A pet hedgehog lives in a narrow comfort band: she needs a reliably warm room to stay healthy, yet a heatwave can push an enclosure, especially a glass or plastic-sided one, well past what she can cope with. Because hedgehogs are nocturnal, the danger window is the hot evening and night when she wakes, tries to run and eat, and overheats while the household is asleep or winding down, so heatwave care has to be arranged before dark rather than improvised at midnight.
Stabilise the room before adding gadgets
Check the temperature where the enclosure actually sits, with a thermometer at cage level, not the hallway thermostat, since a cage near a window or above a heat-retaining floor runs hotter than the room average. Move the enclosure out of sun reach and away from radiators and conservatory glass, keep air circulating in the room without a fan aimed straight into the cage, and draw curtains through the afternoon peak. Solid-sided enclosures trap heat and stale air, so ventilation matters as much as shade: lids propped for airflow must still be escape-proof for a determined climber. If nights stay very hot, moving the whole setup to the coolest room for the spell is kinder than nightly emergency measures in a hot bedroom.
Give her a cool zone and protect her water and appetite
A ceramic tile or smooth stone slab in one corner, cooled in the fridge, creates a voluntary cold spot she can sprawl on or ignore, which respects how hedgehogs regulate themselves by moving between zones. Offer water in a heavy, tip-proof bowl as well as checking any bottle, because a hot hedgehog drinks more and a bowl cannot jam. Keep food offerings normal and fresh, removing uneaten fresh items by morning so heat-spoiled food does not sit in the cage. Expect some appetite dip and daytime restlessness during extreme heat, and weigh her if the spell lasts, since small losses are visible early on a hedgehog's frame. Keep a second tile chilling in the fridge so a warmed one can be swapped without leaving her corner bare. Avoid cold baths, ice packs against the body, or misting her face, all of which shock rather than help an animal built for gradual change.
Read the night-time warning signs correctly
A hedgehog sprawled flat on her belly with legs splayed is dumping heat and is a picture of an animal at her limit; panting, drooling, wobbliness, or failure to curl or respond as usual escalates that to an emergency needing gradual cooling and a vet call straight away. Move her to the coolest room, place her near, not on, a wrapped cool bottle, and offer water while you seek advice. Cold is the opposite trap once the spell breaks: a hedgehog who becomes sluggish and wobbly as temperatures fall sharply needs warmth restored steadily and the same prompt advice. Writing the household plan down, with the comfortable range, the tile routine, and the signs that mean phone the vet, and pinning it where every carer reads it in KinsLe under Family Sharing prevents the classic heatwave muddle of one person helping with ice while another moves the cage back into the sun.