NANFA-- Battle of the Titans

Denkhaus, Robert (DenkhaR_at_Ci.Fort-Worth.TX.US)
Sat, 2 Dec 2000 10:39:41 -0600

I had a few minutes to get out of the office yesterday and decided to see
what interesting critters could be dip netted out of one of the small bays
on Lake Worth along the Fort Worth Nature Center & Refuge's southern border.
Caught a freckled madtom, a number of small sunfish and a bushel of Gambusia
and glass shrimp. The only unusual capture was a small (quarter-sized)
razorbacked musk turtle (Sternotherus carinatus). Deciding that the little
guy would make a good to our turtles on display, I tossed him in the
collection bucket.

Upon return to the Interpretive Center, I decided to temporarily put the
little turtle in the 55 that I keep in my office. I use this tank to hold
fish temporarily, observe new critters, house future foods, and generally
amuse myself when I should be working. It contains an eclectic group of
organisms that tends to change with the seasons.

About an hour after I had dropped the turtle into the tank, I noticed a
flurry of activity and found that a Predacious Diving Beetle (Cybister spp.)
that has inhabited the tank since the spring was attacking the turtle. The
beetle, also about the size of a quarter, had latched on to the turtle's
left rear leg and was violently trying to flip the turtle over onto its
back. The turtle was stretching its neck as far as possible in an attempt
to get a hold on the beetle while also using its free legs to flee the area.
The tenacious beetle, which are also called water tigers, refused to let go
for several minutes but finally released the turtle and shot up to the
surface, apparently for air. The turtle, taking advantage of the
opportunity, made a mad dash for some plant and rock cover. After getting a
breath of air, the beetle immediately dove and returned to the site of the
attack. Finding the turtle gone, the beetle went into search mode and began
quartering the tank bottom just like a bird dog searching for quail. Two
hours later, the turtle was still in hiding (although he made a couple of
stealthy trips to the surface for air), the beetle appeared to have given up
the hunt, and I left for home believing that the battle was over. WRONG!

When I got to work this morning, I found the turtle out in the open, dead.
The carcass looked like it had been mauled by a pack of wolves. I never
would have believed that the beetle could have been the culprit if I hadn't
seen the beginning of the battle yesterday. Has anyone else ever witnessed
anything like this?

Rob Denkhaus
Fort Worth Nature Center & Refuge

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