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The Action Tracker v.3.0

*You will need Flash (version 8 or higher) to view this movement visualization. To download the free Flash Player, click here.

    The Action Tracker is a novel tool that enables you to follow animals as they choose their path across the landscape. The Action Tracker takes animal location data and animates it as a sequence of points. We give you control over how to display the data. You can choose which individuals and species to look at, as well as the time period.

    These data can allow us to answer many different kinds of questions about why animals move as they do. How do different zebras vary in their movements? Do they always move at the same speed? Which habitats do zebras prefer? On the map, yellow is grassland. Shades of green represent woodland areas with increasingly dense bushes, mostly Acacia. You can compare pictures of grassland and woodland.

    Do you notice any differences in how zebras move during the day (6 am to 6 pm) versus at night? When do zebras go to drink? Notice that zebras are active throughout the day and night. Zebras' digestive system, which is known as hindgut fermentation, extracts energy rapidly, but requires them to continue grazing at night.

    We have found that plains zebras spend most of their time in the grassland. However, they shift toward greater use of woodland in the evening, as lions become more active. During the day, lions tend to rest in the woodland, while at night they hunt on the open plains. We think zebras may be using woodland more at night to avoid encounters with lions. Zebras also make more big moves at night, possibly to escape areas being used by lions.

    We now have two movement datasets. The default data you will see come from collars we put on zebras in Central Laikipia. These radiocollars have Global Positioning Systems (GPS) in them that record the individual’s position. From June 13-17 2007, we placed GPS collars on seven Grevy's zebra and two plains zebra. We caught seven individuals on Mpala Ranch and two on Loisaba Ranch. We can download data from the collars via a radio signal. Thus far, we have received data from two Grevy's zebra females whom we originally collared on Mpala.  As we collect it, we will display data from other zebras.

    For most of the month, the collar records a location once hourly. Between the 20th and 23rd days of each month, we have programmed the collars to take a fix every 15 minutes. This will allow us to look at zebras’ finer-scale responses to grass, water, predators, and each other.

    The second dataset you can examine come from Ol Pejeta Conservancy. These data come from June 24 until July 7 of 2005. The collars were programmed to take a fix every 8 minutes. We placed these collars on four plains zebra. The lion data come from our own sightings and those of Ol Pejeta staff. Plains zebras form long-lasting harems, which include a stallion male, several females, and their young. Three of the radiocollars from Ol Pejeta (PZ 8, 10, and 14) are females in different harems. PZ 6 is a bachelor. Bachelors often form close bonds with other bachelors. Herds form as harems associate with other harems and sometimes bachelor groups. Using the Action Tracker, do you see times when two or more individuals are moving together? How long do these associations last?

    You will notice that sometimes there are breaks in the line for an individual. This happens when there was a gap of more than an hour between two GPS fixes.

    Please check back again soon to track the zebras!

    The Action Tracker is © Heather Larkin, 2007. Please contact us to obtain permission if you wish to use the Action Tracker or any of the data displayed.

National Science Foundation - Special Report

The Secret Lives of Wild Animals -- Zebras

How do animals choose where to go on the landscape? See how we are piecing together zebras' decision-making process by observing their response to change.