Some sauropod dinosaurs had sensory afferent neurons over 50m in length. So if a sauropod accidentally touched a hot stove with its tail, it would take the brain over 25 seconds to realise it was burning itself (assuming C fibre conducting at 2 m/s). app.pan.pl/archive/publis… #pain Presumably evolution figured out a way of being quicker than this - perhaps by using fast myelinated A fibres or very fat C fibres for nociception instead.