Question 9: When does a foal become a yearling? 问题9:成为周岁驹的年龄?
The first defecation we saw was in a yearling, a little 50-footer. 我们第一次看到蓝鲸排便，是一头一岁左右，约15米长的小鲸干的。
By contrast, in dry environments, the only long-term assemblages are a female and her offspring, sometimes just a foal, sometimes a foal and a yearling. 相反地，在乾燥环境下，唯一长期稳定的关系就只存在于雌马和子代之间，有时是一只马仔，有时是一只马仔加上刚满一岁的小马。
About 500 infective larvae were obtained and a yearling worm-free sheep was infected in Beijing. About 35 days post infection, the sheep began to deposit eggs from the feces. 其后作者又在当地采集了多量马歇尔属线虫的雌虫,取其虫卵,培养为第三期幼虫,在北京给一只绵羊进行了人工感染,并再次获得新种雄虫一条,因而确认为马歇尔线虫属的一个新种。