Live feeding and hognoses!

[Skiploder]

Ok look. I don't want to start a foolish forum war here but some of the assumptions you have made are faulty. First let me start with saying that in my post I stated that hognose snakes eat MAINLY frogs and toads. I did not say that they ate them exclusively. Most snakes are broad range opportunists, to clarify, not all snakes are but most. Some snakes do specialize.
And if you want to really get down to brass tax here when talking about the "Fangs" of hognose snakes that is really not the correct term. They are enlarged rear teeth. the term "Fangs" is reserved for a tooth like apparatus used for delivering a venom (in the cases of snakes). The enlarged rear teeth of the hognose do not deliver venom. They are neither a hallow delivery system, as in Viperidae and Elapidae, nor are they a grooved fang as in the venomous lizards. Also the enlarged rear teeth are not connected to a venom gland that produces, stores, and releases venom due to muscular contraction.

That is because the "venom" (another term thrown around when discussing hognose snakes) is not a venom. The substance being referred to is a toxin in the saliva. The system of toxin production and delivery in hognose snakes is very similar to, for example, the Northern Water snake. This snake produces a toxin with the same process as the hognose but the Northern Water Snakes toxin is a blood thinner. The toxin is in the saliva of the snake and when the teeth of the snake break the skin and cause bleeding the saliva in the mouth is able to flood over the wound and into the blood stream. The teeth neither direct nor deliver the toxin into the blood. This is the same process in hognose snakes.
As for the function of the enlarged rear teeth, you first have to distinguish the difference between the terms function and use when it comes to science. A function is the exact reason for the structure or behavior while a use is a possible reason that may be done with out the organism's knowledge. SO when taking those definitions the function of the enlarged rear teeth is to actually hold struggling prey. The uses of the teeth may be to pop frogs and toads, and open skin for the toxin to flow into the blood.
As for the evolution of the toxin and the enlarged rear teeth it is popular belief that both of these traits came from a common ancestor that the hognoses shared. This ancestor probably had a similar diet to the hognoses of today. And because of that diet evolved the beginnings of toxic saliva to counteract the toxins produced by its food and also enlarged rear teeth to help subdue its prey. This is backed up by the evidence that all of the existing hognoses have the characteristic up turned rostrum. This is believed to have been used for digging up the ancestors preferred diet of frogs and toads. Thus you can see the link between all species of existing hognoses, their enlarged rear fangs, and the formation of a toxin in the saliva. All changes in the content of the toxin is believed to be evolved after the split from the common ancestor. Again though this is the commonly accepted idea among scientists. Yes certain traits and attributes can be evolved in similar fashions among organisms that are unrelated for a long period of time. Convergent evolution is the term to describe this. An example of this is the marsupial mouse Antechinus sp. and common mice Peromyscus sp. Similar evolution and answers to similar problems but very different animals. But the species of hognose are very closely related and a common ancestor seems to be the more likely answer.

And just so people don't think I am just blowing smoke I would like to site just a couple of references I have obtained in acquiring my Bachelors degree in Wildlife Biology specialization in Herpetology for the University of Michigan.

1. Reptiles and Amphibians of the Great Lakes Region by James H. Harding. Professor of Science and private researcher of Herpetology at Michigan State University.

2. Reptile Care: An Atlas of Diseases and Treatments by Fredric L. Frye D.V.M, M.S, Fellow, Royal Society of Medicine.

3. Evidence of Mild Toxicity in Saliva of Hognose Snake (Heterodon) by Wayne H. McAlister. Published in the 19th volume of Herpetologica.

Thanks and once again I do not want to start a forum war but I think that it is important to give the most correct information possible to a person in need. I do realize that this is more then what the thread starter was asking for but I felt that it needed to be said. I think that you are a very educated person and that you obviously have a passion for reptiles and that is what the industry needs right now. I am very glad to call you a fellow herper.

No, no need to start a war. I will point out that your third source is often cited in reference to hognose toxicity, but has been more thoroughly clarified by many other researchers - correct me if I'm wrong but doesn't McAlister's work go back to the 60's? Fry, Wuster and others have done more recent, more thorough and more specified work and have further defined the components of hognose venom and the use of their rear teeth. The hobby has also punctured the myth that all hognose snakes are obligatory toad eaters.

Heterodon venom is comprised mainly of kallikrein toxins - which are also the main components in many other rear-fanged colubrids who do not regularly ingest toads.

People are in general agreement that hognose rear-teeth are not grooved. But this does not mean that this lack of a slightly less-evolved delivery system discounts the use of these teeth as fangs.

I think it would be instructive if we also point out which commonly accepted rear-fanged species also lack that groove. Well, hydrodynastes is one, as are rhabdophis. We are all aware that rhabdophis bites have proven fatal to humans and hydrodynastes are universally considered rear-fanged venomous.

As someone who has kept both dispholidus and thrasops, I can attest to the fact that the delivery system does not lessen the toxicity of the venom - only the efficacy in delivering it. While dispholidus evolved a fairly advanced venom delivery system (as far as rear-fanged snakes go), their cousins the thrasops did not. Once delivered into the prey, the effects of the venom are the same. I've seen too many mice die by thrasops bites to accept the argument that the lack of fang evolution diminishes the purpose of the venom.

Depending on locality, natural hognose diets run the gamut from mainly toads to mainly lizards. If all rear-fanged snakes (or to give a nod to your precise definition) all enlarged rear toothed snakes were mainly toad eaters, and if the front dentition of these snakes were considered inefficient in holding or capturing prey, I would gladly accept that the enlarged teeth had their evolutionary roots in holding prey.

However, the more recent findings center on the fact that rear fangs/teeth evolved and are embryonically formed separate of the rest of the snake's dentition. They are formed in the rear of the mouth because of that location's proximity to the venom gland. In other words, these fangs evolved separate of the rest of the teeth and in a location where they could conveniently form a gland/fang connection. For further clarification, refer to the papers published by Freek Vonk two or three years ago and research he and his colleagues performed.

As for us debating what is a fang, what is a tooth and whether the groove makes it a fang, or whether a Duvernoy's gland is really a gland, I would recommend that anyone interested read "Evolution of an Arsenal" by Fry, which further clarifies the various types of rear fang structures and the rebuttal to the often contrary minimilization of the duvernoy gland.

I already stated that the venom composition of heterodon is independent of prey. What has been accepted is that some species of heterodon have developed physiological adaptation that allow them to not be affected by toxins in the toad's skin.

I would love the opportunity to discuss this at length, but you are correct in that it is taking this post into unintended territory. I'm game for either starting out own thread where we can share sources and experience or, in order to make sure we don't cross wires here, PM me with your contact info and we can continue this via e-mail.

[Mikekrause2000]

Good answer Jorshaw, but because you did not cite using correct APA format guidelines, I can not accept it.

LOL

Hmm. im a little confused now, but i know what i need to feed my snake so i am happy. Thank you guys.

[mainbutter]

Good answer Jorshaw, but because you did not cite using correct APA format guidelines, I can not accept it.

best reply on the internet ever.