 Some animals , such as the horned lizards of North America , have evolved elaborate measures to eliminate shadow . Their bodies are flattened , with the sides thinning to an edge ; the animals habitually press their bodies to the ground ; and their sides are fringed with white scales which effectively hide and disrupt any remaining areas of shadow there may be under the edge of the body . The theory that the body shape of the horned lizards which live in open desert is adapted to minimise shadow is supported by the one species which lacks fringe scales , the <unk> horned lizard , which lives in rocky areas and resembles a rock . When this species is threatened , it makes itself look as much like a rock as possible by curving its back , emphasizing its three @-@ dimensional shape . Some species of butterflies , such as the speckled wood , <unk> <unk> , minimise their shadows when perched by closing the wings over their backs , aligning their bodies with the sun , and tilting to one side towards the sun , so that the shadow becomes a thin inconspicuous line rather than a broad patch . Similarly , some ground @-@ nesting birds including the European nightjar select a resting position facing the sun . The elimination of shadow was identified as a principle of military camouflage during the Second World War . 
