求翻译：　　海鲸为了摄食和繁殖，许多大型的灰鲸会定期的迁移。冬季的时候待在渔产丰富的两极地区，夏季的时候就迁居到热带海洋避寒和繁殖。灰鲸这么长距离的迁移但却不会迷路，他们靠什么来辨别方向呢？原来，灰鲸靠海岸线、地球磁场、太阳的引力和潮汐的关系，甚至每一个海湾和河流不同的味道都可帮助他们，以免迷路。是什么意思？

Whales to the feeding and reproduction, many large gray whales regularly migration. Winter when the stay in the fish-rich polar regions in summer, when moved to the tropical marine refuge from the cold and reproduction. That distance to the gray whale migration but will not get lost, they rely on to

Sea whale feeding and breeding grounds for many of the large, gray whales migrate regularly. In the winter time when fish rich in both polar regions and in the summer the time moved on to the tropical refuge from the sea and breeding. Gray whales migrate so long but don't get lost, and what do they

　　The sea whale in order to take in food with the reproduction, many large-scale greybacks meet the regular migration.Winter when waits produces the rich two-pole area in the fishing, summer time moves to the tropics sea evades cold and the reproduction.But the greyback such long distance migration

　　Sea whales for feeding and breeding, many large grey whale migration on a regular basis. When the fish rich in polar regions during the winter, when moved to the Tropical Ocean to avoid the cold in the summer and reproduce. Migration of gray whales so long but it will not get lost, they live on to