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
Dazzle camouflage the Animal Kingdom". Seeing the opportunity to put his theory into service, Thayer wrote to Churchill in February 1915, proposing to camouflage submarines by countershading them like fish such as mackerel, and advocating painting ships white to make them invisible. His ideas were considered by the Admiralty, but rejected along with Kerr's proposals as being "freak methods of painting ships ... of academic interest but not of practical advantage". The Admiralty noted that the required camouflage would vary depending on the light, the changing colours of sea and sky, the time of day, and the angle of the sun. Thayer