Wildlife Elective Course Essay

• Main Author: Silje Karlsen
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Svalbard; Tromsø; Lagopus mutus
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.628.711; http://www.behav.org/student_essay/concept/karlsen_photoperiod_svalbart_ptarmigan.pdf

The photoperiods influence on the Svalbart ptarmigan, Lagopus mutus hyperboreus. Svalbard, 79o N, is a part of the arctic, defined by the 10o isotherm for the warmest summer month. Animals here are exposed for extreme climates both in temperature and variation in daylight throughout the year. The Svalbard ptarmigan is the only resident bird that lives permanently at such high latitudes. Here the sun stays below the horizon for two months and cause total darkness from mid of November to February, while in the summer the sun stays above the horizon permanently and gives continuous daylight. It has been necessary for the svalbard ptarmigan to develop some adaptions for surviving in such a hash climate, like behavioural changes and deposition of huge stores of fat. It is therefore interesting how the photoperiods influence on the svalbard ptarmigans FI (food intake) and BW (body mass) throughout the year. The university in Tromsø has done some research on these subjects, where they’ve tested the bird’s reactions to light and measured the concentration of plasma melatonin, which is a hormone that usually is low during the day and high during the night. The blood sample was