A Gnawing Question: How Do Caribou and Other Arctic Mammals Exploit Shared Bone Resources?

Area of Science:

• Ecology
• Evolutionary Biology
• Wildlife Biology

Background:

• Resource partitioning of animal bones by various species is poorly understood.
• Female caribou (Rangifer tarandus) antlers are a unique nutrient source, shed on calving grounds.

Purpose of the Study:

• To evaluate bone resource partitioning by co-occurring species on caribou calving grounds.
• To investigate the ecological and evolutionary implications of bone consumption, particularly antler osteophagy.

Main Methods:

• Analysis of bone modification features on shed caribou antlers and skeletal bones.
• Identification of modifying species (caribou, carnivorans, rodents) based on bone modifications.

Main Results:

• 86.4% of shed antlers were modified, primarily by caribou (99%).
• 44.2% of skeletal bones were modified, predominantly by carnivorans (91.9%).
• Carnivorans preferred skeletal bones, likely due to higher fat content.

Conclusions:

• Caribou extensively consume shed antlers, indicating their significance as a nutrient resource (Ca, P) for maternal and calf health.
• Osteophagy of antlers may have driven the evolution and maintenance of antlers in female caribou and their shedding timing.
• Antler accumulation could enhance calving ground fidelity by providing a mineral reservoir.