Duvernoy's Gland = Venomous?

[StudentoReptile]

Just curious where this discussion will go...

Does the presence of a Duvernoy's gland make the species in question venomous?

[dbank999]

This is a tough topic.

Some say that the gland is distinct from venom glands, and others say it is a primitive venom gland.

Also, just because the secretion from the gland can produce an adverse reaction, does not mean it is a venom, correct?

Perhaps the colubrids with this gland, "missed" the evolutionary train to evolve into venom glands such as those present in elapids and viperids, and thus only produces a small toxin? Others suggest that its purpose could be for digestion?

I don't really know much more about this... interesting post.

[CosmicOwl]

Wouldn't this depend on how you define venom?

[MDT]

Whether the DG is a venom gland homologue, or in fact an "under-developed" venom gland...it is a delivery system of sorts. I think I would lean towards a venom delivery system.

Interesting read:
Muscle and skin necrotizing and edema-forming activi... [Toxicon. 2004] - PubMed - NCBI

[MDT]

Originally Posted by CosmicOwl

Wouldn't this depend on how you define venom?

Nope...

venom is venom...

Def: poisonous fluid secreted by animals such as snakes and scorpions and typically injected into prey or aggressors by biting or stinging.

Just as discussed on the whole monitor/venom thing.....if your expectations of venom are how an elapid or box jelly fish venom works, you'll likely be underwhelmed with much of the venom in the animal kingdom. Just 'cause you don't drop dead with melted eyeballs in 15sec after a bite does not mean a critter ain't venomous....

[CosmicOwl]

Originally Posted by MDT

Nope...

venom is venom...

Def: poisonous fluid secreted by animals such as snakes and scorpions and typically injected into prey or aggressors by biting or stinging.

Just as discussed on the whole monitor/venom thing.....if your expectations of venom are how an elapid or box jelly fish venom works, you'll likely be underwhelmed with much of the venom in the animal kingdom. Just 'cause you don't drop dead with melted eyeballs in 15sec after a bite does not mean a critter ain't venomous....

That was what I was getting at. As far as I knew, any poisonous substance injected by one animal into another would be considered venom.

[StudentoReptile]

Our society just did a lecture on venom. Seems to be that it is not related to venom.

It is more akin to a saliva-producing gland, kinda like we see an ad for burgers and our mouth waters. The snake seizes prey, the Duvernoy's gland secretes saliva, and it so happens that the saliva may have paralyzing properties. It is not the same as the digesting and/or toxins seen in the venom of vipers or elapids.

SOOOOO....hognose snakes are NOT venomous!

[MDT]

Salivary lipase and ptyalin begin the digestive process in the mouth, so would human saliva be considered venom? Nope. Neurotoxic venom does not particularly aid in digestion in comparison to immobilizing prey. I'm in the camp that at the very least, DG are homologous to venom glands, if not primitive venom glands. I would be interested for Brian Fry to jump in this discussion as well (like he did in the varanid thread).....one thing I don't know and would be interesting to find out is what the histology of the DG is compared to an actual formed venom gland.

Did you read the abstract in the link I posted? DG gland secretions causing tissue necrosis...pretty interesting.

Btw...who did your talk at your meeting?