The ability of ravens (Corvus corax Linnaeus, 1758) to evaluate human behavior from a bystander perspective

• Main Author: Tomašić, Ana
• Other Authors: Bugnyar, Thomas, Tadić, Zoran
• Format: Master Thesis
• Language: English
• Published: Sveučilište u Zagrebu. Prirodoslovno-matematički fakultet. Biološki odsjek. 2021
• Subjects: animal cognition; third-party evaluation; kognicija životninja; indirektna recipročnost; gavran; PRIRODNE ZNANOSTI. Biologija; NATURAL SCIENCES. Biology; The Ravens; sami
• Online Access: https://zir.nsk.hr/islandora/object/pmf:10019; https://urn.nsk.hr/urn:nbn:hr:217:873086; https://repozitorij.unizg.hr/islandora/object/pmf:10019; https://repozitorij.unizg.hr/islandora/object/pmf:10019/datastream/PDF

Ravens (Corvus corax) have a complex social structure with various interaction between individuals. Predicting the behavior of others based on observation would be advantageous for future interactions. While previous studies showed that ravens can discriminate between human experimenters after direct interaction, I was interested to see if they would be able to do so when put in a bystander position. In this study, individual ravens could observe two experimenters engaging in the retrieval of their food previously cached or in the pilfering of the other’s cache. Two experimenters (pilferer or retriever versus a neutral person) offered food and each raven had the choice to take the food from one of them. Contrary to expectation, the ravens did not choose one experimenter significantly over the other. Yet, when comparing their choices made before and after the observation, I found a tendency to discriminate. Furthermore, the ravens changed their visual behavior (head turns) across the phase types of a trial, but not between the conditions. This study produced equivocal results, which might be caused by small sample size. Further investigation is needed to confirm whether ravens are capable to understand displayed human interaction and what behavioral actions ravens are paying attention to. Gavrani (Corvus corax) imaju složenu socijalnu strukturu u kojoj su jedinke izložene različitim situacijama u interakciji s drugim jedinkama. Stoga, predviđanje ponašanja drugih, pomoću informacija dobivenih opažanjem, može biti korisno u budućim interakcijama. Kako su u prijašnjim studijama gavrani razlikovali ljude nakon direktne interakcije s njima, zanimalo me mogu li razlikovati ljude i iz pozicije promatrača. U ovom eksperimentu, svaki je gavran promatrao dva izvođača pokusa koji su ili uzeli hranu koju su sami prethodno sakrili ili su ukrali hranu iz skrovišta drugog izvođača pokusa. Naknadno, dva izvođača pokusa (kradljivac ili osoba koja je uzela svoju hranu natrag i neutralna osoba) ponudili su hranu gavranu, koji je ...