|Sharp-tailed snake showing the black-white crossbars underneath and spine on the tip of its tail.|
Recognizing a distinct black-white pattern helped me respond quickly to a little snake that appeared in the yard in April. Was this the newly described forest sharp-tailed snake? I immediately abandoned my yardwork and spent the rest of the afternoon playing citizen scientist.
The darn gophers like to tunnel along the low concrete wall in the front yard near my favorite birdbath. It's a gorgeous birdbath with a base shaped like overlapping lily leaves. I specifically placed that birdbath at that location in the front yard so I could watch the birds from the kitchen window while I cook and wash dishes. The gopher digging causes the birdbath to tip and spill its water, and eventually fall over. Someday, I'm afraid those gophers are going to break my favorite birdbath.
I was vengefully caving in the gopher tunnels underneath the birdbath in April when a small snake flipped out of the ground. I paused, quickly ran the brown/red color through my memory banks, dropped the shovel, and snatched up the snake. As I hoped, when I turned the drab captive over, it had a distinct belly side.
|The black ladder pattern underneath the sharp-tailed snake stands out.|
Since then, I've read that two species of sharp-tailed snakes are now recognized: the common sharp-tailed snake (Contia tenuis) and the forest sharp-tailed snake (Contia longicaudae). They look very similar but the later has a longer tail and is mostly found in coastal areas of California and Oregon.
One of the three locations where these two species occur in proximity to each other is San Mateo County of the Santa Cruz Mountains.
That's the location of the Dipper Ranch.
It's not clear if the range of the two species overlap, but they appear to prefer different habitats. Forest sharp-tailed snakes have been found in moist well-forested areas; common sharp-tailed snakes have been found in more dry and open grasslands, mixed woodland and chaparral.
The Dipper Ranch has both of these habitat types.
|Dipper Ranch in foreground has a mix of open grasslands, forested drainages and canyons and even some brushy slopes. Long Ridge in the background is mostly covered by continuous forest.|
If I carefully document the traits of each sharp-tailed snake I find on the Dipper Ranch to identify it to species, and if I note the geographic location and habitat type of each find, I might help further define the range of the two species in this part of the state.
Sounds like nerdy fun to me.
|The orange-brown stripes on the upper sides of this sharp-tailed snake (2013) were bright.|
Girls who handle snakes often have barbwire cuts on their fingers, dirt rubbed into their palms, and snaggy fingernails - that's just how we are.
To positively distinguish the two species of sharp-tailed snakes, you need to compare the total length of the snake to the tail length, count the number of scales on the underside of the tail, and measure in millimeters the width of the narrow black band versus white background on the belly scales (Feldman and Hoyer, 2010). This requires careful handling of the snake in order to get accurate counts and measurements. And to be nice to the snake. Between us two girls, the length measurements went smoothly but it was too hard to count the tiny scales or measure the black/white scale proportions on a squiggly live specimen, so I took numerous photos of the gently-held snake to look at more closely later.
|Sharp-tailed snakes may use the sharp spine at the tip of the tail to wedge themselves into the substrate while tugging out stubborn slugs for dinner.|
It wasn't until the next day that I had the time to enlarge the photos on the screen of my laptop and count the tiny tail scales. I was in a managers' meeting. After recounting numerous times, I determined there were either 47 or 48 tail scales. Checking Table 1 in the Feldman and Hoyer paper, that squarely put the April sharpie in the range of forest sharp-tailed snakes and outside the range of common sharp-tailed snakes, and it was also probably a female. I'm sure I probably uttered a little whoop in that meeting and it wasn't about the accounting software that was on the agenda. The rangers are used to ignoring me but I noticed the eyebrows of the Undercover Naturalist pop up.
|Caudal (tail) scales are to the right of the thumbnail indicator. The more anterior caudal scales do have some black blotches but they are not continuous bands across the entire width of the scale as with the ventral scales to the left.|
And it gave me a chance to talk about a few things about the snake that were not quite lining up. Based on measurements I took off my photos, the width of the black bands on the April sharpie were 40 to 50% of the belly scales. Some of the lit says forest sharp-tailed snakes have black bands one-fourth to one-third of each scale whereas common sharp-tailed snakes have thicker black ladder rungs underneath, one-third to one-half. Maybe my photos were too blurry to get a good measurement of this tiny feature. The Undercover Naturalist recommended it was time for me to finally get that macro lens. Feldman and Hoyer state that the black bands are usually absent from the tail scales of the forest long-tailed snake. The April sharpie showed black blotches on the tail scales but not continuous bands. What did that mean? I looked at photos on Cal-Herps of both species but just couldn't figure that feature out.
Also, I wasn't sure the distinct species habitat preferences described in the literature matched the conditions on the Dipper ground. The Dipper yard is mostly open grassland and dry in the summer although one side is lined by several large native big-leaf maple trees which surely predate the house. The Undercover Naturalist suggested I check my field notes and photos from the previous two Contias I found on the ranch. Even though I did not take any measurements for those snakes, maybe I could find some clues.
I found the first sharpie by the watertank on June 8, 2008.
|Handsome specimen for my first sharp-tailed snake June 8, 2008.|
|Although I didn't take any measurements in 2008, you can see the vent (dark line) in the lower part of the photo and the relatively long length of the tail after it.|
|I didn't take any measurements of this snake in 2011 and this is the only photo I took. I remember it as being small and lightly colored.|
|The Dipper farmyard where the April sharp-tailed snake was found is mostly open country although oak forests are close by. It is moist in the winter wet season and dry in the summer.|
common sharp-tailed snake, Contia tenuis
forest sharp-tailed snake, Contia longicaudae
- Robert C. Stebbins, Western Reptiles and Amphibians, Peterson Field Guide, 3rd edition, 2003.
- Alan St. John, Reptiles of the Northwest, Lone Pine Publishing, 2002.
- Chris R. Feldman and Richard F. Hoyer, A New Species of Snake in the Genus Contia (Squamata: Colubridae) from California and Oregon, Copeia 2010, No. 2, 254-267.
- California Herps