My dog overheated on a walk — he's cooling down and seems better, do I still need a vet?

Take him to a vet now, even though he seems to be improving. 'He seems better' is the classic trap with heatstroke, because the worst of the damage announces itself hours later, not in the first hour.

Cool him on the way, not instead of the drive. Get him out of the heat, wet his whole coat with cool water — not ice-cold — keep air moving over him with a fan, or with the car's air conditioning and the windows open, and let him drink if he wants to, but do not force water into him. No ice baths. And do not drape him in soaked towels and leave them lying on him: a towel resting on a dog traps heat instead of letting it go. Cooling happens en route. Do not delay leaving in order to cool him at home.

What heatstroke does after the panic passes is exactly why he needs to be admitted and watched rather than sent home. It injures the lining of the gut, the kidneys and the clotting system, and a dog who looks fine at hour two can bleed and crash at hour eight.

Learn the signs for next time: frantic panting, brick-red or dark gums, thick ropey drool, staggering, vomiting or diarrhoea that is sometimes bloody, then collapse. Flat-faced dogs, overweight dogs, thick-coated dogs, puppies and old dogs go down fastest, and humidity matters as much as the number on the thermometer.

Never leave a dog in a parked car. On a mild 22°C (72°F) day the inside climbs past 40°C (104°F) within the hour, and cracking a window changes almost nothing.