Camouflage there is no background, the principal methods of camouflage are transparency, silvering, and countershading, while the ability to produce light is among other things used for counter-illumination on the undersides of cephalopods such as squid. Some animals, such as chameleons and octopuses, are capable of actively changing their skin pattern and colours, whether for camouflage or for signalling. It is possible that some plants use camouflage to evade being eaten by herbivores. Military camouflage was spurred by the increasing range and accuracy of firearms in the 19th century. In particular the replacement of the inaccurate musket with the rifle made
Military camouflage with magnetic sensors. Horizontal coils around the whole or parts of the ship generate magnetic fields to "cancel out" distortions to the earth's magnetic field created by the ship. Ship camouflage was occasionally used in ancient times. Vegetius wrote in the 4th century that "Venetian blue" (bluish-green, like the sea) was used for camouflage in the years 56–54 BC during the Gallic Wars, when Julius Caesar sent his scout ships to gather intelligence along the coast of Britain. The bluish-green scout ships carried sailors and marines dressed in the same colour. The emphasis on hand-to-hand combat, and the short range