The experience of a sense is particularly important in the case of pain. This chapter opens with naked mole rats, which can survive extreme conditions, such as living up to 18 minutes without oxygen.

The experience of pain depends on nociceptors, which are neurons; almost all animals have them, including naked mole rats. However, these animals do not seem to experience acids as painful. Thus, the chapter begins with the reality that pain is not experienced the same way across species. Pain, too, is subjective.

Nociception is the sensing of harmful stimuli without the sensation of pain. Nociception is the detection of damage, while pain is the suffering that often accompanies this detection. Nociception triggers a response before what is happening is consciously perceived; pain sometimes, but not always, follows this response. Pain is produced in the brain, while nociception occurs at the sight of damage and in the spinal cord. People generally do not separate the two but lump them together.

Pain is the sense that people often wish they did not have, and the distinction between nociception and pain is important for moral reasons. It is relevant to the design and procedures of experiments conducted on animals as well as to considerations of how animals are trapped, killed, or prepared for human consumption.