Influences on the balance between energetics and risk in snowshoe hares

Monk, Emily (2025) Influences on the balance between energetics and risk in snowshoe hares. Masters thesis, Memorial University of Newfoundland.

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Abstract

Animals balance acquiring food for energy while minimizing their risk of predation, but climate or habitat features can tip the scales. I used snowshoe hare (Lepus americanus) to test how external variables influence foraging and survival. First, I used winter coat-colour mismatch to test the Camouflage Hypothesis. I predicted that white hares mismatched on a snowless winter background would be more vulnerable to predation than matched hares. Instead, mismatched hares had lower mortality risk than matched hares. Temperature and snow depth, not mismatch, influenced survival and foraging behaviour. Next, I tested the Risk Allocation Hypothesis with a novel risk simulation experiment in the context of spring environmental factors. Hares did not allocate risk based on simulated risk or weather conditions. Instead, hares were risk averse as a function of canopy cover. Taken together, my results demonstrate that multiple mechanisms likely impact the energetics-risk balance. Snow depth and canopy cover have direct implications on predation risk, while temperature impacts energetics; however, effects may not be detectable if conditions do not represent an energetic challenge. My work highlights the idiosyncrasies of place considering previous results across the hare range, and contributes to mismatch and behavioural frameworks for a seasonally coat-colour changing species.

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