Operation Apefall
Operation Apefall was a theoretical British military operation, devised during the First Anglo-American War, which would supposedly employ the use of Macaques, specifically the Indian Rhesus, Bonnet, and Crab-Eating Macaques, to cause disruption to major American cities. Conceived in 2016, the plan was created by a former zoologist officer of the British Armed Forces in response to the shifting tides of the war, and the ability of the Americans to export their soldiers into the pacific, hoping to bring at least some of the American resources back inland.
After its conception in 2016, the proposal was considered by the Ministry of Defense, before being predictably turned down, but not without serious consideration. Later, in the beginning of the Second Anglo-American War in 2062, Operation Apefall was put on the desks of weapon designers and espionage specialists, who got as far as fully-functioning prototypes until the operation was canned, following the occupation of Hartford.
Methodology
Operation Apefall was to use two sources for their Macaques. The Rhesus species were to be covertly released from Morgan Island, South Carolina, which had a self-sustaining population of approximately 4,000 Rhesus Macaques. From there, they would occupy the nearby city of Beaufort, and would then be escorted by British spies posing as truckers to Charleston, the largest city in South Carolina. From which, it was theorized that interstate supply routes would handle the rest, and hopefully spread south to infest watermelon farms.
As for the Rhesus and Crab-eating Macaques, both species were to be released en-masse on cities in the east coast, most notably New York City, Philadelphia, Washington, and Miami. The sole intent of the Macaques was to be difficult to get rid of, and act as a thorn in the side of the U.S. government, requiring an immediate response, lest the problem continue.
During the revival of the idea in the 2060s, the Ministry of War requested designs for implementation of the plan. These concepts included a "seed bomb" design made to be parachute dropped by long-range bombers, or stored in fake backpacks, duffle bags, and cardboard boxes, which would each contain an individual Macaque, and a considerable supply of food. These cages would then be purposefully dropped in poorer areas, to avoid detection by police or residents, while still giving the monkeys an adequate source of food, usually in the form of food waste, other local pests, or wild plants growing undetected.