Acoustic Monitoring of Black-Tufted Marmosets in a Tropical Forest Disturbed by Mining Noise.

All habitats have noise, but anthropogenic sounds often differ from natural sounds in terms of frequency, duration and intensity, and therefore may disrupt animal vocal communication. This study aimed to investigate whether vocalizations emitted by black-tufted marmosets (Callithrix penicillata) were affected by the noise produced by mining activity. Through passive acoustic monitoring, we compared the noise levels and acoustic parameters of the contact calls of marmosets living in two study areas (with two sampling points within each area)-one near and one far from an opencast mine in Brazil. The near area had higher anthropogenic background noise levels and the marmosets showed greater calling activity compared to the far area. Calls in the near area had significantly lower minimum, maximum and peak frequencies and higher average power density and bandwidth than those in the far area. Our results indicate that the mining noise affected marmoset vocal communication and may be causing the animals to adjust their acoustic communication patterns to increase the efficiency of signal propagation. Given that vocalizations are an important part of social interactions in this species, concerns arise about the potential negative impact of mining noise on marmosets exposed to this human activity.

The Power of Discourse: Associations between Trainers' Speech and the Responses of Socialized Wolves and Dogs to Training.

In a previous study, we found that Positive Reinforcement Training reduced cortisol of wolves and dogs; however, this effect varied across trainer-animal dyads. Here we investigate whether and how the trainers' use of speech may contribute to this effect. Dogs' great interest in high-pitched, intense speech (also known as Dog Directed Speech) has already been reported, but whether and how wolves respond similarly/differently to voice characteristics has never been studied before. We analyzed 270 training sessions, conducted by five trainers, with nine mixed-breed dogs and nine wolves, all human-socialized. Through Generalized Linear Mixed Models, we analyzed the effects of (a) three speech categories (nice, neutral, reprehensive) and laugh; and (b) acoustic characteristics of trainers' voices on animals' responses (correct responses, latency, orientation, time at less than 1 m, non-training behaviors, tail position/movements, cortisol variation). In both subspecies, tail wagging occurred more often in sessions with longer durations of nice speech, and less often in sessions with reprehensive speech. For dogs, the duration of reprehensive speech within a session was also negatively related to correct responses. For wolves, retreat time was associated with more reprehensive speech, whereas duration of nice speech was positively associated with time spent within one meter from the trainer. In addition, most dog behavioral responses were associated with higher average intonations within sessions, while wolf responses were correlated with lower intonations within sessions. We did not find any effects of the variables considered on cortisol variation. Our study highlights the relevance of voice tone and speech in a training context on animals' performances and emotional reactions.

Scale-free distribution of silences.

Soundscape studies help us understand ecological processes, biodiversity distribution, anthropic influences, and even urban quality, across a wide variety of places and time periods. In this work, instead of looking for differences, we ask if there are common characteristics shared by all soundscapes. Based on our results, we propose a universal distribution of quiet-time (background noise) and sound-time (acoustic energy bursts) in audio recordings. We analyzed one continuous hour during daylight and one at night, from ten randomly selected days in each environment: urban, dry forest, savanna, rupestrian field, Atlantic forest, marine, and freshwater. We found that the histograms of the quiet-time followed a power law for all scenarios analyzed, they present fractal events or scale-free distributions. This distribution covers up to four orders of magnitude, with an exponent of 1.6≤α≤2.0 for all soundscapes. By contrast, the sound-time distribution in all environments followed a log-normal or timescale dependence, with a typical time for the duration of sounds (0.06-0.12 s). Such time duration limitation can be related to the physiology of sound emission in animals.

Behavioural and ecological aspects of black tufted-ear marmosets, callithrix penicillata (geoffroy, 1812) (primates: callitrichidae) in a semi-urban environment

The black tufted-ear marmoset (Callithrix penicillata) is a small Neotropical primate, which lives in various types of environments from Cerrado (Brazilian savannah), Atlantic forest to urban areas. Research shows that food availability influences home range size, group size, population density and the behaviour of marmoset groups in the wild. The objective of this study was to investigate the behaviour of C. penicillata in an urbanized habitat, and the influence of (estimated) food availability on home range size, group size and population density. This study was performed through direct behavioural observation (84 hours) on four wild groups of marmosets living within the grounds of Belo Horizonte Zoological garden, Minas Gerais, Brazil. The results show that, despite living in an urban habitat, these marmosets presented home range size (2.85ha), group size (mean=5.7 ind.) and population density (2.19 ind/ha) values in the range found in wild-living conspecifics. The animals studied spent a considerable percentage of their time travelling (22.45%); resting (16.58%), inactive alert (14.95%) and feeding (6.74%). These results showed that behavioural activity repertoires were also found to be similar to wild-living conspecifics and therefore demonstrate the species adaptation capacity in urban environment.

O mico-estrela (Callithrix penicillata) é uma pequena espécie de primata neotropical que vive em vários tipos de ambientes como Cerrado e Mata Atlântica, podendo também ocupar áreas urbanas. Pesquisas já mostraram que a disponibilidade de recurso alimentar afeta a área de vida, o tamanho de grupo e o comportamento da espécie na natureza. Os objetivos deste estudo foram investigar o comportamento do mico-estrela em um ambiente urbanizado e a influência de recurso alimentar (estimado) na área de vida e na densidade populacional. O estudo foi realizado por meio de observações diretas (84 horas) com quatro grupos de mico-estrela vivendo nas dependências do zoológico de Belo Horizonte, Minas Gerais, Brasil. Os resultados mostraram que apesar de viverem em ambiente urbano, estes micos tem áreas de vida (2,85ha), tamanhos dos grupos (média=5,7 indivíduos) e densidades populacionais (2,19 ind/ha) parecidos com os valores obtidos para a espécie nativa. Os animais estudados, passaram a maior parte do dia se deslocando (22,45%), descansando (16,58%), inativos alertas (14,95%) e alimentando-se (6,74%). Estes resultados mostram que o padrão de atividade e o repertório comportamental exibidos pelos animais deste estudo são similares aos apresentados na natureza e portanto, evidenciam a capacidade de adaptação da espécie em ambientes antrópicos.