1、The castor is a semi-aquatic mammal commonly found in North America and Europe.
海獭是一种常见于北美和欧洲的半水生哺乳动物。

2、Castors have a double-layered coat that protects them from the cold waters.
水獭有一层双层的毛皮，可以保护它们不受寒冷水域的影响。