众所周知，人类和脯乳动物是用奶养子（仔）的。科学家通过研究发现，有些鸟、鱼、树竟也有奶。雏鸽孵化不久，老鸽的嗉囊中就开始出现一种白色的粥样物质，叫“嗉乳”或“鸟奶”。家鸽的嗉囊分泌“乳汁”期约为18d，此后，雏鸽就开始断奶，而野鸽的泌乳期要比家鸽长些，一般为 It is well known that humans and mammals are used as milk donors. Scientists have found through research that some birds, fish and trees actually have milk. Shortly after the young pigeon hatched, the white pigeon-like substance began to appear in the old pigeon’s pouch, called “milk” or “bird’s milk.” The pigeon’s bladder secretion “milk” period of about 18d, since then, the young pigeons began to weaning, and wild pigeons lactation longer than the average pigeon, usually