STRIPE RECOGNITION
Each Grevy’s zebra has Unique Stripes
Just like humans have unique fingerprints, we use the stripes on Grevy’s zebra to identify individuals. The first people to develop this system were Hans and Ute Klingel. They would take photographs of the left side of Grevy’s zebra. They constructed their own dark room while out in the bush and developed several hundred rolls of films during any one field excursion. They then developed file cards for each zebra identified and would code the stripes. Using this unique coding system they were able to know which zebras they had seen for the first time and which they had “re-captured” in their camera lens.
With the development of the computer age, researchers began using computer programmes to identify Grevy’s zebra, but there were technical problems: the stripe pattern had to be coded by eye, which carried the risk of variation in interpretation through different observers. The code then had to be entered by hand, adding another layer of risk through typing errors. Additional information had to be entered into a separte database.
Digital Identification Software
The concept of a computer based program which individually identifies Grevy’s zebra by their unique stripe patterns was borne following discussions between Princeton University and Marwell Wildlife . Such a system would automatically compare photos of individuals to a database of previously recorded animals, thus saving researchers in the field weeks of manual work. It soon emerged that a system like this already existed, and was in the early stages of development with Conservation Research Ltd.
How Stripe Patterns are Extracted
The stripe ID software uses a 3-dimensional model to fit a generic body shape to the photo. In the case of Grevy’s zebra the system applies the model of a zebra to the photo and takes into account the different positions of the animal. Posture and fattening & thinning of the animal (e.g. during pregnancy) are accounted for.
Take part in our Grevy's zebra identification project!
Have you seen Grevy’s zebra in Kenya? If you have, we would love your photographs! You can email your photos to us along with the following information for each image:
- Date of sighting
- Location of sighting
- Sex of the Grevy's zebra if known
- GPS coordinates (latitude/longitude) if available
If you are planning a trip to Kenya and might be going to areas where Grevy’s zebra are found and would like to contribute your photos to our photo-identification project, please photograph the zebra from the side as in the example below:
Please send your photos and associated information to conservation@grevyszebratrust.org
Thank you for helping us with this important project!
How does this ‘fingerprinting’ process help Grevy’s zebra?
Members of the Grevy's Zebra Technical Committee have decided to establish a centralised database where each member contributes their photographs and associated life history information. The database will provide critical information to scientists and managers for planning future conservation action. Here are two examples of how this data can advise conservation:
- Population vital rates
We can track the fates of individual zebra across a broader range. From this shared data, we can improve our ability to estimate key population vital rates such as movement, reproduction and survival.
- Population movements
From repeated observations of an individual we can determine the extent to which movement occurs across different population units. From this we can then identify critical population corridors or barriers.
