Background: The organochlorine DDT has estrogenic activity but the mechanism underlying the estrogenic activity of this pesticide remains unclear. In the present investigation here, we studied the transcriptional effects of a synthetic organochlorine pesticide o,p’-DDT [1.1.1.-trichloro-2-(o-chlorophenyl)-2-p-chloriphenyl ethane] and its metabolite p,p'-DDE (2-2-bis(4/chlorophenyl)-1-1-di...

The ‘pay-to-stay hypothesis’ proposes that subordinate group members help dominants in order to be tolerated in the territory. Accordingly, helpers should be punished if they are not helping sufficiently and should increase helping behaviour thereafter. We tested whether helping and social behaviours of group members of the cooperatively breeding cichlid Neolamprologus pulcher change according ...

Predators are a ubiquitous presence in most natural environments. Opportunities to contrast the behaviour of a species in the presence and absence of predators are thus rare. Here we report on the behaviour of howler monkey groups living under radically different conditions on two land-bridge islands in Lago Guri, Venezuela. One group of 6 adults inhabited a 190-ha island (Danto) where they wer...

California sea lions aggregate in high density colonies during the breeding season. Competition for space and mates results in agonistic interactions that may have long-term population consequences. We explored how demographic, behavioral, and environmental variables influence the rate of agonistic interactions in male and female California sea lions at three breeding colonies with varying popu...

Belugas (Delphinapterus leucas) in managed care have been reported to show seasonal variation socio-sexual behaviour, hormone levels and respiration rates; however, little is known about the social interactions of wild belugas when they are not summer, near-shore congregations. To better understand if interactions, this study recorded behaviour 10 (five females, five males, ranging from birth y...

A biological control strategy relying on a self-disseminating agent may provide the only affordable long-term technique for reducing brushtail possum (Trichosurus vulpecula) numbers throughout New Zealand. The objective of this study was to determine the frequency and patterns of social interactions in single and mixed-sex groups of possums, in order to identify interactions that may assist in ...

BACKGROUND Sound production is widespread among fishes and accompanies many social interactions. The literature reports twenty-nine cichlid species known to produce sounds during aggressive and courtship displays, but the precise range in behavioural contexts is unclear. This study aims to describe the various Oreochromis niloticus behaviours that are associated with sound production in order t...

Fluorescence enables the display of wavelengths that are absent in the natural environment, offering the potential to generate conspicuous colour contrasts. The marine fairy wrasse Cirrhilabrus solorensis displays prominent fluorescence in the deep red range (650-700 nm). This is remarkable because marine fishes are generally assumed to have poor sensitivity in this part of the visual spectrum....

Reason can be defined in many ways, and more than one definition would fertile ground for investigation the Ajax. Perhaps most tempting way to understand Reason, especially given theme of insanity play, is as sanity; however, might also understood an interpersonal phenomenon, ability individuals ‘reason’ together, negotiating arguing reach agreement. It this agonistic (agonistic that it what ch...