The Giant Deer Megaloceros giganteus (Blumenbach, 1799) is an icon of the Ice Age due to their famous antlers, although there has been little focus on isotopic analysis of these animals. migrational behaviour in these animals has been suggested, mainly due to this behaviour being common in deer species today. Migrational behaviour and seasonal movement is analysed in three Giant Deer from Ireland dating back to the Pleistocene late glacial through isotopic analysis. Analysis is performed using sequential intra-tooth sampling for 87Sr/86Sr ratios acquired from TIMS and LA-MC-ICPMS on the Giant Deer’s tooth enamel. A comparison between TIMS and LA-MC-ICPMS is performed to try and improve the precision and accuracy of LA-MC-ICPMS for strontium isotopic analysis. This research is conducted as part of a Utrecht University joint MSc thesis.