9 December 2014

12:58 PM; 100% thick low overcast, 15C (59F), everything is wet in between two significant rain events.

I heard the sound of a wet rattle rattling at the log where four of our telemetered snakes are located and found a small unmarked male in the new green grass – CROR44 (I’ll explain “CROR” below).  This snake is small at 638 mm (25 inches) and 141 g (5 ounces) but has a broken rattle with only two segments.Coo44 rattle 100dpi_4x6 Upon closer examination, this little guy was found to have some fresh and significant trauma to his posterior abdomen and tail area, including a deep penetrating wound at his cloaca (derived from the Latin word for sewer, the cloaca is the single vent that empties the digestive, urinary, and reproductive tracts in lower vertebrates). Since this rattlesnake was about the same size as the unmarked snake I saw but didn’t capture at this log on 15 November (see photo of tail in 2014 Update #13), I compared scale markings on the tail with the photograph and concluded that this is the same rattlesnake. Sometime in the past three weeks, something got a hold of this snake before he could get all the way under the log and injured him severely, as well as pulling off most of his rattle (the rattles are hollow, brittle and easily damaged). Since my study intends to observe and document natural occurrences (and my permits do not authorize interference in the natural processes), I measured and marked this injured snake (no transmitter surgery) and released him under the log. I am doubtful, however, that he will survive, as his abdominal wound looks deep and they do not heal well when they are cold (e.g., over the winter).

After checking on all of the other telemetered rattlesnakes (none had moved recently), I checked on male #37 on the hillside and found only static at his radio frequency. Given the time of year, the cool weather, and the fact that all other snakes seem to be down for the winter, it is hard to imagine that anything has happened to him. His transmitter has simply failed prematurely, just as the radio in male #36 did a few weeks ago. This is not a common occurance but tends to affect multiple transmitters when it does occur because they were often refurbished from the same batch of batteries. Like male #36, we can only hope to find him in the spring, either around the buildings or courting a telemetered female. I think there’s a good chance of that, though.

An explanation of CROR: Taxonomists and other biologists, at least in the herpetology field, seem to be moving away from the subspecies concept. In giving study animals identifying monikers, we have long used the initials of the genus, species, and subspecies names, plus a number. Thus “Coo36” would be Crotalus (the genus) oreganus (the species) oreganus (the subspecies) number 36 (if he were a southern Pacific rattlesnake, he would be Coh36 for Crotalus oreganus helleri). As taxonomists continue to either lump subspecies together or elevate them to full species status, the numbering convention had to change. So now we are using the first two letters of the genus and the first two letters of the species, so Crotalus oreganus #36 becomes CROR36!

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