Comments on: Venomous Komodo dragons kill prey with wound-and-poison tactics

By: Float like a butterfly, sting like a terror bird | Not Exactly Rocket Science | cYaNk

Thu, 19 Aug 2010 15:29:56 +0000

[...] charismatic predators, including the sabre-toothed cat, the great white shark, the Megalodon, the Komodo dragon, and the human. It was only a matter of time before terror birds took their [...]

By: MJohn

MJohn — Fri, 05 Mar 2010 17:46:01 +0000

@zutroi67
To be precise, all shock is defined by falling perfusion and, frequently, falling blood pressure…be that septic, hypovolemic, cardiogenic or obstructive shock. Blood pressure falls in septic shock just as it would in cardiogenic shock. And, shock due to blood loss is hypovolemic, not cardiogenic. Cardiogenic would be some defect of the function of the heart itself (like myocarditis).

By: Cyclura

Cyclura — Thu, 21 May 2009 17:58:16 +0000

There are no toxins listed in this article.

By: davem

davem — Thu, 21 May 2009 17:35:45 +0000

Why 600 toxins? That seems overkill. I’m struggling to see how a creature with 599 toxins in its bite might need to evolve the 600th…
Wouldn’t 10 or 20 be enough?

By: Fox1

Fox1 — Wed, 20 May 2009 15:01:05 +0000

Ah, varanids, how I love thee.
I did take an accidental bite from an exanthematicus once and didn’t notice any ill effects beyond the actual, physical trauma and the amount of bleeding seemed normal.
That was also the last time I fed a varanid by hand (hey, I was young….ish).

By: Zach Miller

Zach Miller — Tue, 19 May 2009 22:03:54 +0000

Right. Secondarily lost in many groups, and is BEING lost in some right now. Also, chameleons? Whoa!

By: Ed Yong

Ed Yong — Tue, 19 May 2009 21:09:14 +0000

So regarding the phylogeny, one of Fry's earlier papers suggested a clade called Toxicofera, which includes all snakes, and some lizards including monitors, iguanas, agamids, chameleons and the two species we've known were venomous for the longest time. I think the idea is that reptile venom evolved once in the origin of this group and has been subsequently lost in some.

By: Zach Miller

Zach Miller — Tue, 19 May 2009 21:01:51 +0000

Re-read bits of the post. You’re right! That’s terrifying. So in a way, it’s a simplified version of the gila monster system: the venom is almost mixing in with the saliva, which sops into the wound instantly.
So, damn. I guess there’s no way to tell for sure whether theropods had venom systems or not. It would certainly make life easier for the smaller carnivores, like compsognathids and microraptorines. But as we’ve seen with giant varanids, it’s clear that enormosity does not preclude the evolution of venom glands.
I suppose we’d have to use phylogenetic bracketing. No living crocs have venom, and as far as I know, no bird has a venom delivery system (in its mouth). So until we find some osteological evidence for venom in a dinosaur, the only thing we can say right now is “probably not.”

By: Ed Yong

Ed Yong — Tue, 19 May 2009 19:10:39 +0000

The only way you could really tell is if a theropod tooth (I assume it would be a theropod) had a groove or hollow channel in it, which would indicate the presence of venom

And as this story shows, the grooved tooth isn’t necessary for venom.

By: Zach Miller

Zach Miller — Tue, 19 May 2009 18:59:16 +0000

Heather, sadly, venom sacs don’t have osteological correlates. The only way you could really tell is if a theropod tooth (I assume it would be a theropod) had a groove or hollow channel in it, which would indicate the presence of venom. So far, that hasn’t been found.
Ed, wonderful article. Makes me all the more reluctant to visit the Komodo islands.