Telomeres are DNA-protein complexes that function as protective caps at the ends of chromosomes. Biologists and veterinarians at the Vetmeduni Vienna recently examined the telomere length of captive African grey parrots. They found that the telomere lengths of single parrots were shorter than those housed with a companion parrot, which supports the hypothesis that social stress can interfere with cellular aging and a particular type of DNA repair. It suggests that telomeres may provide a biomarker for assessing exposure to social stress. The findings have been published in the open access journal PLOS ONE.