The Greenland shark: a new challenge

21 The free radical theory of ageing predicts that long-lived species should be more 22 resistant to oxidative damage than short-lived species. Although many studies support 23 this theory, recent studies found notable exceptions that challenge the generality of this 24 theory. In this study, we have analysed the oxidative status of the Greenland shark 25 (Somniosus microcephalus), which has recently been found as the longest living 26 vertebrate animal known to science with a lifespan of at least 272 years. As compared to 27 other species, the Greenland shark had body mass-corrected values of muscle 28 glutathione peroxidase and red blood cells protein carbonyls (metric of protein oxidative 29 damage) above 75 percentile and below 25 percentile, respectively. None of the 30 biochemical metrics of oxidative status measured in either skeletal muscle or red blood 31 cells were correlated with maximum lifespan of species. We propose that the values of 32 metrics of oxidative status we measured might be linked to ecological features (e.g., 33 adaptation to cold waters and deep dives) of this shark species rather to its lifespan. 34 35