Being caught by a large human can be stressful for a lizard, which means if we need a blood sample, we have to catch the lizard within a short time of their spotting us. This way we’re sure to capture their “baseline” hormone levels rather than the levels induced by a scary human leering at it. The blood samples we need to test the latitudinal cline with stress hormones that I described in my previous post all have to be collected within 2 minutes for this reason. Sometimes this is a difficult process! Here’s Sean catching a sneaky little lizard in Alabama. (Sorry for the shaky-cam! I couldn’t get too close for fear of scaring away the lizard.)
Relatively soon after collection, we have to spin down blood samples in a centrifuge in order to separate out and draw off the plasma, which contains the hormones. We have a handy dandy field centrifuge, but we’ll take power where we can get it!
The next step is to run assays on these plasma samples. We frequently run CORT assays in the lab (remember this?), so hopefully we’ll have this data soon!