Manatee Manatee
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Manatee Migration Update: March 31, 2004

Today's Report Includes:

Field Notes from Susan Butler: Tracking Trouble?

Hi Students,

Latest "All Manatee" Migration Map
Click on Map to Enlarge

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!)

Any Reason to Worry? The Search is On
Third, do you also notice that there has been no location data for two of the manatees in recent weeks, Anna and Actual? We have not received any data from them since the evening of Saturday March 13.

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.

Challenge Question #15:
"What do you think are the possible reasons that no data is being received from Anna's and Actual's tracking tags?"

Challenge Question #16:
"If you were in the field with Susan, how would you try to locate Anna and Actual now that we are not receiving any satellite data from them?"

(To respond to these questions, please follow the instructions below.)

Link to Latest Data and Individual Manatee Maps:
(Courtesy of U.S. Geological Survey's Sirenia Project)

Bye for now, we're headed back out on the water!

Susan Butler
Sirenia Project

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:


Credit: USGS-Sirenia

Try This! Journaling Questions:

1) If manatees are in warmer water eating abundant seagrass offshore, then why do you think they would bother to go all the way back inland? Doesn't it seem like they have everything they need in their offshore habitat? (Hint-remember they are mammals like you.)

2) Why would manatees return to inland waterways more often during the dry season than the rainy season?

Amazing Adaptations
Manatees have so many unique adaptations--just think of the features of their head:

  • Lips that move as several separate parts
  • "Fingers" on the face?
  • Nostrils that close tight like valves
  • New teeth all the time--a lifetime supply

Can you imagine having all these characteristics yourself? Find out more about these adaptations:

A Conveyor Belt of Teeth

Did you know?
Manatees are also referred to as
"Sea Cows"

The mouth of a manatee has so many interesting features. And "Marching Molars" are just the beginning. But that's not really a big surprise--especially when you consider how much food a manatee eats everyday --you'd probably need some special features in your mouth too!

Stop, look and listen to a manatee munching in this lesson and video clip:

Photo Credit: FWC, Audio/Video Credit: SMC, International Film Projects,Inc

Then "open wide" and bite into this Journaling Question:

Try This! Journaling Question:
How does tooth loss and replacement in a manatee's mouth compare to the way your teeth are lost and replaced? What dental problems do "Marching Molars" solve for manatees? Do humans have the same problem? How do you solve it?

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!

Hungry for a Challenge Question?:

Challenge Question #17:
A) If a Manatee eats between 10% to 15% of its body weight each day, how many pounds (or kg) of food would that be for a 1,000 pound manatee?
B) Now let's talk pizza! An average thin crust frozen pizza weighs about a pound. How much do you weigh? How many pizzas would you have to eat in one day to equal 10% to 15% of your body weight?"

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?

Link to Answers from the Expert
Credit: FWC

FAQ's About Journey North Species
Since 1995, experts have contributed answers to students' questions about each Journey North species. These questions and answers are archived in our FAQ's (Frequently Asked Questions) section. You can use today's Answers from the Expert, along with those from previous years, in the activities suggested in the lesson, "FAQ's About Journey North Species".
See: How to Use Journey North's FAQ's

How to Respond to Today's Challenge Questions:

IMPORTANT: Answer only ONE question in each e-mail message.

1. Address an e-mail message to:

2. In the Subject Line of your message write: Challenge Question #15, (OR #16 OR #17)

3. In the body of EACH message, give your answer to ONE of the questions above.

The Next Manatee Migration Update Will Be Posted on April 7, 2004.


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