Biology subjects

Revathe, T.

Publications and source records attributed to Revathe, T..

4 recordsLinked to original sources

bioRxiv2025

Chimpanzee culture beyond the conspicuous: Evidence for broad-scale observational social learning in wild individuals

Wild chimpanzees possess diverse cultural repertoires, representing the richest example of non-human animal cultures. However, traditional methods, which investigate culture at the group level, have likely underestimated the full extent of chimpanzee cultural repertoires. In particular, the cultural relevance of everyday behaviors has remained largely unexplored. Here, we investigated evidence for social transmission of everyday behaviors to assess the breadth of individuals cultural repertoires in a population of wild eastern chimpanzees (Pan troglodytes schweinfurthii). First, we validated whether peering (i.e. close-range observation of a conspecific) serves as an indicator of social (i.e., cultural) learning. We then examined the contexts in which chimpanzees engage in peering to determine the range of behaviors that may be culturally transmitted. Finally, we explored potential motivations and additional functions of peering behavior. Our results indicate that chimpanzees use peering for targeted social information seeking in learning-intensive contexts. Peering rate was highest during immaturity, for complex or rare food items, and when observing older, more experienced conspecifics. Overall, wild chimpanzees peered at a wide range of everyday skills, such as feeding and grooming, and directed peering towards various conspecifics from an early age. We found no evidence supporting peering as a begging or submissive "gesture", but our findings indicate that it may function as a signal to initiate affinitive interactions. Our findings suggest that wild chimpanzees use peering to learn a broad variety of skills, thereby highlighting unrecognized cultural potential in everyday skills. Furthermore, our findings suggest that peering may have multiple functions and underlying motivations.

animal behavior and cognition↗

bioRxiv2025

Eight years of social and asocial learning synergistically shape orangutan diet profiles

Cultural learning permeates human skill and knowledge acquisition. To understand its significance for nonhuman animals, we must examine how social learning shapes the development of broad behavioral repertoires, and operates alongside other forms of learning. We analyzed nearly seven thousand records of behavioral indicators of social and individual learning across wild orangutans eight-year dependency period to assess their combined effects on ecological competence relevant for post-independence survival. Social learning was five times more frequent than individual learning and influenced subsequent learning for hours. Immatures varied substantially in their learning propensities and those with heightened social and individual learning propensities developed the most expansive diet profiles at independence. Our findings advance the science of cultural evolution by showing that multi-year social and individual learning synergistically shape great apes broad ecological competence.

animal behavior and cognition↗

bioRxiv2025

Young Asian elephant calves show differentiated social relationships with conspecifics

Social relationships may increase longevity and reproductive success of individuals, thereby providing crucial benefits in social species. Adults of many social species have differentiated social relationships; however, when and how these relationships form and are maintained are often not understood. We studied spatial and behavioural interactions between young calves ([≤]6 months old) and conspecific females ([≥]5 years old) to understand social ontogeny in a wild Asian elephant (Elephas maximus) population in Nagarahole and Bandipur National Parks, southern India. We found that elephant groups with calves comprised females - mother and escort, who provided active care, and females who did not provide overt, active care - other females. Escorts, apart from coordinating their movement with the calf, provided allomaternal care by initiating positive and helpful interactions with the calf. Other females rarely initiated interactions, which were usually negative, towards calves. Primarily calves, rather than conspecific females, initiated and terminated proximity contacts and behavioural interactions. Calves were near and interacted similarly with their mothers and escorts, under feeding, resting, and social contexts, and almost never interacted with other females. Similarly, we found remarkable similarities between mothers and escorts in their behaviours towards calves, with the primary difference being that escorts did not provide milk. Our results suggest that calves begin to form differentiated social relationships from a young age. The presence of calves and their interactions with escorts might result from existing close social relationship between mothers and escorts or may establish new relationships. Allomaternal care may also reinforce relationship differentiation in such social species. As calf-escort interactions involved behaviours that may potentially be helpful in protection and feeding skill acquisition, the development and survival of calves may be affected by the presence of, and interactions, with allomothers. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=197 HEIGHT=200 SRC="FIGDIR/small/650831v2_ufig1.gif" ALT="Figure 1"> View larger version (83K): org.highwire.dtl.DTLVardef@1564ccdorg.highwire.dtl.DTLVardef@cc276aorg.highwire.dtl.DTLVardef@12fc57corg.highwire.dtl.DTLVardef@14e7a8e_HPS_FORMAT_FIGEXP M_FIG C_FIG We studied spatial and behavioural interactions between young calves ([≤]6 months old) and conspecific females to understand social ontogeny in a wild Asian elephant population. We found differentiated relationships between calves and conspecifics even at a young age. Escorts, who showed coordinated movement with calves, engaged in other positive interactions with calves, with remarkable similarity to the mothers, whereas other females rarely initiated such interactions. Escorts are thus allomothers in the Kabini elephant population. Calves, rather than conspecifics, initiated and terminated most of the proximity and behavioural interactions and were thus precocial in forming new relationships.

animal behavior and cognition↗

bioRxiv2024

Sumatran orangutan mothers differ in the extent and trajectory of their expression of maternal behaviour

Mothers play a crucial role in the early development and survival of mammalian offspring, and differences in maternal care may differentially affect offsprings development. Whereas previous research has primarily focused on biological and socioecological factors to understand population-level variation in maternal behaviour, the individual as a source of variation remains understudied. We investigated between-individual variation in the average expression of, and plasticity in, six maternal behaviours in Sumatran orangutans, using 15 years of behavioural data. We found that mothers differed substantially in the average expression of four maternal behaviours, even after controlling for socioecological conditions, biological state characteristics, and the offsprings influence on these behaviours. Furthermore, not controlling for these confounding effects exaggerated or masked between-individual variation. Mothers also substantially differed in how they adjusted three of the maternal behaviours during offspring development, meaning that mothers differed in behavioural plasticity. Our results suggest that Sumatran orangutan mothers are constrained in the average expression of maternal behaviours and their plastic responses, potentially resulting in consistent differences among mothers, otherwise called maternal personality. Our findings highlight that individual variation around the population mean in maternal behaviour is more than noise and presents opportunities to study novel evolutionary processes that shape maternal behaviour.

animal behavior and cognition↗