Road Less Traveled:
Satellite tracking of manatees is very revealing, because it lets scientists follow the movements of individual manatees, and learn where they migrate, how often, and under what conditions, and obtain important habitiat use information too.
But manatee tracking also leaves many unanswered questions too. And one of the most interesting asks what factors might influence why one manatee chooses to migrate to one area, while another manatee chooses somewhere else, and a third manatee still somewhere different? For example, compare the migrations of these two manatees on this animated map:
Compare Giffer and Anna's Migrations
As a starting point, biologist Susan Butler from the Sirenia Project explained that "we know that manatees act as individuals." One of the things that makes them individuals and influences their migration paths is the locations they learned previously in life, both as calf and an adult. "Depending upon sites they learned as calves and those added in their adult life, each manatee will show its own preferences," said Susan.
Once they've learned sites as a calf and adult, it is thought that habit also influences a manatee's migration choices. Susan notes "we do know that manatees are creatures of habit and they continually reinforce this thought." At the same time, manatees break habits just as we do, so Susan adds that "just when we think we have them figured out they will make some incredible move that will surprise us.
In the end, scientists may have to study this question for a long time, and still may never have a concrete answer. "We may never know the answer to this question but we still ponder it!!", said Susan. And with good reason. Knowing all the places where manatees migrate is important to preserving their habitat. As Susan said, Giffer's long distance migrations "are the kinds of movements that allow us to let the managers know that even though these animals were tagged at Port of the Islands they are traveling down to the southernmost Everglades and to the north (as far as Sarasota) as well. Most have stayed within the study area year round but we have had those animals that have left and then come back indicating that the SW in general is a very important area for manatees throughout the year. "
vs. Static Migration Maps
So, for the 2004 manatees that we're tracking, what does Susan think of their movements so far? Here are her comments:
"As far as the 3 females go, at this point their moves make sense to us because we have tracked them long enough to realize most of their patterns. It is still interesting to us that Leslie chooses the canal along US 41 during cold fronts, while the other 2 females choose POI.
"With the 2 new males we basically are starting from scratch. We know that manatees act as individuals and depending upon sites they learned as calves and those added in their adult life, each will show its own preferences. What is intriguing to us is who chooses to go where. Belvedere and Giffer are both larger males who obviously have existed in this area for several years. On the one hand Belvedere chooses to remain at Port of the Islands during cold fronts, while on the other hand Giffer chooses to travel quite a distance. We know that Giffer must have experience with the areas he has visited and is currently using because they are areas that are known for manatee use. "
National Geography Standards
World in Spatial Terms
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