In Madagascar I watched male ring-tailed lemurs subjected to routine physical harassment – biting, shoving and hitting – to surrender their food, a cosy sleep spot or prime patch of sun. Like the sifakas, these stripy lemurs take their sunbathing very seriously – legs akimbo, arms outstretched and eyes rolling back in ecstasy as they soak up rays with the unashamed enthusiasm of a Brit in 1970s Benidorm.