Wild Animals' Immune Systems Decline With Age, Sheep Study Finds

Researchers from the University of Edinburgh, Moredun Research Institute and Centre for Biodiversity Dynamics, Norway, made the discovery using blood samples taken from Soay sheep between 1990 and 2015. Analysis of more than 2,000 samples taken across the lifetime of almost 800 animals revealed that levels of antibodies against a common worm infecting the sheep fell in old age.