How powerful...?

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black_sun

Fire Eel
MFK Member
Jul 31, 2008
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New Jersey
How powerful is the bite of a Polypterus? (If it depends on the species, amend the question to Polypterus senegalus)

I was just watching my Poly stalk a goldfish and bite it. Unfortunately, the fish turned out to be a little too big for the Poly to swallow so it went off and ate a different fish instead. However, the first fish it attacked was very injured by the bite. It appeared to have had it's spine broken, as it's body was doubled over and incapable of moving into another position. The fish could still swish it's tail and the fins on one side a little bit, but nothing else. I took it out and gave it to my crays so it wasn't lingering.

But it really made me wonder about the power in that little Poly's bite and uh, slightly paranoid for the next time I need to vacuum the substrate in my tank. It likes to investigate my hand and the vacuum at little too intently, hah. But really, is it really a strong bite or are goldfish's bones that easy to break?
 
Polypterid bite force
The mechanics of jaw closing are highly variable in
basal actinopterygians. The homologies of the adductor
mandibulae complex are detailed in Lauder (1980),
and their mechanical advantage for jaw closing force
ranges across an order of magnitude from Lepisosteus
osseus (0.05) to Polypterus senegalus (0.42). This
means that L. osseus transmits only 5% of adductor
muscle force at the jaw tip, whereas P. senegalus
transmits up to 42% of muscle force to the jaw tip for
biting. Conversely, L. osseus multiplies jaw muscle
speed by a factor of 20, and P. senegalus by a factor
of just 2.4, illustrating the trade-off between force and
speed in jaw lever systems.

bite force chart.JPG
 
A heap of very odd books,piles of magazine articles and some very
knowing friends around the world and
lots of scientific papers my file size just for polys is some 256mb of
information that only took 6 years of research to compile-Anne
 
wow lol
 
Anne, you're awesome. I know I really appreciate the stockpile you've built up as I'm sure many of us do.
(woot 200th post!)
 
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