you've seen your chimpanzees decrease in number かつて100万匹近く生息していたチンパンジーは 今世紀になって15万匹以下になってしまったし
furthermore , even after the spread of guns , bows and arrows remained in use even with a decrease in number , because arrows could be shot soundlessly regardless of the weather , and they could be shot quickly , and they were inexpensive , and furthermore , unlike the guns , hazuyari (the blade of a spear was attached to the tip of the bow , turning it into a spear in acute situations ) could be used , to a certain degree , to fight even in short-range battles . また、鉄砲が広まった後も天候に関係なく無音で射て、速射性に優れ安価である事、鉄砲と異なり弭槍（弓の先端に槍の穂を付け、緊急時に槍とするもの）で近距離でもある程度は対抗できるといった理由があるため、数を減らしながらも用いられ続けた。
