Time filter

Source Type

Rome, Italy

Cafazzo S.,University of Parma | Natoli E.,Azienda USL Rome D | Valsecchi P.,University of Parma
Ethology | Year: 2012

Most mammals scent-mark, and a variety of hypotheses have been put forward to explain this behaviour. Most of our knowledge about scent marking in domestic dogs comes from studies carried out on laboratory or companion dogs, while few studies have been carried out on free-ranging dogs. Here, we explored the functional significance of different scent-marking behavioural patterns in a pack of free-ranging domestic dogs by testing two non-exclusive hypotheses: the indirect territorial defence and the dominance/threat hypotheses. Through direct observation, we recorded the locations of dog scent marks (urination, defecation and ground scratching) and information regarding the identity and posture of the marking animal. We found evidence that markings are used by dogs to form a 'property line' and to threaten rivals during agonistic conflicts. Both males and females utilized scent marking to assert dominance and probably to relocate food or maintain possession over it. Raised-leg urination and ground scratching probably play a role in olfactory and visual communication in both males and females. Urinations released by females, especially through flexed-leg posture, may also convey information about their reproductive state. Finally, our observations suggest that defecation does not play an essential role in olfactory communication among free-ranging dogs and that standing and squat postures are associated with normal excretion. Our results suggest that many of the proposed functions of marking behaviours are not mutually exclusive, and all should be explored through detailed field and laboratory studies. © 2012 Blackwell Verlag GmbH. Source

A study on cancer of the lymphatic and hematopoietic tissue among residents aged 0-14 years was conducted by the Local Health Unit RMD (Rome, Italy; period 2003-09; codes of the International Classification of Diseases, Ninth Revision, Clinical Modification: 200-208). Age and gender Standardized Mortality and Hospitalization Ratios were computed in order to compare observed and expected cases, using municipal rates as reference. Place of residence at the time of admission, as recorded in the Hospital Registry, was compared with the information recorded in the Municipal Registers and the correlation between the two sources was calculated by Cohen's Kappa. No mortality nor morbidity excesses were observed in the study area. Although 14% of children were not confirmed as being resident at the time of admission, the Cohen's Kappa indicates a strong correlation between the Municipal Registry and the Hospital Registry (84%). The analyses restricted to children with ascertained residence did not yield different results. For those whose residence was not confirmed, the mismatch of information between the Municipality Registry and the Hospital Registry needs to be clarified. Source

Cafazzo S.,University of Parma | Valsecchi P.,University of Parma | Bonanni R.,University of Parma | Natoli E.,Azienda USL Rome D
Behavioral Ecology | Year: 2010

Current knowledge about social behavior of free-ranging domestic dogs is scarce, and the possibility that they could form stable social groups has been highly debated. We investigated the existence of a social-dominance hierarchy in a free-ranging group of domestic dogs. We quantified the pattern of dyadic exchange of a number of behaviors to examine to what extent each behavior fits a linear rank-order model. We distinguished among agonistic dominance, formal dominance, and competitive ability. The agonistic-dominance hierarchy in the study group shows significant and substantial linearity. As in random assortments of captive wolves, there is a prominent but nonexclusive male agonistic dominance in each age class. The agonistic rank-order correlates positively and significantly with age. Submissive-affiliative behavior fulfills the criteria of formal submission signals; nevertheless, it was not observed among all dogs, and thus, it is not useful to order the dogs in a consistent linear rank. Agonistic-dominance relationships in the dog group remain stable across different competitive contexts and to the behaviors considered. Some individuals gain access to food prevailing over other dogs during competitions. Access to food resources is predicted reasonably well by agonistic rank order: High-ranking individuals have the priority of access. The findings of this research contradict the notion that free-ranging dogs are "asocial" animals and agree with other studies suggesting that long-term social bonds exist within free-ranging dog groups. © 2010 The Author. Source

Bonanni R.,University of Parma | Cafazzo S.,University of Bologna | Valsecchi P.,University of Parma | Natoli E.,Azienda USL Rome D
Animal Behaviour | Year: 2010

Consensus decisions about the nature and timing of group activities allow animals to maintain group cohesiveness, but also entail costs because individuals often differ with respect to their optimal activity budgets. Two mechanisms whereby animals reach a consensus include 'consistent leadership', in which a single dominant individual makes the decision, and 'variable leadership' in which several group members contribute to the decision outcome. Sharing of consensus decisions is expected to reduce consensus costs to most group members. Both patterns are thought to emerge from the complexity of social relationships of group members. We investigated the distribution of leadership during group departures in two packs of free-ranging dogs, Canis lupus familiaris, and tested how its distribution between individuals was affected by dominance rank-related affiliative and agonistic relationships. Although leadership was not entirely concentrated on a single group member, both packs had a limited number of habitual leaders. In the largest pack, the pattern of leadership changed from 'variable' to nearly 'consistent' after its size had shrunk. Habitual leaders were usually old and high-ranking individuals. However, high-ranking dogs that received affiliative submissions in greeting ceremonies were more likely to lead than dominant dogs receiving submissions only in agonistic contexts. During resting times, habitual followers associated more closely with habitual leaders than with other followers. These results suggest that in social species collective movements may arise from the effort of subordinates to maintain close proximity with specific valuable social partners. © 2010 The Association for the Study of Animal Behaviour. Source

Bonanni R.,University of Parma | Valsecchi P.,University of Parma | Natoli E.,Azienda USL Rome D
Animal Behaviour | Year: 2010

Cooperative intergroup aggression provides an example of a costly cooperative behaviour whose benefits spill over to noncooperative animals as well. Consequently, investigating factors that promote individual participation in intergroup contests should prove useful for understanding how cooperation may persist in animal societies despite cheating. Here, we examined variables affecting individual participation in naturally occurring conflicts between groups of free-ranging dogs, Canis lupus familiaris. The overall proportion of cooperating group members decreased significantly with an increasing number of group members present. In one pack, the individual probability of active participation decreased significantly when this pack had a numerical advantage over opponents. Dogs belonging to the smallest pack tended to be more cooperative than those belonging to larger groups. Social prestige (measured as the number of submissions received during greeting) did not appear to be a consequence of cooperative behaviour. Individual participation increased with an increasing number of affiliative partners. Young and high-ranking dogs tended to cooperate more when their group was outnumbered by opponents but did not stay at the front of the pack during conflicts. These results emphasize the greater opportunity for cheating in larger groups and the complexity of dogs' behaviour. Cooperation appears to be conditional on both the 'adversity of the environment' (as measured by relative group size) and the identity/behaviour of companions. © 2010 The Association for the Study of Animal Behaviour. Source

Discover hidden collaborations