RESUMO
Maned wolves (Chrysocyon brachyurus) are monogamous and display biparental care for their young, although adults rarely spend time in close proximity. To better understand vocal interactions of maned wolves over long-distances, we passively recorded >10 months of audio data in the species' natural habitat and analyzed manual recordings of captive animals, covering the reproductive and non-reproductive seasons. In the natural habitat recordings, we found that maned wolves engage in vocal exchanges (termed interactive sequences) more often during the mating season, suggesting the existence of a partner attraction/reunion/guarding function, and also during the initial parental care period, suggesting communication among caregivers. We analyzed 21 interactive sequences, which were the only instances in which we could distinguish individuals, and found that the individuals interacting differed significantly in their roar-bark parameters, including duration, which also differed between males and females in captivity (male vocalizations were, on average, 0.124 s longer). We also found that interactive sequences in captive animals, involving two or more participants, almost always involved both sexes. These results suggest that acoustic interacting maned wolves are most likely male−female dyads.
RESUMO
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.
RESUMO
Treatment of major depression, posttraumatic stress disorder and other psychopathologies with antidepressants can be associated with improvement of the cognitive deficits related to these disorders. Although the mechanisms of these effects are not completely elucidated, alterations in the extinction of aversive memories are believed to play a role in these psychopathologies. We have recently verified that female rats present low levels of extinction when submitted to the plus-maze discriminative avoidance task. In the present study, female rats were treated long term with clinically used antidepressants (fluoxetine, nortriptyline or mirtazapine) and subjected to the plus-maze discriminative avoidance task to evaluate learning, memory, extinction and anxiety-related behaviors as well as behavioral despair in the forced swimming test. All groups learned the task and exhibited retrieval. Chronic treatment with fluoxetine (but not with the other antidepressants tested) increased extinction of the discriminative task. In the forced swimming test, the animals treated with fluoxetine and mirtazapine showed decreased immobility duration. In conclusion, fluoxetine potentiated extinction, while both fluoxetine and mirtazapine were effective in ameliorating depressive-like behavior in the forced swimming test, suggesting a possible dissociation between the effects on mood and the extinction of aversive memories in female rats.
