Although cats’ popularity as pets rivals that of dogs, cats are little studied, and people's abilities to read this apparently ‘inscrutable’ species have attracted negligible research. To determine whether people can identify feline emotions from cats’ faces, participants (n = 6,329) each viewed 20 video clips of cats in carefully operationalised positively (n =10) or negatively valenced states (n = 10) (cross-factored with low and high activity levels). Obvious cues (eg open mouths or fully retracted ears) were eliminated. Participants’ average scores were low (11.85/20 correct), but overall above chance; furthermore, 13% of participants were individually significantly successful at identifying the valence of cats’ states (scoring ≥ 15/20 correct). Women were more successful at this task than men, and younger participants more successful than older, as were participants with professional feline (eg veterinary) experience. In contrast, personal contact with cats (eg pet-owning) had little effect. Cats in positive states were most likely to be correctly identified, particularly if active rather than inactive. People can thus infer cats’ affective states from subtle aspects of their facial expressions (although most find this challenging); and some individuals are very good at doing so. Understanding where such abilities come from, and precisely how cats’ expressions change with affective state, could potentially help pet owners, animal care staff and veterinarians optimise feline care and welfare.

People affect animals through four broad types of activity: (1) people keep companion, farm, laboratory and captive wild animals, often while using them for some purpose; (2) people cause deliberate harm to animals through activities such as slaughter, pest control, hunting, and toxicology testing; (3) people cause direct but unintended harm to animals through crop production, transportation, night-time lighting, and many other human activities; and (4) people harm animals indirectly by disturbing ecological systems and the processes of nature, for example by destroying habitat, introducing foreign species, and causing pollution and climate change. Each type of activity affects vast numbers of animals and raises different scientific and ethical challenges. In Type 1 activities (keeping animals), the challenge is to improve care, sometimes by finding options that benefit both people and animals. In Type 2 activities (deliberate harm), the challenge is to avoid compounding intentional harms with additional, unintended harms, such as animal suffering. For Type 3 and 4 activities, the challenges are to understand the unintended and indirect harms that people cause, to motivate people to recognise and avoid such harms, and to find less harmful ways of achieving human goals. With Type 4 activities, this may involve recognising commonalities between animal welfare, conservation and human well-being. Animal welfare science and animal ethics philosophy have traditionally focused on Type 1 and 2 activities. These fields need to include Type 3 and 4 activities, especially as they increase with human population growth.

To study animal welfare empirically we need an objective basis for deciding when an animal is suffering. Suffering includes a wide range ofunpleasant emotional states such as fear, boredom, pain, and hunger. Suffering has evolved as a mechanism for avoiding sources ofdanger and threats to fitness. Captive animals often suffer in situations in which they are prevented from doing something that they are highly motivated to do. The “price” an animal is prepared to pay to attain or to escape a situation is an index ofhow the animal “feels” about that situation. Withholding conditions or commodities for which an animal shows “inelastic demand” (i.e., for which it continues to work despite increasing costs) is very likely to cause suffering. In designing environments for animals in zoos, farms, and laboratories, priority should be given to features for which animals show inelastic demand. The care ofanimals can thereby be based on an objective, animal-centered assessment of their needs.