our closest-living relative, the chimpanzee, Pan troglodytes . To systematically investigate the syntactic-like potential of this structure, we adopted three levels of analysis. First, we applied collocation analyses, methods traditionally used in language sciences, to confirm the combination of pant hoots with food calls was not a random co-occurrence, but instead a consistently produced structure. Second, using acoustic analyses, we confirmed pant hoots and food calls comprising the combination were acoustically indistinguishable from the same calls produced in isolation, indicating the pant hoot–food call combination is composed of individually occurring meaning-bearing units, a key criterion of linguistic syntax. Finally, we investigated the context-specific nature of this structure, demonstrating that the call combination was more likely to be produced when feeding on larger patches and when a high-ranking individual joined the feeding party. Together our results converge to provide support for the systematic combination of calls in chimpanzees. We highlight that playback experiments are vital to robustly disentangle both the function this combination might serve and the similarities with combinations of meaning-bearing units (i.e. syntax) in language. • Chimpanzees combine pant hoots with food calls into larger nonrandom structures. • Calls in combinations are acoustically similar to individual ones. • They occur when feeding on large patches and when high-ranked individuals join. • Chimpanzees may combine calls to convey information on both ID and context.

Absence of specific individuals and high food abundance elicit food calls in wild western gorillas

Absence of specific individuals and high food abundance elicit food calls in wild western gorillas

Trash, tasty and healthy: the red-back agouti (Dasyprocta iacki) feed on leftovers from blonde capuchins (Sapajus flavius)

In primate-non-primate commensalism, food is often the benefit. Here we report commensalism between the Endangered blonde capuchins (Sapajus flavius) and the newly discovered red-back agoutis (Dasyprocta iacki). We conducted the study in an Atlantic forest fragment in Northeast Brazil between September 2017 and August 2018. In three of those months, we observed 15 events of commensalism where the agoutis were feeding on leftover palm fruits from the blonde capuchins. We suspect that the red-back agoutis in the study area could be consuming more palm oil fruits when compared to agoutis inhabiting areas without the blonde capuchins. Comparison of the diet of agouti populations in such areas may help to test such a hypothesis. Also, due to the potential influence of the observer’s presence on the behaviour of the animals, further studies comparing sites through camera trapping may be another effective approach to test the hypothesis. Blonde capuchin food calls and the noises of fruits falling during the feeding bouts may serve as clues to attract the agoutis to consume the leftover palm fruits. Future studies using playback (or sound trapping associated with camera trapping) would be needed to confirm whether red-back agoutis are eavesdropping on blonde capuchins feeding noises to optimise their food and energy intakes.

Tameness correlates with domestication related traits in a Red Junglefowl intercross

Early animal domestication may have been driven by selection on tameness. Selection on only tameness can bring about correlated selection responses in other traits, not intentionally selected upon, which may be one cause of the domesticated phenotype. We predicted that genetically reduced fear towards humans in Red Junglefowl, ancestors of domesticated chickens, would be correlated to other traits included in the domesticated phenotype. Fear level was determined by a standardised behaviour test, where the reaction towards an approaching human was recorded. We first selected birds for eight generations for either high or low fear levels in this test, to create two divergent selection lines. An F3 intercross, with birds from the eighth generation as parentals, was generated to study correlations between fear‐of‐human scores and other unselected phenotypes, possibly caused by pleiotropy or linkage. Low fear‐of‐human scores were associated with higher body weight and growth rates, and with increased activity in an open field test, indicating less general fearfulness. In females, low fear‐of‐human scores were also associated with more efficient fear habituation and in males with an increased tendency to emit food calls in a mirror test, indicating increased social dominance. Low fear‐of‐human scores were also associated with smaller brain relative to body weight, and with larger cerebrum relative to total brain weight in females. All these effects are in line with the changes observed in domesticated chickens compared to their ancestors, and we conclude that tameness may have been a driving factor underlying some aspects of the domesticated phenotype.

The relationship between food calling and agonistic behaviour in wild chimpanzees

A number of social animals produce food-associated calls, which have been interpreted as informative and referential about the quality or quantity of food accessed by the caller. In chimpanzees, however, some behavioural patterns have remained unexplained by this model, suggesting that food-associated calls have a more generalized social function beyond attracting others to food, such as promoting tolerance between co-feeding individuals. In this study, we investigated how wild chimpanzees (Pan troglodytes schweinfurthii) of Budongo Forest, Uganda, use food associated-calls in situations when social tolerance is low, i.e., during agonistic interactions. We found a positive relationship between food calling and agonistic behaviours during a feeding event, independent of the number of males on the feeding patch. Moreover, food calling followed rather than preceded agonistic interactions, suggesting that aggression can trigger food call production. These results support the view that chimpanzee food-associated calls can act as social tools mediating competitive or aggressive interactions.

Spectral entropy of early-life distress calls as an iceberg indicator of chicken welfare.

Chicks (Gallus gallus domesticus) make a repetitive, high energy ‘distress’ call when stressed. Distress calls are a catch-all response to a range of environmental stressors, and elicit food calling and brooding from hens. Pharmacological and behavioural laboratory studies link expression of this call with negative affective state. As such, there is an a priori expectation that distress calls on farms indicate not only physical, but emotional welfare. Using whole-house recordings on 12 commercial broiler flocks (n = 25 090–26 510/flock), we show that early life (day 1–4 of placement) distress call rate can be simply and linearly estimated using a single acoustic parameter: spectral entropy. After filtering to remove low-frequency machinery noise, spectral entropy per minute of recording had a correlation of −0.88 with a manual distress call count. In videos collected on days 1–3, age-specific behavioural correlates of distress calling were identified: calling was prevalent (spectral entropy low) when foraging/drinking were high on day 1, but when chicks exhibited thermoregulatory behaviours or were behaviourally asynchronous thereafter. Crucially, spectral entropy was predictive of important commercial and welfare-relevant measures: low median daily spectral entropy predicted low weight gain and high mortality, not only into the next day, but towards the end of production. Further research is required to identify what triggers, and thus could alleviate, distress calling in broiler chicks. However, within the field of precision livestock farming, this work shows the potential for simple descriptors of the overall acoustic environment to be a novel, tractable and real-time ‘iceberg indicator’ of current and future welfare.

Mapping Food Insecurity-Related 2-1-1 Calls in a 10-County Area of Central Texas by Zip Code: Exploring the Role of Geographic Food Access, Urbanicity and Demographic Indicators.

Food insecurity is a public health issue that affects 12% of Americans. Individuals living in food insecure households are more likely to suffer from conditions such as undernutrition, obesity and chronic diseases. Food insecurity has been linked to limited geographic access to food; however, past studies have used limited measures of access which do not fully capture the nuances of community context. The purpose of this study was to explore the association between food insecurity and geographic food access by level of urbanicity. 2-1-1 calls made in 2018 in Central Texas were classified as food needs versus non-food needs. Supermarket and convenience stores were mapped using ArcGIS. Geographic food access was operationalized as the presence of supermarkets and convenience stores: within the zip code; only in neighboring zip codes; and not located within or in neighboring zip codes. Descriptive statistics and binomial logistic regression were used to examine associations between geographic access and 2-1-1 food calls, stratified by level of urbanicity. 11% of the 2-1-1 calls made in 2018 (N = 55,405) were regarding food needs. Results showed that peri-urban and rural callers living in zip codes that only had supermarkets in neighboring zip codes had greater odds of calling about food needs compared to those that had supermarkets within the zip code. These findings indicate that geographic food access is associated with food insecurity, but this relationship varies by urbanicity. Thus, the development of food insecurity mitigation programs in peri-urban and rural areas is needed.

Resistance and Renewal: How Native Food Sovereignty Movements Should Guide Human Rights and Social Work

The historical use of food as a means of social control has led to stark health inequities in Native communities throughout the USA, and many federal structures and policies meant to support Native well-being and self-determination serve rather as tools of ongoing colonization and marginalization. Addressing these inequities and supporting Indigenous communities in the fulfillment of their right to adequate, culturally acceptable food calls for our critical consideration of how and when a rights-based approach to social work might be effective and ethically sound. Given Indigenous peoples’ disproportionate vulnerability at the intersection of environmental justice and food justice, Native leadership regarding these issues must be elevated in local, national, and global conversations about climate change and human rights fulfillment.

Food calling in wild ravens (Corvus corax) revisited: Who is addressed?

AbstractNumerous birds and mammals use vocal signals to advertise feeding opportunities but often such signals vary with individual and contextual factors. Non‐breeding ravens call at food that is difficult to access, resulting in the attraction of nearby conspecifics. Although callers may benefit from group formation in various ways, we recently found substantial individual variation in food calling. We here explored whether this variation can be partly explained by the social dynamics in raven foraging groups, together with already known effects of age class and sex. Specifically, we expected ravens to respond to the presence or absence of affiliates that could act as cooperative partners in the forthcoming feeding event, that is they should call when other ravens were present but they themselves were alone rather than when they were also in company of an affiliation partner. We observed the vocal behaviour of individually marked wild ravens and, simultaneously, categorized their affiliative behaviour with other ravens in the minutes before experimentally controlled feedings. In line with our prediction, individuals were less likely to produce food‐associated calls when they were in close contact with an affiliation partner prior to feeding as compared to when they were alone. Furthermore, sex and age class influenced food calling as females called more often than males and younger birds called more often than adult ravens. In conclusion, these results suggest that ravens attempt to find support from a particular cooperative partner by broadly advertise feeding opportunities via food‐associated calls, especially when they have low chances in contest competition due to their age and sex. These findings lend further support to the assumption of raven flocks being structured by social relationships and individual birds flexibly controlling their vocal signalling according to the current flock composition.

Household food security measurement: a critical review from a gender perspective

ABSTRACT Despite the growing international interest in addressing the relationship between gender inequalities and food insecurity – as well as the valuable feminist contributions of family studies – development and humanitarian actors still use gender-insensitive household food security measurements in developing countries. Such measurements rest on unrealistic assumptions about gender relations within the household; thus, their use in development projects risks masking gender disparities and rendering invisible serious intra-household food access inequalities. To demonstrate the problems resulting from these presumed gender-neutral measurements, this paper examines a set of metrics that influence food security policy and reveals gender biases in their methodological design and use. The paper concludes by offering simple methodological guidelines for mainstreaming gender analysis in household food security measurement processes and calls for a deeper analysis based on a feminist application of the capabilities approach.

The use of infrared thermography to investigate emotions in common marmosets

Measuring body surface temperature changes with infrared thermography has recently been put forward as a non-invasive alternative measure of physiological correlates of emotional reactions. In particular, the nasal region seems to be highly sensitive to emotional reactions. Several studies suggest that nasal temperature is negatively correlated with the level of arousal in humans and other primates, but some studies provide inconsistent results. Our goal was to establish the use of infrared thermography to quantify emotional reactions in common marmosets (Callithrix jacchus), with a focus on the nasal region. To do so we exposed 17 common marmosets to a set of positive, negative and control stimuli (positive: preferred food, playback of food calls; negative: playback of aggressive vocalizations, teasing; control: no stimulus). We compared nasal temperature before and after the stimuli and expected that highly aroused emotional states would lead to a drop in nasal temperature. To validate the thermography measure, we coded piloerection of the tail as an independent measure of arousal and expected a negative correlation between the two measures. Finally, we coded physical activity to exclude its potential confounding impact on nasal temperature. Our results show that all predictions were met: the animals showed a strong decrease in nasal temperature after the presentation of negative arousing stimuli (teasing, playback of aggressive vocalizations). Furthermore, these changes in nasal temperature were correlated with piloerection of the tail and could not be explained by changes in physical activity. In the positive and the control conditions, we found systematic sex differences: in males, the preferred food, the playbacks of food calls, as well as the control stimulus led to an increase in nasal temperature, whereas in females the temperature remained stable (preferred food, control) or decreased (playback of food calls). Based on naturalistic observations that document higher food motivation and competition among female marmosets, as well as stronger reactions to separation from group members in male marmosets, these sex differences corroborate a negative correlation between arousal and nasal temperature. Overall, our results support that measuring nasal temperature by infrared thermography is a promising method to quantify emotional arousal in common marmosets in a fully non-invasive and highly objective way.