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The role of spatial distribution of faeces in coyote scent marking behavior

Barja I., List G.

Polish Journal of Ecology

2014

Vol. 62, nr 2

373--384

Scats are important for chemical communication in many canids, however, little is known about the faecal marking behaviour in coyotes. In this study we tested if faeces have a function as visual and scent marks during the non-breeding period, analyzing the spatial characteristics of defecation places. We predicted that if faeces are used as chemical signals, these should be deposited in substrates and/or zones that enhance their detection by conspecifics as it happens in other canid species. The study was conducted in native grasslands at the NW limit of the Chihuahuan Desert. Results showed that the proportion of faeces in conspicuous zones (91.3%) was significantly higher than those on inconspicuous zones (8.7%). However, the number of faeces deposited on inconspicuous substrates (92.1%) was significantly higher than on conspicuous substrates (7.9%). Most faeces were on the ground (99.2%) and only 0.8% where raised. 35% of faeces were deposited in crossroads, being these strategic zones repeatedly marked by the coyotes. We observed a significant negative correlation between the number of faeces in crossroads and the distance of faeces to the centre of the crossroad. A high number of scats were found in the proximity of livestock carcasses (21%). In addition, a selection of certain road sections (track and lateral) was observed. Our results suggest that the scats have an important function as scent-marks in coyotes, using specific defecation patterns that appear to correspond to the habitat characteristics in the study area.

Characterization of Dynamic Friction Factor for FEM Modeling of High Speed Process

Arnoux J. J., Sutter G., List G.

Engineering Transactions

2012

Vol. 60, iss. 3

205-205

The present study aims to establish through a series of friction tests the trends of the dynamic factor according to sliding speed. A ballistic set-up using an air gun launch is used to measure the friction coe?cient for the steel/carbide contact between 15 m/s and 80 m/s. Since the experimental characterization of friction is a key factor in the development of high speed process such as high speed machining, the experimental quantification is introduced into a cutting model by finite elements method. Modeling results are compared with cutting forces measured on a similar experimental device, which can reproduce perfect orthogonal cutting conditions.