article_snippet.sent: A Western gray whale has made the longest known migration by any mammal.
article_snippet.sent: A Western gray whale (pictured) has made the longest known migration by any mammal. 
article_snippet.sent: Varvarva is now famous for making the longest migration of any mammal when Varvarva was aged nine.
article_snippet.sent: Varvarva journey is helping scientists make a surprising new discovery about migration patterns.
article_snippet.sent: The study said: ‘Varvarva 22,511 km round-trip is the longest documented mammal migration and strongly suggests that some presumed Western gray whales are actually Eastern gray whales foraging in areas historically attributed to Wester gray whales.
article_snippet.sent: The previous longest journey made by a mammal was held by a humpback whale, who swam more than 11,706 miles (18,839km) in 2011.
highlights_snippet.sent: Previous record was held by a humpback who swam 11,706 miles in 2011 .