that such counter-illumination camouflage was possible, arousing interest in both Britain and America, but the equipment was cumbersome and fragile, and neither the Royal Canadian Navy nor their allies brought it into production. Active camouflage in animals An equivalent active camouflage strategy, known to zoologists as counter-illumination, is used by many marine organisms, including fish, shrimps, and cephalopods such as the midwater squid, Abralia veranyi. The underside is covered with small photophores, organs that produce light. The squid varies the intensity of the light according to the brightness of the sea surface far above, providing effective camouflage by painting out the animal's silhouette with light. US Navy research project Goal Yehudi lights were developed by the US Navy to help counter the "menace" of German submarines to Allied shipping in the North Atlantic. The United States Army Air Force's Director Of Technical Services (DTS) asked the camouflage section of the National Defence Research Committee (NDRC) to develop a camouflage method that would allow a radar-equipped, sea-search aircraft to approach a surfaced submarine to within 30 seconds' flight time before being seen. This was to enable the aircraft to drop its depth charges before the submarine could dive. British researchers had found that the amount of electrical power required to camouflage an aircraft's underside in daylight was prohibitive; and that externally mounted light projectors (following the Canadian approach) unacceptably disturbed the aircraft's aerodynamics. The DTS, and through him the NDRC, were informed, in line with the Canadian findings, that even a white aircraft would normally appear dark against the sky. They were further told that while "floodlighting" the aircraft (in the manner of diffused lighting camouflage for ships) could in theory make it bright enough to match its background, that would require an impossibly large amount of electrical power: but a less power-hungry option was available, namely to use forward-facing lights, and to require the aircraft to fly within 3 degrees of the line directly towards the submarine, so that only its counter-illuminated front would face the enemy. Pilots noted that if they chose a straight-line heading to compensate for a crosswind, the nose of the plane would not point directly at the enemy, but could be, say, 20 degrees off. Since making the beams bright enough at such a wide angle was impracticable, pilots were instructed to keep the nose pointed directly towards the target at all times, resulting in