Biology subjects

Damini, S.

Publications and source records attributed to Damini, S..

3 recordsLinked to original sources

bioRxiv2025

Sex, not familiarity, shapes social interactions in adult tortoises (Testudo hermanni)

Social cohesion varies across species. Solitary animals minimise social contact to reduce costs such as resource competition, aggression, and disease transmission. Solitary Testudo hatchlings can rely on familiarity to avoid unfamiliar conspecifics. It remains unclear whether this strategy is used in adult captive tortoises and whether sex differences exist. To address these questions, we experimentally investigated a colony of captive Testudo hermanni tortoises (a vulnerable species), housed in outdoor enclosures. After a group familiarisation phase, we tested adult tortoises in a novel arena with either a familiar or an unfamiliar same-sex individual (not encountered for at least 3 months). Contrary to our expectations, familiarity had no significant effect on social cohesion measures such as inter-individual distance or facing orientation, showing that in adult captive tortoises familiarity had limited effect on social cohesion. In contrast, we found striking sex differences: males approached conspecifics quickly and remained in close proximity throughout the test, frequently displaying aggression; females initially explored the partner but then distanced themselves, with minimal aggression, similarly to what Testudo hatchlings have been observed to do with unfamiliar individuals. These results show that in adult captive tortoises adult social interactions and social cohesion are influenced by sex. This study provides insight into social cohesion and interaction strategies in tortoises, relevant for captive settings and conservation planning.

animal behavior and cognition↗

bioRxiv2021

Recognition of familiar objects in tortoise hatchlings (Testudo spp.)

Tortoises do not show parental care and live solitary except for the context of reproduction. Despite their limited need to interact with conspecifics, we previously observed that young tortoises, at their first experiences with conspecifics, can discriminate between familiar and unfamiliar conspecifics after just one encounter with another tortoise. Tortoise hatchlings ignored familiar conspecifics, while they first explored and then actively avoided unfamiliar conspecifics. It remains to be established whether the different reactions to unfamiliar and familiar individuals in tortoise hatchlings are reactions to novelty, or whether they are specific to the interactions with living animals. To test this, we familiarized one-month-old tortoise hatchlings with an object (a brown cone vs. a blue sphere) and then tested them in a novel arena once with the familiar object and once with an unfamiliar one. To measure the reactions toward familiar and unfamiliar objects, we measured the distance between the tortoise and the object throughout the test. Differently from what happened with unfamiliar and familiar conspecifics, we found no difference in behavior toward familiar and unfamiliar objects. This shows that the different reactions toward familiar and unfamiliar conspecifics previously observed are specific for social interactions and are not a mere reaction to the novelty effect. The behavioral responses displayed by young tortoises for unfamiliar conspecifics, but not for unfamiliar objects, show the relevance of social behavior from the beginning of life, even for solitary species.

animal behavior and cognition↗

bioRxiv2017

Born to be asocial: newly-hatched tortoises spontaneously avoid unfamiliar individuals

Individual recognition is important for modulating social interactions but it is not clear to what extent this ability depends on experience gained through repeated interactions with different individuals. In wild tortoises, evidence of social interactions is limited to behaviours performed years after hatching, in the context of mating. To investigate the presence of abilities of individual recognition at the onset of life in tortoises, we used hatchlings of two species (Testudo marginata, Testudo graeca) reared with a single conspecific as unique social experience. When located in a novel environment together with the familiar conspecific, tortoises reached the average distance expected by random trajectories. On the contrary, tortoises tested with an unfamiliar conspecific first explored the mate, then actively kept a distance significantly larger than expected by chance. These results show spontaneous abilities of individual recognition in a non-social species at the onset of life, and active avoidance of unfamiliar conspecifics. We suggest that this predisposed behaviour might be adaptive for young tortoises dispersal.

animal behavior and cognition↗