Reptile & Amphibian Forums

I understand that this is a controversial topic, so I do apologize if it has been resolved adequately by the majority of regular participates of this forum, but I have to ask.

Has there been any definitive observations/studies that conclude that an exclusive diet of rodents adversely impacts (liver disease?) Eastern Hognose and most importantly (from my perspective) the South American Tri-colored Hognose. I have pair of SA Tri-colored Hognose that are glutens and growing very fast, I was wondering if their overall health is being jeopardized by me feeding them rodents on a regular basis? Should I reduce their feeding to once every two weeks? I have heard that multiply clutches have been produced from females on rodent diets which could be normal or an increased fecundity directly linked to the excess fat obtained from their rodent diets. The energy excreted from multiply clutches could decrease their longevity.

Thanks in advance for any responses, Ken

I don't know about Lystrophis, so this tidbit may be completely irrelevant in your situation, but I have spoken with someone who has seen problems with Eastern hognose maintained on a diet of haired rodents. He said that the livers in the animals were a bit fatty, but that they were not out of the ordinary for a captive animal fed such a diet (even natural rodent eaters). He did say that the intestines of the animals were lined with layers of hair (blocking effect). The situation probably caused other problems as well (e.g. nutrient absorption).
The story of said animals does seem similar to your own though (other than the death part, hopefully). They were fed appropriate sized rodents in their life span, grew very rapidly, and had large clutches. The downside was that the animals died prematurely. I can't remember the number of years, but I beleive it was somewhere around 5. The situation with the intestines was similar in all of the premature deaths.
That's as much info as I have on the matter, and I am trying to track down "the rest of the story." The person who told me about this wasn't the owner of the snakes, but was present for the necropsies. The other person who I am trying to find is now a DVM, possibly in Florida.
The owner kept many Eastern hogs, so I don't know if the premature deaths were a usual phenom, or just a problem that affected some of the animals. Hopefully I can get someone to make a post. Every time I get into this topic it makes me want to run out and start my own experiment.
Shane

I want to commend Shane for providing some decent information on the effects of all rodent diet on Eastern hognoses. Seriously. At this point, I have not been provided with, nor have I been able to dig up any credible information on the many claims I have heard about the detrimental effects of an all rodent diet. Currently there is such a vacuum for information on this subject, that I'm even willing to accept second or third hand anecdotal observations! 99.9 percent of the claims I have heard have all been from people who have had absolutely nothing to back it up with. This is the first date of information I have heard about the possible detrimental effects of an all rodent diet on Eastern hognoses.

Most of the speculation revolves around fatty liver disease, and the recent reason I heard was that hognoses need certain proteins found only in toads that are required for proper kidney function! Of course this person could not provide absolutely any sources for this information

Of course there is a lot of other information being left out here. The fundamental basis of supporters of an amphibian diet is very reasonable. Eastern hognoses in particular, eat a lot of amphibians in the wild, although it is not their only source of nutrition! However, with the lack of evidence to support the claims of many people who say that rodents killed their hognoses, and with many reasons for not using amphibians, I have been advocating the use of rodents for hognoses.

I can assure you that an all rodent diet is not the reason for an early demise in Eastern hognoses, as I personally have hognoses that have been fed no amphibians in the last 10 years. Personal communications with a few individuals have revealed that it is possible to feed an Eastern rodents out of the egg all the way through breeding.

PS- no speculation is given on the South American hognoses here, who are distantly, if it all, related.

Shane: Our last conversation several months ago, motivated me to do a thorough scientific literature research on hognoses. I have collected volumes of information, but as you can imagine that provides very little on the captive husbandry of Eastern hognoses. I wanted to encourage you to chase after your sources who did the necropsy on an Eastern hognose. It is only from people like me and you who work to settle these debates that any credible information will be revealed, and hopefully these debates will end.
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"It isn't pollution that's harming the environment. It's the impurities in our air and water that are doing it."
Governor George W. Bush, Jr.

"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)

You typed.... "However, with the lack of evidence to support the claims of many people who say that rodents killed their hognoses, and with many reasons for not using amphibians, I have been advocating the use of rodents for hognoses.

I can assure you that an all rodent diet is not the reason for an early demise in Eastern hognoses, as I personally have hognoses that have been fed no amphibians in the last 10 years"....

It's funny, but I think we've been at this for at least a year (probably two). In that time, your favorite figure is always 10 years. Anyone who cares to search the hognose archive can find that. I wasn't aware that time stands still.
Like I've implied before, if toads strike your emotion, you shouldn't keep platyrhinos. Shane

Thank you both for your detailed information obtained to date on the subject. I am no expert, but the individuals like you that have kept Easterns for a period of time are probably the best source of information.

It seems like only recently Easterns have only been commonly kept as pets/bred, therefore not too much historical captive husbandry info. is out there. I have lived in East Texas/Houston for a couple decades and as a herper, with all the orange/black/banded individuals I found, I never thought that Easterns could be switched over to feed readily on mice…tells you what I know (Ha). Interesting to note, I recently attended the ETHS Conference that during Lunch this subject came up, one reputable herper stated that a large Grey Band breeder was observing a higher number of eggs laid along with double clutching from WC females and once they were on a rodent diet, fecundity dropped off. He is now (as stated by another) purchases lizards (type do not know) from an individual in West Texas to feed exclusively his alterna females…….interesting at the least.

Ken, if you have any pics of the hogs you've found in the Houston and east TX area I'd love to see them. The color variation is awesome. Shane

Ah, it's a shame you are not interested in collaborating. And it's too bad you need to depend on technicalities to try and poke holes in my argument. Other than that, you accuse me of emotioned responses, when in fact I am basing my opinions on facts or the lack thereof.

For your information, we first had a discussion last Nov, not 2 yrs ago. I have been using the 10year figure for probably 2 yrs now. The reason is simple, we got her in June of 1993 from Glades, probably as an adult. In 2002, I simply rounded up, and now in 2004 I round down. I think it's ridiculous I have to explain this in the first place.

>if toads strike your emotion, you shouldn't keep platyrhinos.
I am guessing that the worldwide decline of amphibians doesn't "strike" you at all. If I used your line of reasoning, and lack of concern for other taxa, would you have problems with me feeding wild hogs that I find to other animals in our collection? We have a couple of kingsnakes, not to mention the birds of prey, red wolves, and bobcats. I don't think any of them would hessitate to suck a hognose down. In this case, I am simply including a natural part of the animal's diet, without any regard to the current population status of hogs, or their humane treatment! Sometimes I am amazed at the lack of concern by herpetoculturists for wild populations of the animals they are interested in, and ones that share similiar natural history.
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"It isn't pollution that's harming the environment. It's the impurities in our air and water that are doing it."
Governor George W. Bush, Jr.

"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)

I have to agree with Colchicine on this one. Most wild snakes aren't particular about what they eat....with the exception of my snake. I would be concerned about feeding a hognose live mice however. Due to the fact the mouse could inflict serious injury on the snake. Other than that, I think there is nothing wrong with feeding a snake a rodent diet and it's probably preferrable to needlessly killing our dwindling amphibian populations. Unless of course your snake refuses anything but frogs like mine. Of course I have no literature to back this up. Just an opinion based on common sense.

You wrote........"Most wild snakes aren't particular about what they eat....with the exception of my snake."........

Please substantiate why most wild snakes aren't particular about what they eat. Take a look at the prey section of a good field guide, and you may find a different level of "common sense." Shane

Because most reptiles with the exception of a few species, have a varied diet. I can substantiate these claims with the nitrogen fixation studies we are currently doing on reptiles in the Sevilleta National Wildlife Refuge. Now why don't you tell me what your research has revealed on reptile fixed diet studies.

You wrote........"Because most reptiles with the exception of a few species, have a varied diet.".......

Please give examples. When you say varied diet, are you talking about, lets say Pituophis, eating several different genera of rodents, or are you saying that they will happily eat anurans as well? Pituophis is just an example. Beside the fact that this thread is about platyrhinos, you should still substantiate your claim when it comes to "most" reptiles.

You wrote........"I can substantiate these claims with the nitrogen fixation studies we are currently doing on reptiles in the Sevilleta National Wildlife Refuge."........

I was under the impression that nitrogen fixation is a poor method for determining diet. Let's go back to the Pituophis example. Their diet is almost entirely warm blooded, especially as adults. Let's say it eats some shrews, and then a young rabbit. That would skew the nitrogen fixation results, no? In any case, you certainly aren't doing any nitrogen fixation results on platyrhinos.

You wrote........."Now why don't you tell me what your research has revealed on reptile fixed diet studies."........

While fixed diet is quite ambiguous, I'll go ahead and say that in the case of platyrhinos, it means they predominately feed on frogs and toads. In the case of other snakes, I'll say it means they show preference for a certain type of prey (e.g. warm blooded, or cold blooded, or insect, etc.). There are only a few American species that I can think of that are well known for crossing those boundaries (other than juvenile vs. adult diet).
Here you go, from: Werler, J. and Dixon, J. "Texas Snakes (Identification, Distribution, and Natural History)." 2000. Univ. of TX Press.
"A study of prey items consumed by this species in nature shows that it eats chiefly toads, as well as frogs and salamanders. Those amphibians together total more that 90 percent of the snake's diet in most places."
Here's another, from: Palmer, W. and Braswell, A. "Reptiles of North Carolina." 1995. Univ. of NC Press.
"The principal foods of this species are amphibians, especially toads of the genus Bufo. Many of the hognose snakes we caught regurgitated these anurans, and nearly all captives readily ate them."
How's that for common sense? Shane

I found myself reading through some threads and saw the Sev reference. Is this someone I know?
ian(in Albuquerque)

and I opt NOT to look in the latest field guide to reptiles as most have been written by hobbyists concerning their general observations and have very little scientific backing.

You wrote........"and I opt NOT to look in the latest field guide to reptiles as most have been written by hobbyists concerning their general observations and have very little scientific backing."........

You may well be correct that many state field guides are written by "hobbyists," but that in no way means they lack scientific backing. Anyone who chooses to use the scientific method can be considered a scientist. By the way, the sources I have cited were authored by professional scientists (if that is your basis of acceptance).
Shane

One of the most common problems with captive maintained animals is obesity. This can severly impact longevity, fertility and other aspects of life (and can cause fatty liver problems). Reptiles can be obese without many of the clinical signs that we attribute to them through the simple manner in which the fat is stored in the abdomen (spacing between the scales and neck size is an indication of a grossly obese animal).
Many people do not take into consideration the decrease in activity (and decrease in metabolic rate) related to captivity.
The rough metabolic needs of a snake can be estimated with some simple calculations (see Mader's chapter on Nutrition for a complete explanation) or by reference to an averaged chart. (I'm going to use the chart as a matter of convience). Standard metabolic rate (SMR) is the amount of energy required for normal resting body metabolism while increase metabolic needs in reptiles are typically calculated by multiplying by 1.1 to 2.5.
So off the table, a 100 gram generalized snake at 30 C (86 F) is 5.4 kcal/day. Times 7 days we get 37.8 kcals/week. An adult mouse (27 gram mouse ) provides 45.9 kcals more than an adequate weekly meal for a snake that isn't doing too much. Even a snake with increased metabolic needs will find this more than a sufficient meal (remember this is at an upper temperature).

Additionally has anyone considered that rodents may be more dense than a comparably sized toad or frog. Mid sized Wyoming toads at work typically weigh less than 20 grams but are an equivalent size to adult rodents (not burned out breeders) which are typically closer to 30 grams? In this case more mass (and thus more calories) of a food item is entering the animal with all else being equal.

In some snake eating snakes (king cobras to be specific) I have seen animals maintained on a rodent only diet for more than 12 years with no signs of ill health (other than those that can be attributed to being >26 years old) other than coughing up the occasional hair ball.

Some thoughts,

Ed

Ed, are you serious about the occasional hairball problem with King cobras? Shane

I've worked as a Keeper in the Dept. of Herpetology at the Philly Zoo since 1992. The only problem I have ever seen in a rodent diet in various snakes that could not be attributed to obesity was the occasional hairball in the king cobra. I even got the Eastern Coral snake to take unscented pinks after which it set a longevity record for being on exhibit (it has since passed on) (It was for close to 17 years if I rememeber correctly).

Ed

Thanks. These threads do get a bit convoluted at times; the only problem I've heard of re: platyrhinos is with haired rodents. You guys have it rough. When I visited the Singapore Zoo, the keepers were fortunate enough to have a ready supply of Reticulated python prey. Have you ever seen a King cough up scales Shane

Hi Shane,
No I haven't seen them cough up scales but when they go to the bathroom its one big runny mess when they are fed snakes.

Ed

You wrote........"For your information, we first had a discussion last Nov, not 2 yrs ago. I have been using the 10year figure for probably 2 yrs now. The reason is simple, we got her in June of 1993 from Glades, probably as an adult. In 2002, I simply rounded up, and now in 2004 I round down. I think it's ridiculous I have to explain this in the first place."..........

Perhaps the first time I replied to you was a year ago, but I've been reading and posting on this forum since at least June of '00. You may find that we've been at this for longer, as I originally posted as ShaneOfTX. It's funny that you boast your argument on fact, while you just admitted to fudging matters. It's also funny that you have mentioned having "hognoses" for 10 years, while it now appears you are only talking about one snake. In addition, you have absolutely no grounds for assuring anyone that feeding a diet of rodents is not harmful to platyrhinos. Even if you do have a snake that has gone 11 some years without eating amphibs, that isn't the longevity record. Premature death is still quite the possibility.

You wrote........"Ah, it's a shame you are not interested in collaborating. And it's too bad you need to depend on technicalities to try and poke holes in my argument. Other than that, you accuse me of emotioned responses, when in fact I am basing my opinions on facts or the lack thereof."........

Round and round on the facts. The last time I checked, one of the major purposes of a debate is to poke holes in another's defense. I have no interest in collaborating with you for two reasons:
1) You are emotionally biased when it come to feeding amphibs
2) You don't stick to the facts
I would lose credibility if I collaborated with someone like you.

You wrote........"I am guessing that the worldwide decline of amphibians doesn't "strike" you at all. If I used your line of reasoning, and lack of concern for other taxa,"........

You like to try and mislead other readers with something along the lines of "If I used your line of reasoning." That is completely asinine. Just to prove a point though, here's one that would follow your "worldwide decline of amphibs" reasoning.
Save the toads, kill a hognose.

You wrote........"would you have problems with me feeding wild hogs that I find to other animals in our collection? We have a couple of kingsnakes, not to mention the birds of prey, red wolves, and bobcats. I don't think any of them would hessitate to suck a hognose down. In this case, I am simply including a natural part of the animal's diet, without any regard to the current population status of hogs, or their humane treatment!"........

You see, now you're asking me to answer a question based on my emotion. It doesn't matter how I feel about your scenario. Will you ever understand that? Here's one for you, from : Palmer, W. and Braswell, A. "Reptiles of North Carolina. 1995. U of NC Press. (I highly recommend it)
"A large eastern kingsnake in New Hanover County was discovered swallowing a southern hognose snake, and it regurgitated two others shortly after it was caught (Robert Tregembo pers. comm.)."
Save a hognose, kill a kingsnake.

You wrote........"Sometimes I am amazed at the lack of concern by herpetoculturists for wild populations of the animals they are interested in, and ones that share similiar natural history."........

By the strictest definition I am a herpetoculturist, but I keep only 6 herps (amphibs and reptiles by the way). I am very big on natural history and field herping. It's funny that you threw in the herpetoculture bit. Most of the posters on this forum (that I've seen) who don't mind feeding their animals natural prey are quite interested in natural history and field herping. From what I've seen (with one exception, and even he's emotional when it comes to amphibs), only the emotional herpetoculturists give you support when it comes to this topic.
Shane

P.S. It's worth a note that I have heard that bobcats need hair in their diet; otherwise they will constantly suffer from runny stool. Do you feed your bobcat(s) commercial food. If it is the case that they need hair on a natural diet, wouldn't it seem ironic that my firsthand info on platyrhinos is the exact opposite problem.

snip "P.S. It's worth a note that I have heard that bobcats need hair in their diet; otherwise they will constantly suffer from runny stool. Do you feed your bobcat(s) commercial food. If it is the case that they need hair on a natural diet, wouldn't it seem ironic that my firsthand info on platyrhinos is the exact opposite problem"

Actually with bobcats it doesn't have to be hair, just some form of fiber to give the stool form. Commercial foods contain fiber to get this to work. At work we add beet pulp to the diet to accomplish the same thing.

Ed

Thanks for your input, Ed. I must say that I feel sorry for those bobcats. I'm pretty brave with food, but there are two items (so far) that will absolutely make me gag: liver and beets. I've yet to find even a southeast asian treat that will induce a similar response
Shane