Many vertebrate species show display behaviors when predators are in their vicinity. Some of these displays may inform the predator of the improbability of capturing the prey (i.e., pursuit-deterrent displays) and are potentially advantageous to both predator and prey. Here we present data on a tail display performed by Gonatodes albogularis, a diurnal tropical gecko. We performed transect surveys in three habitats near Bogotá in Colombia. Geckos detected during transects were approached by the observer in a standardized way, and details of their tailwaving displays were recorded. In control recordings animals were watched from a distant site without approaching them. Results showed sexual differences in tail-waving display: when approached by the observer, males performed this behavior more frequently than females. We found no significant differences between males and females in flight-initiation distances and height above the substratum when they were initially located. Results also showed that males displayed more frequently when approached than when the simulated predator remained stationary. We interpret these results as evidence that the display functions as a pursuit-deterrent signal to potential predators. However, as some tail displays were performed in the presence of conspecifics, the display may also have a social function.

Objective: to establish whether the Canadian selfreport altruism scale Questionnaire is a reliable estimate for altruistic behavior in young Colombian university students.Methodology: the self-report altruism scale test was adapted and applied. 327 university students between 18 and 25 years from five independent cohorts participated in this study. Participants should note, in 20 items, the frequency (never, once, more than once, often or very often) with which they performed altruistic behavior. The method of this study followed the protocol of the World Health Organization for these cases. There was also a correlation analysis between the score of the questionnaire and the evaluation that some close friends of each participant made in relation to the altruistic tendency of the latter.Results: cronbach's alpha, bipartition analysis and comparison of these data with those reported in other countries show that the instrument is highly reliable. The selfreport altruism scale questionnaire is a useful tool to estimate the altruistic behavior of Colombian university students.Conclusions: the relevance of developing tools to assess prosocial behavior in the country is discussed and clarified. Expanding the age range and applying the questionnaire to non-university populations, will strengthen the development of the instrument.