Shrews are among Britain's most abundant yet least understood mammals, with extremely high metabolic demands creating acute welfare vulnerability and an important role in terrestrial food chains.
Shrew welfare operates on razor-thin energy margins. An individual shrew that fails to find invertebrate prey for more than a few hours faces death from energy depletion. This makes habitat quality and invertebrate abundance directly life-or-death welfare determinants for every shrew in a population. Cat predation causes enormous numbers of shrew deaths annually - the play behaviour of cats kills without consumption, representing welfare harm for a very large number of individual animals for no ecological purpose. Shrews captured for study or rehabilitation die readily from handling stress, making them among the most fragile British mammals to encounter. The welfare lesson is that healthy soil invertebrate communities are the foundation of shrew welfare.