Migration Update: March 31, 2004
Field Notes from Susan Butler: Tracking Trouble?
Have we got a lot to report this week! First, while Jim Reid was in the field earlier this month, he not only got visual sightings ("visuals") on all of the tagged manatees (except Actual), he also replaced the floating transmitter tags on two of the manatees, Anna and Giffer. They both had PTT's (Argos satellite tags) and Jim switched them to the newer GPS (Global Positioning) tags. Do you know what the difference is between these two types of tags, and which will give us more accurate locations? How would a scientist "change tags" on a manatee in the ocean? Read on!
Second, we've seen some big moves by a manatee that hasn't moved much this season. Take a look at today's data and maps. Can you figure out which manatee has been "on the move"? (Hint: Look north!)
Reason to Worry? The Search is On
Do you have any ideas why? What things could possibly cause manatee tracking signals to stop or be interrupted? And how do you think we would try searching for Anna and Actual now that we are not receiving any satellite data? Take a minute to get all the details below about the tags and other equipment used to track manatees, and then come back to see if you can answer these Challenge Questions. While you're doing that, we'll be out in the field keeping watch for Anna and Actual, and we will update you soon.
to Latest Data and Individual Manatee Maps:
now, we're headed back out on the water!
Manatee Habitat--Why Leave the "Mother of All Seagrass Beds"?
In our last report, we learned that in the Spring manatees are attracted "offshore" to the food-rich sea grass beds and warm waters of places like Cape Romano and the outer islands of TTI. But we still see the manatees leaving this lush habitat and returning regularly all the way inland to places like Port of the Islands, the inland creeks, and the canals, especially in the dry season, when there is less rainwater and runoff. Why do they still leave the offshore areas and come inland like this?
Get a better taste for this topic below, and then try the Journaling Questions that follow:
Try This! Journaling Questions:
Manatees have so many unique adaptations--just think of the features of their head:
Can you imagine having all these characteristics yourself? Find out more about these adaptations:
A Conveyor Belt of Teeth
look and listen to a manatee munching in this lesson and video clip:
This! Journaling Question:
Manatee Math: You Eat How Much Each Day?
Could you ever imagine eating 50 pounds of food in a day? How about 75 pounds of food? For a manatee, that's no problem. The manatee's appetite is really remarkable.
Manatees maintain their giant size by feeding primarily on seagrass. Lots of seagrass--between 10% to 15% of their own weight everyday!
Answers from the Manatee Expert
You really came up with some great questions like "how fast does a manatee swim?", and "Are they really related to elephants?"
Did you stump Nancy or was she able to meet your challenge?
About Journey North Species
How to Respond to Today's Challenge Questions:
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The Next Manatee Migration Update Will Be Posted on April 7, 2004.
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