When you find snake eggs . . .
In July, Sperryville resident Virginie Audrain sent me some photos of eggs she and her companion, stonemason Jim Carter, found in one of the compost piles they use to fertilize their gardens.
Virginie, who is still recovering from the terrible automobile accident she had in January, has been spending a lot of time gardening and enjoying the recuperative powers of nature, she says. She had contacted me last year, before the accident, to report seeing a snapping turtle laying eggs in one of her flower gardens. She patiently kept an eye on the spot, but no baby snappers ever emerged.
Virginie was hoping to have better luck with the 24 reptile eggs she and Jim found this year, within days of when the eggs were laid. She described them in her email:
“They have a weird texture, compared to chicken eggs . . . . The turtle eggs were looking round like a golf ball. We are thinking snakes, but what kind?”
The eggs in the photos definitely looked like those of a snake — and a large one. One way to tell snake eggs from those of a turtle are the former’s oblong, soft but leathery shell. Considering where the eggs are formed (inside the snake’s elongated, narrow uterus) and how the snake moves (slithering along the ground), the shape and soft shell are good adaptations. Turtle egg shells are harder and generally smaller relatively speaking, because they have to pass through a narrow gap between the upper and lower shells of the female.
While the eggs Virginie and Jim found were mottled, one of the two herp experts I contacted about the eggs reminded me that most reptile eggs are white or cream, and mottling usually comes from the substrate in which they are laid (compost in this case). I remembered that the same issue had come up when my landlord found the eggs of a lizard, a five-lined skink, under a board, which I wrote about in my July 23, 2015, column. It stands to reason these snakes and lizards would not need to camouflage their eggs, like many birds do, because their eggs are hidden.
In trying to figure out which snake species had laid the eggs, the one thing I did know was that the eggs were not from our area’s two venomous snake species, both pit vipers — the northern copperhead or the eastern timber rattlesnake. Both of these species give birth to live young. They gestate the eggs, which only have a clear membrane rather than a shell, inside their bodies. The eggs also didn’t come from a northern watersnake, a harmless species that Virginie had reported seeing near the house, because it, too, gives birth to live young rather than eggs.
The herp experts further narrowed the field to a northern black racer (Coluber constrictor constrictor), red cornsnake (Pantherophis guttatus) or eastern ratsnake (Pantherophis
alleghaniensis). The latter two are in the same genus and have similar-sized eggs (1-2 inches in length). My vote was for the ratsnake because there are so common in our area, and Virginie later told me that they had seen ratsnakes on the property but not black racers or cornsnakes. Racers lay their eggs earlier in the year, so they were also ruled out.
To help save the eggs, I suggested Virginie and Jim make a smaller compost pile away from their garden area and transfer the eggs into that. Having a slow internet connection, Virginie is not online that much, and I was hugely busy when she contacted me, so email was going slowly both ways. She eventually wrote to say she noticed the new pile with the eggs looked a bit dried out and wrote that she had not thought to hydrate it.
I had also not thought about hydration for the eggs, so hadn’t suggested it but should have. Snake eggs are produced with little fluid in them, to keep the volume of the eggs small and manageable before they are laid. Once laid, the eggs absorb water needed for the embryos’ development from the substrate through their leathery, highly permeable shells.
Eastern ratsnakes, with which I have the most experience, primarily from my hanging around stables as a kid, love a soft, damp — but not wet — substrate, such as manure, sawdust or compost. In reading up on cornsnakes, I found they prefer similar sites for their eggs.
I didn’t get a chance to follow up on the status of the eggs until mid-September, at which point the hatching of eastern ratsnakes is typically underway, lasting through mid-October. I visited Virginie, who showed me the compost pile to which she and Jim had transferred the eggs. It was pretty small and shallow, and I thought that it might not have protected the eggs from the high summer heat and a recent dry spell, and even from too much water from some pretty torrential storms this summer.
In poking around in the pile, I discovered the eggs just below the surface, definitely not viable and showing signs of being fed on by invertebrates and fungi. It looked like they’d been that way for some time, so it’s not clear exactly why they didn’t survive. Finding snake eggs was a new situation for Virginie, and for me, but we both learned from it. With plenty of eastern ratsnakes and red cornsnakes around, it likely won’t be the last time she and Jim find similar eggs in their compost.