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The
Road Less Traveled:
Why Does One Manatee Migrate to One Place,
While Another Goes Elsewhere?
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
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| Click on map to enlarge. |
| "The
question for us as biologists is 'what makes these animals make such different choices??'" Susan Butler |
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. "
Journaling Questions
Animated
vs. Static Migration Maps
Using an animated tracking map like the one for Giffer and Anna above
can be very helpful. But do you think that an animated map is always better
than a static map? Try these journaling questions and decide for yourself.
1) Look at the animated map. Write out a list of what information it gives or shows you. Make the same list for a static map and for a chart of latitude/longitude data. Is there information found in one map that is not available in the other or in the data chart? Compare and explain.
2) Now that you've compared the maps and data charts, if you were a scientist, how many of these would you like to have in your work? Could you do your work and studies fully and thoroughly if you only had one? or two? Explain you answer.
3) Compare the manatee animated migration map to the animated migration maps for monarch butterflies and caribou. Explain the difference between what is shown in each.
Journaling
Questions--Comparisons
To
investigate questions, theories and ideas, scientists sometime compare
the situation they are studying to another situation. Can you compare
your travels to a manatee's?
(a) Think about you and your friends and your neighborhoods. Why reasons might make you decide to go to one playground, grocery store, restaurant or movie theater, while your friends might go to different ones? How do the reasons that guide you compare to manatees'? Discuss this with your classmates, and write your ideas in your journal.
(b) What about when you're in an unfamiliar city, like when you are on vacation. Are the reasons for your decisions different when you are in unfamiliar territory for the first time? What about if you come back to that city a second time, and it is no longer totally unfamiliar? How do you think a manatee makes choices in unfamiliar territory? Discuss this with your classmates and write your ideas in your journal.
(c) Ask adults how they make these choices, such as your parents, teachers, brothers, sisters, grandparents.
"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. "
The
World in Spatial Terms
How to use maps and other geographic representations, tools, and technologies
to acquire, process, and report information.
Copyright
2003-2004 Journey North. All Rights Reserved.
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