They expect subsequent generations of peninsular lizards will continue with hard-wired evolutionary changes in their physiology and behaviour – eventually a new form of the species may emerge, tailored to towards the hotter peninsula.Įven so, the authors do not distinguish whether the shifts in the characteristics of the peninsular lizards are genetically based, which would be a prerequisite for evolutionary change – the traits need to be heritable and passed on to subsequent generations. The authors conclude that a new environment rapidly selected the lizards that were best suited to survival. They found that in a warmer and more variable climate, those lizards that survived functioned better in the heat, were fast and were also active over a broad range of temperatures. The authors moved a population of brown anole lizards ( Anolis sagrei) from a forested site in the Bahamas to a nearby open peninsula where daily temperatures on the ground were more than 2☌ higher than the lizards were used to. Michael Logan from Dartmouth College in the US conducted a clever experiment with his colleagues to test whether tropical lizards have the potential to change their physiology over generations to better adapt to a warmer environment, but also one that is less predictable. Are species’ current tolerances and behaviours fixed – or can we expect scope for rapid evolutionary change through adaptation? Will some animals be saved by evolution? Speedy lizards This question of how animals might respond to a warmer and more variable world is the focus of a new study aimed at understanding how evolution might come into play as our climate changes. In a world of greater climatic extremes, lizards may over-expose themselves to dangerous temperatures, or may find themselves with only a few opportunities to feed or find mates if their activity patterns are constrained to a particular window in temperatures. Such behaviours that may be ill-suited to the increasing variability that is predicted with climate change where flexibility may be an asset. Species living in the tropics are also thought to have behavioural adaptations that are finely tuned to stable and predictable weather regimes, such as daily activity rhythms. Without the sweat glands or metabolic control that mammals take for granted, lizards can heat up very quickly if they find themselves caught out in the sun for too long. In particular, tropical species, including lizards, are thought to be especially vulnerable to climate warming because they already live at temperatures that can be dangerous. When it gets too hot, they can escape the heat by finding shade or retreating to burrows underground. Lizards seek out sunny patches or the warm underside of rocks where they can soak up the heat to enhance digestion or run faster. Lizards from the deserts of Australia to the tops of mountains in Costa Rica have given us insights into how animals take advantage of their environment to be less cold-blooded.

And yet it moves lizard