During the last two decades, eco-evolutionary studies have investigated the relevance of life-history traits and environmental conditions on telomeres of wildlife. Most of these studies have been conducted in endotherms, i.e. birds and mammals. They have provided evidence for the inheritance of telomere length; however, heritability estimates vary greatly within and among species. Age and telomere length often negatively correlate in vertebrates, but this decline is variable among taxa and linked to the method used for estimating telomere length. In contrast, the available information shows no sex differences in telomere length across vertebrates. Phylogeny and life history traits such as body size or the pace of life can also affect telomere dynamics. For example, it has been described across species of birds and mammals. In 2019, a meta-analysis confirmed that the exposure to stressors (e.g. pathogen infection, competition, reproductive effort and high activity level) was associated with shorter telomeres across different animal taxa.
Studies on ectotherms, and other non-mammalian organisms, show that there is no single universal model of telomere erosion; rather, there is wide variation in relevant dynamics across Metazoa, and even within smaller taxonomic groups these patterns appear diverse.