Abstract
<jats:p>Postmortem Attentive Behaviour (PAB), in which individuals attend a deceased conspecific, has been documented across a range of mammals but rarely in pinnipeds. In harbour seals (Phoca vitulina), published observations are limited to three historical accounts. Here we report three new cases of PAB by female harbour seals on land and underwater. Behaviour was recorded opportunistically over three breeding seasons using trail cameras and drones. Females were observed attending dead pups for between two hours and four days, displaying behaviours including repeatedly transporting carcasses between land and water, retrieving them following displacement by waves, and maintaining prolonged physical contact despite advanced decomposition. These observations suggest that repeated carcass transport is a characteristic component of PAB in harbour seals and are consistent with similar reports from ice breeding seal species. Our observations highlight that PAB may influence wildlife monitoring by reducing the detectability and recoverability of dead pups. Maternal transport of carcasses has the potential to bias estimates of neonatal mortality and the sample of carcasses recovered through stranding programmes. We recommend that the potential occurrence of PAB be considered when designing pup monitoring protocols, carcass collection strategies, and ethical frameworks for wildlife health surveillance.</jats:p>