Wild animals in captivity are often kept solitary and isolated from conspecifics. Such conditions are stressful for species that are normally social, and have several detrimental effects on health and well-being. The impact of social isolation on cellular senescence or telomere length has not yet been studied in animals. Telomeres are the ends of chromosomes, which shorten with each cell division. Once a critical length is reached, cells are unable to further divide and enter a stage of ‘replicative senescence’. Telomere shortening has been shown to negatively affect individual health and longevity. Several studies suggest that exposure to chronic stress is a major cause in accelerated telomere shortening. To test whether social isolation affects telomere shortening, we conducted a cross-sectional study on a highly social bird species, the African Grey parrot. We compared the telomere lengths of single-housed versus pair-housed individuals. Our study population consisted of 45 parrots with widely differing ages (1-45 years). As expected telomere lengths were shorter in older birds. As predicted, we found that overall single-housed birds had shorter telomeres than pair- housed individuals. Comparable findings have been described in humans exposed to social deprivation, though our study is the first to examine the effect of complete isolation from conspecifics on telomere length in a bird species. Our findings support the hypothesis that social isolation results in reduced telomere length, and though the consequences on health and longevity are still debated, they suggest that telomere length may provide a biomarker for assessing exposure and ability to adapt to chronic social stress. To further confirm our findings, longitudinal studies measuring changes in telomere length over time in the same individual are needed.
telomere / African grey parrot / social deprivation / stress