1,721,002 research outputs found
The Missing Lemur Link: An Ancestral Step in Human Evolution.
No full textLemurs share a common distant ancestor with humans. Following their own evolutionary pathway, lemurs provide the ideal model to shed light on the behavioural traits of primates including conflict management, communication strategies and society building and how these aspects of social living relate to those found in the anthropoid primates. Adopting a comparative approach throughout, lemur behaviour is cross-examined with that of monkeys, apes and humans. This book reviews and expands upon the newest fields of research in lemur behavioural biology, including recent analytical approaches that have so far been limited to studies of haplorrhine primates. Different methodological approaches are harmonised in this volume to break conceptual walls between both primate taxa and different disciplines. Through a focus on the methodologies behind lemur behaviour and social interactions, future primate researchers will be encouraged to produce directly comparable results
Multimodal signaling in wild Lemur catta: economic design and territorial function of urine marking.
No full textUrine marking has been neglected in
prosimian primates. Captive studies showed that the
Malagasy prosimian Lemur catta scent marks with
urine, as well as via specialized depositions. L. catta
urine mark, a multimodal signal, differs from simple urination
in terms of different design features, including
tail configuration: the tail is held up during marking
(UT-up) and down during urination (UT-down). We
explore economy and function of UT-up in the female
dominant L. catta. We collected 240 h of observations on
one group at Berenty (south Madagascar) during the
nonmating period via all occurrences sampling. We gathered
behavioral bouts/contexts (marking, traveling, feeding,
resting, and fights) and recorded 191 UT-ups and 79
UT-downs. Via Global Positioning System we established
the location of the places frequented i) by extragroup
individuals and ii) by group members, in this case recording
also behavioral context and time spent in each
place. We found that L. catta UT-up is not an artifact of
captivity. Moreover, UT-up in the nonmating period
plays a role in territorial defense, which is mostly performed
by females in L. catta society. Female UT-ups
were the most investigated and UT-ups were performed/
investigated more by females. Finally, signal use is parsimonious,
in that urine is economically placed where
and when detection probability by competitors is higher.
UT-ups were performed in places most frequented by
extragroup individuals and in presence of extragroup
competitors (nonrandom topography and timing). In conclusion, we suggest that UT-up is an economical signal
with a primarily territorial function
Berenty 2006: census of Propithecus verreauxi and possible evidence of population stress
No full textWe provide a survey of a folivorous lemur, Propithecus verreauxi (sifaka),
in the Berenty Reserve, southern Madagascar. Higher densities of folivores in small
patches occur in either high-quality food areas or in less disturbed refugia. The
skewness of sex ratio, which in lemurs is often male-biased, can be critically
exacerbated in population stress. We predicted that sifaka would show higher
densities in areas where protein-rich food is abundant (prediction 1a) and in
refugium areas (prediction 1b). Owing to increased competition by brown and ringtailed
lemurs and decreased food production by tamarind trees, we expected an
extremely male-biased sex ratio (prediction 2). In November–December 2006, we
counted and sexed 206 adult/subadult sifaka (49 groups) during daily walks in
different forest zones (Ankoba secondary forest, to the north, Malaza gallery/scrub
areas, and spiny forest, to the south). Sifaka may have decreased in the gallery forest
to concentrate in Ankoba (in a sort of out-of-Malaza). The area contains protein-rich
food (prediction 1a confirmed). Sifaka are proportionally more concentrated in the
spiny area than in the degraded scrub forest (prediction 1b confirmed). The sex ratio
is extremely male biased, possibly due to either high sifaka density, in Ankoba, or
food availability reduction, in Malaza (prediction 2 confirmed). The sifaka
population seems to be under stress: researchers need to resume demographic
studies, interrupted in Berenty in the mid-1980s, to preserve in situ a species that is
difficult to protect ex situ
Bonobos Protect and Console Friends and Kin
Full text linkPost-conflict third-party affiliation has been reported to have different functional meanings, one of them being consolation. Here, we tested the main hypotheses that have been put forth to explain the presence of this phenomenon at a functional level in the bonobo: Self-Protection Hypothesis, Victim-Protection Hypothesis, Relationship-Repair or Substitute for Reconciliation Hypothesis, and Consolation Hypothesis. By analyzing the data collected over 10 years, we investigated what factors affected the distribution of both spontaneous third party affiliation (initiated by the bystander) and solicited third party affiliation (initiated by the victim). We considered factors related to the individual features (sex, rank, age) of victim and bystander, their relationship quality (kinship, affiliation), and the effect that third party affiliation had on the victim (such as protection against further attacks and anxiety reduction). Both spontaneous and solicited third party affiliation reduced the probability of further aggression by group members on the victim (Victim-Protection Hypothesis supported). Yet, only spontaneous affiliation reduced victim anxiety (measured via self-scratching), thus suggesting that the spontaneous gesture - more than the protection itself - works in calming the distressed subject. The victim may perceive the motivational autonomy of the bystander, who does not require an invitation to provide post-conflict affiliative contact. Moreover, spontaneous - but not solicited - third party affiliation was affected by the bond between consoler and victim, being the relationship between consoler and aggressor irrelevant to the phenomenon distribution (Consolation Hypothesis supported). Spontaneous affiliation followed the empathic gradient described for humans, being mostly offered to kin, then friends, then acquaintances. Overall, our findings do not only indicate the consolatory function of spontaneous third-party affiliation but they also suggest that consolation in the bonobo may be an empathy-based phenomenon
Fragment quality and distribution of the arboreal primate Propithecus verreauxi in the spiny forest of South Madagascar.
No full textThe increasing proportion of the landscape used by humans has led, and is still leading, to the conversion of the original habitat into numerous small patches, often separated by a matrix of inhospitable land-uses. This habitat fragmentation is a major threat to biological diversity and is considered to be the primary cause of the present species extinction crisis (Aurambout et al. 2005). Survival in fragments is related to both intrinsic factors, such as abundance and sex ratio, and extrinsic factors related to patch quality (Ramanamanjato & Ganzhorn 2001, Rovero & Struhsaker 2007). At first, the fragmentation process can randomly distribute animals among forest patches and across fragmented habitat and surrounding matrix (Marsh 2003, Tischendorf et al. 2005). Local populations can survive only if the colonized forest remnants are adequate and/or dispersal is possible (Marsh 2003). Subsequently, a non-random distribution can result from local populations either remaining connected but distinct (metapopulation) or merging into a single large but patchy population (Harrison & Taylor 1997). Such distribution can be dictated by different aspects of fragment quality, including size and vegetation variables (e.g. tree species diversity, large-tree abundance and food plant availability) (Ramanamanjato & Ganzhorn 2001, Rovero & Struhsaker 2007). The mutual relationship among variables and their linkage to animal abundance have proven difficult to disentangle and mammals largely diverge in their response to different fragment quality aspects (Irwin 2008, Ramanamanjato & Ganzhorn 2001, Rovero & Struhsaker 2007).</jats:p
The socio-matrix reloaded: from hierarchy to dominance profile in wild lemurs
Full text linkDominance hierarchy influences the life quality of social animals, and its definition should in principle be based on the outcome of agonistic interactions. However, defining and comparing the dominance profile of social groups is difficult due to the different dominance measures used and because no one measure explains it all.We applied different analytical methods to winner-loser sociomatrices to determine the
dominance profile of five groups of wild lemurs (species: Lemur catta, Propithecus verreauxi, and Eulemur rufus x collaris) from the Berenty forest (Madagascar). They
are an excellent study model because they share the same habitat and an apparently similar dominance profile: linear hierarchy and female dominance. Data were collected
over more than 1200 h of observation. Our approach included four steps:
(1) by applying the binary dyadic dominance relationship method (I&SI) on either aggressions or supplant sociomatrices we verified whether hierarchy was aggression
or submission based; (2) by calculating normalized David’s scores and measuring steepness from aggression sociomatrices we evaluated whether hierarchy was shallow
or steep; (3) by comparing the ranking orders obtained with methods 1 and 2 we assessed whether hierarchy was consistent or not; and (4) by assessing triangle transitivity and comparing it with the linearity index and the level of group cohesion we determined if hierarchy was more or less cohesive. Our results show that L. catta groups have got a steep, consistent, highly transitive and cohesive hierarchy. P. verreauxi groups are characterized by a moderately steep and consistent hierarchy, with variable levels of triangle transitivity and cohesion. E. rufus x collaris group possesses
a shallow and inconsistent hierarchy, with lower (but not lowest) levels of transitivity and cohesion. A multiple analytical approach on winner-loser sociomatrices other
than leading to an in-depth description of the dominance profile, allows intergroup and cross-species comparisons
Translating museum visual contents into descriptions for blind User: a multidisciplinary approach
No full textAccessibility and usability guidelines are available to design web sites accessible to blind users. However, the actual usability of accessible web pages varies depending on the type of information the user is dealing with. Museum web sites, including specimens and hall descriptions, need specific requirements to allow vision-impaired users, who navigate using a screen-reader, to access pieces of information that are mainly based on visual perception. Here we address a methodology to be applied for the proper creation and elaboration of alternative image descriptions in museum web pages. Such methodology has been applied to a gallery of the Museum of Natural History and Territory (University of Pisa). Such indications allow the user: (1) to address indexed contents and to link to information in more details, (2) to calibrate image descriptions (with a command providing alternative explanations for specimens), and (3) to access extra information for the blind (via hidden labels). A multidisciplinary approach is necessary to obtain effective and comprehensive descriptions. In this perspective, a cooperative environment is eventually proposed for team work facilitation
Peacemaking on treetops: first evidence of reconciliation from a wild prosimian (Propithecus verreauxi).
No full textReconciliation is defined as the first postconflict affinitive contact between former opponents. While
reconciliation in anthropoid primates has been widely investigated, few studies have focused on postconflict
mechanisms in prosimians, and only in captivity. Unlike anthropoids, Malagasy prosimians show female
dominance, lack of sexual dimorphism and seasonal breeding. However, they share features with
anthropoids such as cohesive societies, female philopatry and individual recognition. Comparing social
prosimians with anthropoids is crucial for understanding the evolution of reconciliation dynamics.
Here we present the first study on reconciliation in a wild prosimian. We focused on the Propithecus verreauxi
(sifaka) of the Berenty forest (southern Madagascar). We examined postconflict behaviour in the
light of theoretical expectations based on potential costs and benefits of the individuals involved. Our results
indicate that P. verreauxi can evaluate possible risks and benefits of engaging in postconflict reunions.
Victims were most likely to interact affinitively with the aggressor after low-intensity aggression. Moreover,
only the conflicts occurring outside the feeding context were reconciled. Such results are consonant with
the fact that, in P. verreauxi, social dominance is translated more into feeding priority than into a framework
of despotic relationships. In agreement with the valuable relationship hypothesis, P. verreauxi were more
likely to reconcile with valuable partners: reconciliation preferentially occurred between subordinates
and top-ranking individuals, and between animals sharing good relationships (high levels of affinitive
behaviours). Over the short term, reconciliation in P. verreauxi seems to have an important role in reducing
the probability of further attacks by the aggressor
Virtual visit of the Primate Gallery of the Museum of Natural History and Territory (University of Pisa): accessibility and usability for blind users
No full textUsability guidelines are available to design web site visits accessible to the blind users. However, the actual usability of accessible web pages changes depending on the type of information the user is dealing with. Museum web sites including specimen/exhibition hall descriptions need specific requirements to allow vision-impaired users, who navigates using a screen-reader (a device that reads the text of the page), to access pieces of information based on a visual perception. Here we address the additional usability guidelines applied to the web pages describing the Primate Gallery of the Museum of Natural History and Territory (University of Pisa)
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