SOME lizards escape predators by shedding their tail, but the experience appears to leave its mark. After losing their tail, lizards end up with damaging changes to their DNA.
The parts affected are the telomeres – stretches of DNA that cap the ends of chromosomes. Telomeres naturally shorten as cells divide, and shortened telomeres are associated in humans with the effects of ageing.
The shortened telomeres found in lizards that had lost their tail in a brush with a predator add to the evidence that environmental stress produces negative effects by eroding telomeres. The changes were observed by Mats Olsson of the University of Wollongong in New South Wales, Australia, and colleagues when they measured the telomeres of wild sand lizards, Lacerta agilis (Biology Letters, ).
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The team found that telomere length was especially affected in larger males, compared with females or smaller males. Olsson suggests that this is because larger males live more stressful lives than other lizards: they engage in more contests for female partners and are more likely to be attacked by predators.