Perhaps some of you may enjoy seeing photos of a fine diamondback that
I almost stepped on yesterday. Apologies to those who have seen this
already.
The sighting provoked a comment from Paul Moler, herper extraordinaire, who
somewhat jokingly suggested that being venomous was the one shared
characteristic among the few reptile species not in catastrophic decline here in
north Florida. I answered that it was prey choice, and thus exposure to
ranavirus. See below:
So there I was being super surreptitious as I scouted a way through the
palmettos when I looked down by my foot and saw this.
That's about a four and a half foot Diamondback rattler. My foot was about
six inches from it's nose when I went airborne. Worse still, I had been standing
there fidgeting around for several minutes trying to find my way past a Lyonia
thicket so the nipper had lots of reasons to get riled up but didn't.
Notice the "please don't step on me" posture with the head drawn back in a
hook. Totally passive defense. That is because it knew that I hadn't seen it, I
was just another clumsy klutz to be avoided, no need to waste valuable
venom.
So I retreated about thirty feet away and watched. As soon as I appeared to
be gone Mr. Nipper started to rapidly crawl in the opposite direction. When I
approached again it was obvious that I wasn't an innocent bystander so pretense
was put aside and it was time to coil and rattle.
Such forbearance! If rattlesnakes were even one hundredth as mean as people
imagine them to be then I wouldn't be sitting here drinking a beer and writing
this story.
This incident occurred while I was scouting and chopping Weazel Way South
just south of the Gainesville Hawthorn trail and not far west of Prairie creek.
This is the forth rattler I have found while chopping Weazel Way so step lively
out there!
SW
Sleaze:
But you said there weren't any more snakes out there. I took you at
your word and started going barefoot. That was, until Thanksgiving day when I
saw a deadly coral snake in woods along the Santa Fe. And a couple of weeks ago
a red-shouldered hawk flew over my drive carrying a ground rattler. Maybe it's
just the non-venomous serpents that have disappeared.
Paul
Moler
Florida Fish & Wildlife Conservation Commission
1105 SW
Williston Road
Gainesville FL 32601
(352) 334-4217
Paul:
It is not a matter of being venomous, it is a matter of what you eat.
Rattlesnakes eat warm blooded prey that don't carry ranavirus. Coral snakes eat
tiny reptiles such as ground skinks that never eat frogs. They might well eat a
young natricine but it is entirely possible that said young natricine has not
yet had a chance to become infected by ranavirus; whereas if you were a
kingsnake that routinely eats adult natricines it is inevitable that you will
get infected and die.
Green snakes, which eat bugs but not frogs, are still out there.
Redbellies, which specialize on slugs and worms, are still out there too.
Ringnecks which eat salamanders have gotten relatively scarce.
Ratsnakes are a curious case. I have had great difficulty getting neonates
to accept pinky mice. They seem to want something else, perhaps frogs and
lizards, though a small percentage readily accept pinkies. As adults they
exclusively eat warm blooded prey and thus have no contact with ranavirus. That
would explain the disparity in the ratio of adults to young that I have
observed. In the bad old days I often found baby ratsnakes, now it is mostly
adults. Cornsnakes are a different story. Once common everywhere, they now seem
to persist mostly in urban areas. Is it possible that young cornsnakes are more
likely to eat frogs than young ratsnakes? I don't know. Do you?
As for the frogs, you will notice that hylids have made a fair comeback
this year. That isn't just because it rained this year, it is because they breed
in temporary ponds that have been dried up for several years, thus killing the
pathogens. Frogs that breed in permanent or semipermanent wetlands aren't doing
so well, perhaps because bullfrogs, which appear to be partially
immune, serve as reservoirs for the disease.
As for moccasins, damn if I know. They seem to be immune to everything,
even rednecks!
I don't know how long ranavirus can persist in a
moist environment, or how long infected animals remain infectious, but an
unintended experiment is underway. As you may remember, my turtle pen is in a
warm moist environment with trees, dense vegetation, deep humus, and a fairly
large pond with deep sediment and Gambusia. The conditions are very natural
though perhaps a bit too shaded, good for box turtles but not baskers.
About ten years ago all but two of my turtles died during what I presume
was a ranavirus epidemic, the most notable symptom being that their feet rotted
off. An adult Terrapene carolina major and a Cuora amboinensis were both
infected but recovered and are alive today. The pond was never cleaned in any
way, and bullfrogs come and go at will. The bullfrogs never died out even during
the height of the epidemic, though they have declined since in regard to both
size and number.
As an experiment, about three years after the epidemic I introduced a
box turtle from northern Alabama. It was dead within a month.
This spring someone placed two adult redbellies (Pseudemys nelsoni) in the
pond without my permission. They were obviously someone's pets as they were
quite tame. They have thrived thus far, though with the onset of cold weather
their behavior is more difficult to observe. If they make it through till spring
I will tentatively conclude that the epidemic has finally run its course and
that the two previously infected turtles may still be carriers but are no longer
actively infectious.
We need to know how ranavirus persists in the environment. Does it persist
in moist or wet sediment? Or does it persist in previously infected animals? I
think we need to look more closely at bullfrogs and fish. Gambusia are
omnipresent and do not seem to be affected, could they be carriers?
SW