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My '06 EDB took its first rat day before yesterday. It ate a medium frozen-thawed rat in lieu of its usual 2 jumbo mice. I had posted below regarding concerns I had of this snake preferring mice only into adulthood. Looks like my feeding worries with this one are mostly over.

Regards,
WK

That's a very handsome EDB! We had a similar concern with our 4 year old EDB who until about a year ago would only take frozen/thawed rodents if it was warmed up in a microwave for about 8 seconds prior to being fed; drove us crazy (that's a practice I typically do not condone as you can create dangerously hot internal core temps in the prey animals - we actually check the inner core with a thermometer before feeding when I have to do this). Now, he takes frozen/thawed at room temp like there's no tomorrow. They are a finicky bunch at times but I can't think of a more stunning rattler than the adamanteus.

Rob Carmichael, Curator
The Wildlife Discovery Center

>>My '06 EDB took its first rat day before yesterday. It ate a medium frozen-thawed rat in lieu of its usual 2 jumbo mice. I had posted below regarding concerns I had of this snake preferring mice only into adulthood. Looks like my feeding worries with this one are mostly over.
>>
>>Regards,
>>WK
>>
>>
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Rob Carmichael, Curator
The Wildlife Discovery Center at Elawa Farm
Lake Forest, IL

Rob,

Wouldn't hot water work? Even with picky bushmasters, which typically want rodents much warmer than other vipers, very hot tap water works.

The only EDB I ever kept (for a short time) was a WC and was the exact opposite. I had to thaw the rat, then lay it in the cage and wait. Usually the snake wouldn't eat the rat until it had been in there a couple of days and started to smell funky.

MH

I found that I had to soak the prey in hot water for quite some time before the inner core was warm to elicit a strike from heat picked from the loreal pits. I also experienced problems with skin rupturing, or, rupturing when the snake struck the prey. Nuking the prey in a microwave for 5-10 seconds kept the outside of the prey fresh while warming the inner core which seemed to be the important key with this snake. I've done the same with bushmasters and it worked very well. Of course, placing these same rodents on the dash of my car in the hot sun works very well too.

>>Rob,
>>
>>Wouldn't hot water work? Even with picky bushmasters, which typically want rodents much warmer than other vipers, very hot tap water works.
>>
>>The only EDB I ever kept (for a short time) was a WC and was the exact opposite. I had to thaw the rat, then lay it in the cage and wait. Usually the snake wouldn't eat the rat until it had been in there a couple of days and started to smell funky.
>>
>>MH
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Rob Carmichael, Curator
The Wildlife Discovery Center at Elawa Farm
Lake Forest, IL

One would think that the loreal pits on the snake just pick up the surface temperature whether or not the inside is warm. Infrared radiation is what is detected by the pits and it is at a long enough of a wavelength that it wouldn't readily pass through layers of connective tissues, flesh, etc and that the heat signature from the inside of the animal would not be directly seen by the snake. Rather the snake would see the heating of the skin from the heat being conducted from the warm insides. I'm not doubting your technique. It just seems that some animals are quirky and like to be fed differently.

Although I haven't seen any recent studies done, my hunch is that there's more to the loreal pits than meets the eye. There's no doubt that they are far more sensitive to temp changes than we imagined and that probably includes recognizing core temps through various layers of skin, etc. We oftentimes make assumptions about physiological processes (such as heat pits) because it makes sense to us. In reality, particularly in the natural world, what makes sense to us and what really happens are usually worlds apart. But, you are right, some snakes are just quirky in their captive habits and that may very well be a good enough explanation. If anyone has seen any recent studies done on this subject I'd love to hear about it.

>>One would think that the loreal pits on the snake just pick up the surface temperature whether or not the inside is warm. Infrared radiation is what is detected by the pits and it is at a long enough of a wavelength that it wouldn't readily pass through layers of connective tissues, flesh, etc and that the heat signature from the inside of the animal would not be directly seen by the snake. Rather the snake would see the heating of the skin from the heat being conducted from the warm insides. I'm not doubting your technique. It just seems that some animals are quirky and like to be fed differently.
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Rob Carmichael, Curator
The Wildlife Discovery Center at Elawa Farm
Lake Forest, IL

This seems to be the case. There is evidence showing heat pits are sensitive to energy with wavelengths beyond the infrared (heat) range. I linked a paper below showing the sensitivity spans wavelengths from UV to infrared (which includes visible spectra). What is particularly interesting is that the pit organ wavelength sensitivity maximums correspond well with maximal absorption spectra of water and blood. Since the pit membrane is highly vascularized, the authors speculate that temperature changes in the pit organ tissue caused by absorption of electromagnetic energy (spanning UV to infrared!) is how the environment is interpreted.

Bottom line is that the pit is sensitive to a broad wavelength range and is seeing much more than simple environmental heat. It may have the capability of transforming wavelengths from other spectra into heat signals in the the pit membrane which the snake may be using to sense the environment. This is interesting because it opens up the possibility that these snakes can possibly do things like "feel" colors.

>>>Although I haven't seen any recent studies done, my hunch is that there's more to the loreal pits than meets the eye. There's no doubt that they are far more sensitive to temp changes than we imagined…

Wide-band spectral tuning of heat receptors

Nice article.

I was unaware that heat sensing pits in snakes were so sensitive to such a spectrum of wavelength... However, how it applies here needs to be kept in mind in the interpretation of their results.

The pits are receptors... They detect things. Their prey items are not emmitting x-rays, gamma rays, ultraviolet, whatever radation that you want to talk about. The prety is mainly emmitting infra red radiation. The other wavelengths discussed are not being emmitted by the prey item, so whether or not these wavelengths can be detected is moot. As mentioned earlier, infrared doesn't have the penetrating power to be seen through appreciable solids such as skin, fat, connective tissue etc.

My comments were in response to the segment of Rob's post I included in my reply, not to the microwave question so you shouldn't view the findings of the linked study in the context of microwaving rodents. In a natural setting, or even one involving feeding captive animals live prey, the proposed broad-spectrum sensing capability of loreal pits is interesting. Of course, prey animals do not endogenously produce visible light, but external light is reflected from their surface in a way that distinguishes their body profile from the surrounding environment. The data in the linked study suggest snakes with loreal pits may be able to detect this difference. Also, it is known that rodent urine reflects light in the ultraviolet range so the fact that UV frequencies seem to be detectable by loreal pits is also quite interesting because this may provide a way for these snakes to identify trails frequently used by traveling rodents.

But going back to the microwaved mouse, I don't think that the internal core is the only portion that warms when the animal is nuked. As I said in my reply to Matt below, microwaves preferentially heat water-containing areas. Therefore, I think a microwaved rodent would present a heterogeneous heat signature to loreal pits. This type of signature may in fact be closer to the natural heat signature of a rodent as compared to the uniform surface heating you would obtain with immersion in hot water or sunlight. Have a look at the microwaved burritos photo below to see what I mean by heterogeneous heat signature.

Of course, this is only of academic interest to someone responsible for the well being of a captive snake. If the snake prefers microwaved mice and is able to eat them safely, I say feed it microwaved mice.

WK

Yes, but the physical limitations of the radiation that is emmitted (and therefore detected by the snake) is low enough of energy that it cannot be detected through solids. The surface (or very near the surface) only is what will be detected. The prey items are emmitting infrared, and it is a physical limitation of light, not he physiological process of detection that limits the perception of inside vs. outside temps.

I'm curious how it heats the middle but not the outside? Everytime I microwave a frozen dinner, the outside gets scalding hot, while the inside sometimes is still frozen, hence I have to reheat it again. Do rodents not warm up the same way? I've never bothered microwaving them, for fear that they would explode inside my microwave (I'm not buying another one for rodents only).

My understanding of easterns (though I've only kept the one personally, but we had another one at Reptiland) was that they were simply finicky about the smell of the prey, especially if they were WC and used to wild prey (rabbits, squirrels, mice voles, etc.)

Microwaves heat by causing molecules to rub against each other. Water molecules are the main ones involved so parts of the nuked item that are high in water content will heat up more than those that are drier. That's why you can lick the outside of a microwaved Dolly Madison fruit pie while the inside will fry your tongue. If the entire food item has similar water content than the outside will heat more than the inside because microwaves will be absorbed by outer layers and less will reach the inside.

Regards,
WK

>>>>I'm curious how it heats the middle but not the outside? Everytime I microwave a frozen dinner, the outside gets scalding hot, while the inside sometimes is still frozen, hence I have to reheat it again. Do rodents not warm up the same way? I've never bothered microwaving them, for fear that they would explode inside my microwave (I'm not buying another one for rodents only).

Thanks Rob. EDBs are my favorite rattlesnakes with horridus coming in a close second. This EDB has eaten live hopper mice only twice in its life. It's eaten frozen-thawed exclusively since I've had it. I heat the frozen rodents too but do so by putting them in a Zip-Lock and placing the bag in sunlight. It takes a while but they soon get toasty. If they get too hot, though, their guts explode. I let them cool until they feel slightly warm to the touch then feed.

Until recently, if a thawed mouse had even a hint of rat scent on it, this EDB would rattle and run from it like it was Godzilla. I put a dark hide box in the cage and eased the head of a thawed rat into the entrance which triggered a strong bite from the snake. I left the rat at the entrance and it was gone a few minutes later. I used to keep this species in the early 1990s and never had one refuse fresh killed rodents of any kind so this one's behavior had me a little puzzled. Like you said, they're a finicky bunch!

Regards,
Wasil

n/t
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Venomous snakes---best hobby on earth!
Bill Huseth

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