From around November to late March or early April, hedgehogs settle into a deep, energy-conserving sleep that allows them to survive the cold months when food is scarce.

As temperatures drop, hedgehogs prepare by building nests, or ‘hibernacula,’ typically in piles of leaves, logs, or dense shrubs, which insulate them from the chill and provide protection from predators. During hibernation, their metabolism slows dramatically, their heart rate drops from around 190 to just 20 beats per minute, and their body temperature falls from 35°C to just a few degrees above freezing. This near-dormancy state allows them to conserve fat reserves accumulated during summer and autumn, crucial for surviving winter.

The European hedgehog is one of only three UK mammals that truly hibernate, the others being bats and the hazel dormouse.

The success of hedgehog hibernation, however, is under threat. Habitat loss, climate change, and dwindling food supplies all pose significant risks. Gardens, a key habitat for urban and suburban hedgehogs, are increasingly altered or tidied, reducing the availability of natural nesting sites and food sources.

Gardeners and homeowners can play a vital role in helping hedgehogs over winter. Leaving parts of the garden ‘wild’ with leaf piles, log stacks, or small burrows can provide safe nesting areas for hedgehogs to build hibernacula. Disturbing piles of leaves or shrubs in the winter may lead to waking up hedgehogs from their hibernation and make them use unnecessary energy in the process. Additionally, avoid using pesticides, as these reduce the natural insect populations on which hedgehogs feed upon.

Fun fact: The European hedgehog typically has around 7000 spikes on its back which are actually modified hairs. They will curl up into a ball when threatened, presenting a ball of spikes to their attacker.