*This story illustrates how we identify individual snakes and how important these aggregation sites are to the rattlesnakes.
29 May 2010. One of the first snakes marked at this site was Zona, a female less than a year old when we first encountered her.
Zona was sitting on a downed log a few meters from two rookeries (where female rattlesnakes give birth to their young) and a den where many Arizona black rattlesnakes spend their winter. From the way she was positioned on the log, she was probably hunting for small lizards.  Zona was photographed and her rattle marked with purple paint so that she could be identified if we crossed paths again.
27 September 2010. That fall, Zona was one of the first rattlesnakes to return to the den. We found her on the opposite side of the den, stretched out along one of the large boulders. Only a tiny bit of purple paint remained on her rattle, but several aberrancies in her pattern confirmed who this little snake was.
Zona had nearly doubled in size over the intervening four months, but her dorsal blotches did not change in shape or number. Â We took a small sample of blood to determine her relatedness to other rattlesnakes at the den and wished her well.
April 2011. The rattlesnakes have just started basking at the den again and we’ve seen a few familiar faces, including Zona:
