The social behaviour of rodents has captivated scientists for decades, offering valuable insights into the evolution of mammalian sociality. One of the main critical gaps in understanding rodent sociality is the role of subadult individuals prolonging their stay with parents and younger siblings, particularly in nocturnal and elusive species. Moreover, urban environments are known to elicit changes in the social behaviour of mammals, leading to altered patterns of sociality. Yet, little is known on how rodent societies may change in altered environments. Thus, we aimed at investigating the social behaviour of the crested porcupine Hystrix cristata in central Italy, with a particular focus on group composition and on the prolonged occurrence of subadult individuals within family groups. We also tested the potential effects of natural and urban environments. We combined marking of free-ranging individuals with camera trapping campaigns across three ecologically contrasting areas, and showed a pair-living social system for adult crested porcupines. Most videos captured either single young individuals or pairs of adults. Subadult marked females were observed together with adults during the birth season in the year following their birth, suggesting a potential helping role. Conversely, subadult marked males were rarely observed, presumably dispersing. Groups exceeding two individuals ranged between three and five, and were typically observed following reproductive events, with porcupines commuting in line, parents positioned at head and tail of the row. Urban environments showed a slightly different pattern, with occasional aggregations of subadults. We highlight the importance of understanding subadult behaviour in crested porcupines, as well as of testing the effects of urban ecosystems upon mammalian social systems. These findings contribute to a broader understanding of social behaviour and evolutionary adaptations in rodents and, more in general, of mammals.

The emerging field of macrobehaviour explores behavioural variation across large geographic, taxonomic, and temporal scales, and its ecological and evolutionary consequences. This unifying framework merges macroecology with ethology, both enhancing our understanding of how behaviour mediates ecological dynamics at scales above the population level, and offering an approach that can broaden the impact of ethological research. Here, I urge ethologists to engage with the field, outlining what “macro” means, why we must act now, why we need your expertise, how you can get involved, and how this line of research offers reciprocal benefits to both disciplines. Together, we can amplify the impact of ethological research while accelerating insight that could inform solutions to the global biodiversity crisis.

The present study reports a decrease in activity and sudden immobile state, known as thanatosis, in the New Zealand endemic wrasse, Notolabrus celidotus. We observed tonic immobility immediately after wrasse collection in field studies. Escape is the primary defence of juvenile N. celidotus and our observation suggests that thanatosis can be a secondary strategy when the first has failed. The response occurred after N. celidotus was manipulated by being removed from a fishnet and placed into buckets, allowing for the conclusion that N. celidotus may use thanatosis as a secondary defence strategy following physical restraint events.

The common cuckoo Cuculus canorus is an obligate brood parasite of many Eurasian bird species that exploit the parental care of their hosts. Although only females lay eggs in nests of passerine hosts, male and female cuckoos should cooperate to have a success in nest parasitism. Many bird species mobbing cuckoos as an element of deterrence of cuckoos from the breeding territory of the host. However, mobbing behaviour is costly, although only cuckoo females pose a threat to the dangers of the host. Because only the presence of a female cuckoo is dangerous, due to laying eggs in the nests of hosts, birds should mainly attack cuckoo females. Therefore, we tested for differences in anti-parasite response using field experiments with female and male cuckoo dummies, in 92 breeding sites with prime habitats in Poland. tested for differences in cuckoo responses in anti-parasite response using field experiments and cuckoo dummies (male and female) placed at 92 breeding sites with prime habitats in Poland. The host species that behaved most aggressively towards cuckoos was the barn swallow Hirundo rustica, while the most aggressive behaviour recorded in the non-host group was the great tit Parus major. Generally, host species reacted to cuckoo female dummies with a significantly higher probability than cuckoo males dummies. We conclude that differences in reaction by hosts and non-hosts may have arisen from selection for recognition of danger (parasite female) by reduction of reproductive success.