Animals grieve the loss of companions, and supporting them through bereavement is an important but often overlooked dimension of companion animal welfare.
Animal grief is now well-supported by behavioural evidence across many species. Companion animals that lose a long-term companion - whether another pet or a human - frequently show measurable behavioural changes consistent with grief: disrupted feeding, sleep changes, vocalisation, and searching behaviour. These responses are real welfare events, not anthropomorphic projection. Supporting a grieving pet requires patience: maintaining established routines provides security during disruption, increasing positive interactions and enrichment helps, and avoiding premature introduction of a new companion respects the animal's adjustment process. For social species like dogs and cats, the right new companion at the right time can eventually restore wellbeing - but the timing and introduction process matter greatly for both animals' welfare.