How does hunting pressure affect caribou behavior in the tundra?

Altered Migration Patterns

When hunting pressure increases, caribou in the tundra tend to alter their migration patterns to avoid areas with high human activity. This can lead to them moving further north or south than their traditional migration routes, which can put additional stress on their bodies due to the harsher climate conditions. For example, in Alaska, a study found that caribou migrated an average of 50 miles (80 km) further north than usual to avoid hunting pressure.

Changes in Grazing Habits

Hunting pressure can also cause caribou to change their grazing habits. In areas with high hunting pressure, caribou tend to graze on lower-quality lichen and berries, which can lead to malnutrition and a decline in their overall health. For example, in the Arctic tundra, caribou typically graze on high-quality lichen during the summer months, but in areas with high hunting pressure, they may switch to lower-quality lichen, such as reindeer lichen, which is lower in nutrients.

Increased Vigilance

Caribou in areas with high hunting pressure also tend to be more vigilant, spending more time scanning their surroundings for potential threats. This can lead to increased energy expenditure and decreased foraging time, which can further exacerbate malnutrition. In the tundra, caribou typically spend around 20-30% of their time grazing, but in areas with high hunting pressure, they may spend as little as 10-20% of their time grazing due to increased vigilance.