Baby season update – EYNC Rattlesnake Study

Just a quick update on our reproductive females:

On Monday, 7 September, I found Female 53 missing from the hollow log where she had been gestating with Female 39, who was still present. This is the hollow log where I photographed a new baby on 6 September (see my last post) and I could glimpse youngsters deep inside the log again on the 7th. After considerable searching, I detected 53’s radio signal and followed it to a sycamore tree near the edge of the American River, 368 meters (402 yards) from where she had been. Since that day, she has moved a hundred meters or so back toward the oak woodland but has settled into a small cavity in the rocky riverbed.

This morning, 15 September, I found multiple shed “skins” from babies back at the hollow log and Female 39 was gone. I had checked the log yesterday and found no neonatal sheds.

Fresh neonatal shed "skin" (actually, the shed outer or "corneal" layer of the skin) in the log where Female 39 has been gestating since 14 June. — One of the neonatal shed “skins” (actually, just the outer or “corneal” layer of the skin) found this morning in the log where Female 39 has been gestating since 14 June.

Female 39’s radio signal led me to her 195 meters away, where she was coiled in dappled sun with lots of loose skin hanging on her. The babies shedding over the past 20 hours and the departure of Female 39 confirms that the kids were hers and were only a day or two old when discovered on 6 September (about 11 days between birth and the postpartum shed). Inspection of the inside of the log today with the BurrowCam revealed no rattlesnakes.

Then, when I checked Female 53 in her rocky riverbed hole this morning, she no longer appeared pregnant. In the BurrowCam video (link after the still photos below), look closely beyond her, just right of the center of the frame (next to the snail), beginning about 41 seconds into the clip. For the next 8 seconds, you can see a shiny wet baby moving behind her! I have circled the place to look in this still frame:

Female CROR 53 in streambed burrow Frame grab at 47 seconds into original BurrowCam video; 15 September 2016 — The place to look for the shiny moving baby in the video is circled in this still frame grab.

Also, compare the appearance of her abdomen in today’s video to her 3 September photo (in my last post).

Female CROR 53 in streambed burrow Frame grab at 57 seconds into original BurrowCam video; 15 September 2016 — Female CROR 53 in her streambed burrow at 52 seconds into the video clip. The violet sutures remaining from her May transmitter surgery are circled, indicating that we are looking at her posterior abdomen, which is no longer swollen.

Today’s 60-second BurrowCam video can be viewed on YouTube (click here).

Meanwhile, Female 75 remains in her burrow, still without kids, while Female 80 is still high on the bluff and inaccessible.

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