Biology subjects

Haldar, E.

Publications and source records attributed to Haldar, E..

3 recordsLinked to original sources

bioRxiv2025

Subadult macaws (Ara glaucogularis) copy better than adults but are less likely to imitate in problem-solving tasks

Copying via imitation (replicating others bodily actions) or emulation (replicating others action goals) underpins the cultural transmission of social norms and technical skills in humans. In this study, we investigated whether blue-throated macaws (Ara glaucogularis) are capable of copying conspecifics using two problem-solving devices: door and plug. The door device could be solved by sliding a panel either UP or DOWN, while the plug device required removing a stopper via either a PUSH or PULL action. A control group (N=5), which received no demonstrations, consistently preferred a single solution for each device-- DOWN for door and PULL for plug. In the subsequent test, adult (N=5) and subadult (N=5) macaws from the test group observed demonstrators (N=2) performing the non-preferred action for each device. Significantly more test birds copied the demonstrated action (UP) for door, but not PUSH for plug, because the subadults were less likely to imitate the PUSH action than the adults. However, the subadults took significantly less time to approach and manipulate the devices than the adults. Overall, our study shows that macaws can copy conspecifics in problem-solving tasks, which facilitates information transfer and transmission of foraging techniques, a prerequisite for foraging culture to arise.

animal behavior and cognition↗

bioRxiv2025

Third-party imitation is not restricted to humans

Imitation of cultural practices is ubiquitous in humans and often involves faithful copying of intransitive (i.e., non-object directed) gestures and societal norms which play a crucial role in human cultural evolution. Apart from learning these directly from a tutor, humans often learn passively as third-party observers from the interactions of two or more individuals. Whether third-party imitation has evolved outside humans remains unknown. In the current study, we investigated whether undomesticated blue-throated macaws could imitate in a third-party setting. A naive test group (N=6) passively observed a conspecific demonstrator performing improbable intransitive actions in response to specific human gestural commands. Directly afterwards, the observer received the same gestural commands and performance-contingent rewards. An equally naive control group (N=5) was tested correspondingly, in the absence of third-party demonstrations. The test group learned more target actions (mean=4.16 versus mean=2.2) in response to the specific commands, significantly faster and performed them more accurately than the control group. The test group also spontaneously imitated some of the actions even before they received any gestural commands or rewards. Our findings show that third-party imitation, even for intransitive actions, exists outside humans, allowing for rapid adaption to group specific behaviours and possibly cultural conventions in parrots.

animal behavior and cognition↗

bioRxiv2024

Evolution of vocal production learning in parrots

Vocal production learning (VPL), the capacity to imitate sounds, is a crucial, but not exclusive component of human language. VPL is rare in animals but common in birds, where it evolved independently in songbirds, hummingbirds, and parrots. Parrots (Psittaciformes) learn new vocalizations throughout their lives and exhibit astonishing vocal flexibility and imitation capacity. They can copy allospecific sounds, e.g., human words and learn their associated meanings. Parrots, therefore, present an intriguing model to shed light on how VPL evolved and how it may relate to other language-relevant traits. How widely VPL is distributed across Psittaciformes and to what extent (qualitative) species differences exist, remains unknown. Here, we provide the first comprehensive overview of the phylogenetic distribution of (allospecific) VPL in this clade by conducting surveys of publicly available video footage. Out of the 398 currently recognized extant species, we found videos for 163, of which 136 showed evidence of VPL. Phylogenetic analyses suggest secondary losses and reacquisitions of VPL covarying with socioecological parameters (gregariousness), life-history (longevity), and morphological (body size) traits. This study provides the first insights into interspecific variation in vocal learning across all parrot species and reveals potential socio-ecological drivers of its evolution. SignificanceLittle is known about the selective forces that favor the evolution of vocal production learning (VPL), a rare trait in animals and a prerequisite for the evolution of human language. We provide the first insights into interspecific variation in VPL in the evolutionary history of parrots and uncover candidate evolutionary drivers. The current data suggest that the evolution of VPL within parrots has been highly dynamic, with multiple secondary losses and reacquisitions. Our model showed that VPL most likely was the ancestral state. Sociality, longevity and body size explain variation in VPL together with a highly uncertain effect of brain size. The findings may motivate comparative work in other taxa and contribute to research into the evolutionary origins of human language.

evolutionary biology↗