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Re: Venom in Sinornithosaurus



Jura wrote on this before I ended this, but here it goes...

> Assuming bipedal bodystyles can be shown in general to be associated w/ 
> cursorial lifestyles; and that predatory envenomation strategies, and the 
> presence of venom in vertebrates generally, is associated with slowness of 
> locomotion* -- It is not obvious what combination of lifestyle and 
> environment would be likely to elicit cursorial locomotion and a venom system 
> in a predator simultaneously. It also seems intuitively unlikely that a fit 
> cursorial predator would evolve an effective venom system, at least not w/out 
> some loss of locomotive fitness.

Well, although not cursorial, some shrews deliver venom and are not
particularly sluggish. There are also some fast spiders and water
beetles which are venomous also. I think venom may end up being useful
in many cases. For example, it would make it easier for a cursorial
wolf, even a lone one, to kill a bison, or to defend its kill from
bears. The cheetah would be much better with it... I do not know, it
may be always useful to defend yourself and to kill difficult prey
items. They may be somewhat energetically costly to afford (do not
really know), but there may be some cost-benefit relationship which
may make it more or less likely according to the particular case. For
example, if the prey is easy to kill mechanically and cannot injure
you easily, and there are no large enemies, venom may look
innecessary.

In addition, venomous predators have to move fast if preying on fast
prey, for example, snakes have to hit mice and lizards, very fast
little creatures, before they can react to the sight of the coming
predator.