Captive Diets and Nutrition

[prgault]

Ok here goes. I'll preface this with the idea that most of you, with the exception of the rehabbers, probably have 1, 2 or 3 squirrels to feed. If so you may have more time to put in to the creation a perfect diet. This idea comes from mine and others experiences caring for a large, varied collection of wildlife over time.

The basic concept is that, behaviorally, animals have a way of knowing and choosing what they need and when. The problem arises when their choices are limited.

Along with a species specific, formulated, pelleted diet, the best thing we can do nutritionally is to provide our animals with the widest variety of choices possible based upon knowledge of the wild diet. If this is done in conjunction with proper environmental conditions, animals seem to have a combination of behaviors and physiology that enable them to maintain a proper nutritional balance (homeostasis). No otherwise healthy food (non-toxic) should be excluded from a diet based on a single component e.g. phosphorus content.

Interestingly, at least to me, this holds true for the living environment as well, and the relatively new concept of behavioral or environmental enrichment is somewhat based upon providing animals with choices, again based on the current best knowledge of the specific requirements, in their enclosure.

Here at our facility we are currently researching changes in our orphan protocols that will reflect the natural environment. This include raising orphaned squirrels in wooden nest boxes from day 1, to emulate the microhabitat of a tree cavity, and placing the nestbox in an outdoor enclosure upon or just prior to weaning. In these enclosures we will provide as much natural food as we can collect. we are also looking in to altering our diets seasonally.

[4skwerlz]

No debate here....everything you've said sounds reasonable to me. My work here has been with permanently captive or "pet" squirrels, who have different nutritional needs than to-be-released animals, or even those that are captive in large naturalized environments, such as in zoos. In fact, pet squirrels have some special problems. Their activity level is so much lower than that of wilds that it would be impossible for them to eat enough wild foods to fulfill their nutrient needs. Thus, the need for a concentrated food. However, I can't say how strongly I agree with providing a variety of fresh foods, including wild foods, in addition to rodent block for any captive animal. For variety, amusement, chewing opportunities, additional nutrition, and IMO a bit of a nutritional safety net. Since we can't be sure the rodent block is nutritionally perfect--in fact it probably isn't--a selection of natural foods allows the squirrel to fill any nutritional gaps by using their instinct to forage for the foods they need. For to-be-released squirrels, there is another benefit of course: the squirrel learns to eat the natural foods that will be his sole diet once released. Along those lines, do you provide insects, eggs, or fungi to your animals?

Another problem with long-term captives is that even small nutritional gaps can create health issues over the 10+ years that a pet squirrel is expected to live. Issues like glycemic load suddenly become important as well; and we have seen some diabetes in pet squirrels.

Another issue was the idea of feeding commercial rodent block for the squirrel's entire lifespan. Most are corn- or soy-based, and these would not be a large part of their natural diet, as well as being high in glycemic load. The squirrel's natural diet (mast, buds, flowers, wild plants, insects, eggs....etc.), are all very low in GL, suggesting they might have little tolerance over the long term for a high-carbohydrate diet. These are some of the reasons the squirrel blocks were developed as an alternative to commercial rodent blocks. (There was also the issue of palatability. We've found that most squirrels that are not introduced to rodent blocks shortly after weaning, simply won't eat them.)

Right now we recommend a diet consisting of rodent block or squirrel blocks, a variety of healthy vegetables, natural foods from outside, up to 2 nuts per day, and limited treats like fruit.

Feeding foods ad libitum has not worked out well for pet squirrels, except for vegetables and wild foods. Some combination of the squirrel's instinct to select the most energy-dense food available (usually nuts), their natural caching behavior, and possibly a loss of part of their natural instinct to choose the foods they need nutritionally, typically results in an unbalanced diet. A captive squirrel's intake is so limited (due to their low activity level) that there's little margin for error, and I tend to recommend that people not allow pet squirrels to maintain food caches, and to keep careful track of what they eat.

These are some of the issues we've been dealing with over the past couple of years in trying to improve the diet of pet squirrels. I'm delighted to have a real expert onboard, especially a wildlife biologist like yourself. I hope to learn a lot from you.

[island rehabber]

Excellent thread, both of you :bowdown:bowdown
I don't have much to contribute at this time, as I only raise to release, but I am looking forward to real ground-breaking research here. We have TSB's unique population of pet squirrels, non-releasable wild squirrels, and releasable wild squirrels to learn from. My dream is to establish best practices for squirrel care and make MBD nothing but a dim, horrible memory......too ambitious, you think? :D

[PBluejay2]

The basic concept is that, behaviorally, animals have a way of knowing and choosing what they need and when. The problem arises when their choices are limited.

I think is addressed this, but squirrels are notorious for eating the "goodies" and ignoring foods that may be better for them. Just put one rodent block (even a 4swerlz block) and one half of a pecan in a squirrel's cage each day for x number of days count how many pecans are left and how many blocks remain untouched at the bottom of the cage--and this is for any squirrel, no matter how deficient in nutrients it may be.

Along with a species specific, formulated, pelleted diet, the best thing we can do nutritionally is to provide our animals with the widest variety of choices possible based upon knowledge of the wild diet. If this is done in conjunction with proper environmental conditions, animals seem to have a combination of behaviors and physiology that enable them to maintain a proper nutritional balance (homeostasis). No otherwise healthy food (non-toxic) should be excluded from a diet based on a single component e.g. phosphorus content.

It's very difficult to imitate the wild diet of a squirrel, even if we knew what all went in to that diet, on a consistent basis, and I'm surprised 4s didn't jump on this one. If any squirrel has to be kept for any length of time (more than a couple of weeks) even one destined to be released, I would think, and I thought most had already agreed, it should be kept on a high calcium/low phosphorus diet, eliminating foods that are so out of balance (corn, sunflower seeds, etc.) they could contribute to nutritional problems very quickly.

Here at our facility we are currently researching changes in our orphan protocols that will reflect the natural environment. This include raising orphaned squirrels in wooden nest boxes from day 1, to emulate the microhabitat of a tree cavity, and placing the nestbox in an outdoor enclosure upon or just prior to weaning. In these enclosures we will provide as much natural food as we can collect. we are also looking in to altering our diets seasonally.

I'm not sure how wise, practical, even safe "raising orphaned squirrels in wooden nest boxes from day 1" is. If "day 1" means pinkies up to six-weeks or so, how do you propose providing supplemental heat? Also, it would seem to be more difficult to monitor babies tucked away in a wooden box. And are these boxes to be well-seasoned so that the fumes and oils from the wood do not pose risks? I suppose this new protocol seems like you're going to make things hard on yourself for no good reason. Until their eyes are open, all these babies know is that they're in a nice, warm, comfortable, safe place--be it a wooden nest box or a tupperware container.

I also hope you're very careful about the natural foods you collect. I'm not sure exactly how much training an adolescent receives from its mother regarding food selection, but on the basis of personal observation I believe some is involved. And while squirrels probably instinctively know what to eat and what not for the most part, I'd be concerned about young ones "experimenting" or sampling toxic ones. As far as collecting these foods themselves, I hope you have some tree-climbing gear!

[4skwerlz]

Along with a species specific, formulated, pelleted diet, the best thing we can do nutritionally is to provide our animals with the widest variety of choices possible based upon knowledge of the wild diet. If this is done in conjunction with proper environmental conditions, animals seem to have a combination of behaviors and physiology that enable them to maintain a proper nutritional balance (homeostasis). No otherwise healthy food (non-toxic) should be excluded from a diet based on a single component e.g. phosphorus content.


It's very difficult to imitate the wild diet of a squirrel, even if we knew what all went in to that diet, on a consistent basis, and I'm surprised 4s didn't jump on this one. If any squirrel has to be kept for any length of time (more than a couple of weeks) even one destined to be released, I would think, and I thought most had already agreed, it should be kept on a high calcium/low phosphorus diet, eliminating foods that are so out of balance (corn, sunflower seeds, etc.) they could contribute to nutritional problems very quickly.

I thought I did address this. I don't think Prgault is suggesting the diet should be 100% natural foods. They feed rodent block + natural foods, which is probably ideal for the to-be-released squirrels such as Prgault is caretaking. I did point out that a 100% wild-food diet wouldn't work for captives even if it were practical, since they can't eat enough to meet their nutrient needs.

And re: the calcium/phosphorus issue, I simply don't see the need to worry about it as long as you are following the protocol of 70% rodent block, 20% healthy veggies, 10% wild foods, and limited treats. Especially if you're following the "Healthy Diet" lists, from which the really high phosphorus foods, like pine nuts, have either been excluded or listed as "treats" to be fed very sparingly. The squirrel blocks were specifically designed to mesh with this protocol, e.g., the Ca/phos ratio is adjusted to make room for a few high-phos treats like nuts. If you're not using this protocol, e.g., trying to feed a kitchen-based diet with little or no rodent block, and not limiting nuts/seeds, then of course you'd have to watch that Ca/phos ratio like a hawk.

[prgault]

First, I am no expert, I only play one at work and on the internet.:D

I should point out that we do try to limit quantities, ad-libitum diets don't seem to work with many species of captive animals. We do offer eggshells, cuttle bones, lichens, pine cones, deer antlers, oak branches and mushrooms, and I hope incorporate more insects this year. I should also point out that this diet appears to be have been successful, at least with the few long term or permanent squirrels I have worked with.

Another interesting concept arises from this discussion, I was taught a long time ago, and have come to believe that we don't need to "take care" of our captive wildlife, we need only to provide them with the ability to care for themselves, much like the would in the wild. It may all come down to the differing needs among zoo (and similar captives), rehab, and pet squirrels.

It also may come down to whether or not you accept the assumption that all things being equal, animals will usually make the right choice about food.

P_

PS what does this :sanp3 mean?

[prgault]

Hmm Pecans vs rodent chow, you don't really want me to start experimenting with squirrels do you?:D

The idea is not so much to duplicate a wild diets or environments as it is to base our protocols on good scientific knowledge of the wild diet.

Concerning nest boxes, I haven't worked out all of the details yet, but they will be heated, and provided with natural squirrel nesting materials like strips of bark. The they will be constructed of whatever material is used to make the millions of bluebird, wood duck and other cavity nester boxes that have been used successfully for years. As to monitoring, for me feeding times are when you should "monitor" infants. The rest of the time you should leave them alone, while of course monitoring their environment.

Again, the purpose of all of this is to emulate the environment of a natural cavity. I think assuming the infants do not know the difference, or at least are not affected by the difference could be a mistake.

Before I get to far away from nutrition, (sorry) Let me address possible toxicity issues in collected food items. The Association of Zoological Horticulturists and The American American Association of Zookeepers both publish lists of "acceptable" and potentially toxic plants. I pretty much never offer anything without checking these.

Thanks for letiing me play.

P_

[4skwerlz]

I think assuming the infants do not know the difference, or at least are not affected by the difference could be a mistake.

Before I get to far away from nutrition, (sorry) Let me address possible toxicity issues in collected food items. The Association of Zoological Horticulturists and The American American Association of Zookeepers both publish lists of "acceptable" and potentially toxic plants. I pretty much never offer anything without checking these.

Thanks for letiing me play.

P_

It is possible they "imprint" on outdoor sounds while still very young. If that's the case, it could be an advantage for the babies to remain outside. It will be interesting to see how your babies do with this system.

I'd like to see that list of toxic plants. Although it appears that squirrels are able to eat many plants that are toxic to other animals. The only instance I can think of where a squirrel died from eating a toxic plant was one that died after chewing on a yew branch. Still, we're very careful about what we bring inside for our pet squirrels.

[bobbygoldberg]

Cool, I'd like to learn more about Weight loss (http://www.10facts.com/catsub/Health/Weight-Loss.html)

[PBluejay2]

Ummm--
Hmm Pecans vs rodent chow, you don't really want me to start experimenting with squirrels do you?:D

The idea is not so much to duplicate a wild diets or environments as it is to base our protocols on good scientific knowledge of the wild diet.

Concerning nest boxes, I haven't worked out all of the details yet, but they will be heated, and provided with natural squirrel nesting materials like strips of bark. The they will be constructed of whatever material is used to make the millions of bluebird, wood duck and other cavity nester boxes that have been used successfully for years. As to monitoring, for me feeding times are when you should "monitor" infants. The rest of the time you should leave them alone, while of course monitoring their environment.

Again, the purpose of all of this is to emulate the environment of a natural cavity. I think assuming the infants do not know the difference, or at least are not affected by the difference could be a mistake.

Before I get to far away from nutrition, (sorry) Let me address possible toxicity issues in collected food items. The Association of Zoological Horticulturists and The American American Association of Zookeepers both publish lists of "acceptable" and potentially toxic plants. I pretty much never offer anything without checking these.

Thanks for letiing me play.

P_

[PBluejay2]

Ummm--
Hmm Pecans vs rodent chow, you don't really want me to start experimenting with squirrels do you?:D

Absolutely not!

Concerning nest boxes, I haven't worked out all of the details yet, but they will be heated, and provided with natural squirrel nesting materials like strips of bark. The they will be constructed of whatever material is used to make the millions of bluebird, wood duck and other cavity nester boxes that have been used successfully for years. As to monitoring, for me feeding times are when you should "monitor" infants. The rest of the time you should leave them alone, while of course monitoring their environment.

Again, the purpose of all of this is to emulate the environment of a natural cavity. I think assuming the infants do not know the difference, or at least are not affected by the difference could be a mistake.

Since you work at a facility, I assume you deal with more than just squirrels. I don't mean to sound facetious, but are we to assume this new protocol will be applied to all animals and you're going to weave together twig nests for most baby birds, construct similar but larger nest boxes for all raccoons, make heated pouches for all opposums, construct partially submerged lodges for all beavers, create earthen burrows for all armadillos, tortoises, and skunks, manufacture caves for all bats--in short, try to emulate the natural nesting environment for all species? If so, you must have one helluva facility!P_

[PBluejay2]

The only instance I can think of where a squirrel died from eating a toxic plant was one that died after chewing on a yew branch. Still, we're very careful about what we bring inside for our pet squirrels.

I know of one that died from sampling a sago palm nut.

[prgault]

Since you work at a facility, I assume you deal with more than just squirrels. I don't mean to sound facetious, but are we to assume this new protocol will be applied to all animals and you're going to weave together twig nests for most baby birds, construct similar but larger nest boxes for all raccoons, make heated pouches for all opposums, construct partially submerged lodges for all beavers, create earthen burrows for all armadillos, tortoises, and skunks, manufacture caves for all bats--in short, try to emulate the natural nesting environment for all species? If so, you must have one helluva facility!P_

I think we do, and we are continually trying to grow and learn.

Actually it shouldn't be that hard, most of these can be easily constructed. Pouches are already made and reccomended for opossums. Litter dens for raccoons and older juvy opossums, can basically be piles of leaves inside a container. Burrows for younger fossorial species are made with boxes of sand. I have even seen young tortoises dig their own in a sweater box.

Don't take this as a shot, but I am curious as to why someone with your apparent passion for squirrels and other wildlife would think these types of efforts are too much trouble?

The beaver thing might be a tough one. :thinking

Should we start another thread somewhere else?

[island rehabber]

Should we start another thread somewhere else?

I don't think you all need to start another thread, but I've been asked to monitor this thread because it's going in a somewhat contentious direction. PBluejay2, I know you are an educator and no one appreciates continuing ed more than I do, but let's keep it warm and fuzzy if possible? :D

This is one of the more scientifically sophisticated threads on TSB and I'd hate to see it dissolve into nit-picking or whatever. Now please, carry on with this extremely important and interesting topic, and I won't interrupt again. Peace. :peace

[PBluejay2]

I apologize if I came across as not being warm and fuzzy! I certainly didn't mean to! I was just trying to make a point about how cumbersome an attempt to recreate nesting environments may be and how for infants I question its necessity. PG has a facility, and I assume enough manpower and space to manufacture and accomodate such a set-up (depending on the number of animals, I suppose). I can fully understand and agree with providing nest boxes for juveniles (say when they're old enough to be put in a cage and climb in and out of the things by themselves), but again, for pinkies and infants? I'd have a hard time bringing myself to put a pinkie down in wooden box on a pile of leaves, and while PG is right about limiting contact except at feeding (every two hours or so), I'd be afraid I couldn't hear any distress "peep" through the more sound insulating wood. Rehabbers over the years have raised and released successfully thousands upon thousands of squirrels, most of whom I assume without going to such lengths. Don't get me wrong: I do and will do everything I can for the babies I raise, but if this year was like last year, I'm afraid half of the walls in my house would be lined with nest boxes if I followed this protocol.

[PBluejay2]

A quickie, and I'll try to shut up. I read over the thread, IR, and don't see where I was "contentious," but again if I appeared so I apologize. Debate/discussion inherently means there is more than one point of view. I do see where the thread has veered away from its initial topic, however, and hopefully someone will chime in and get it back on track, but forgive my one last question to PG about the nest boxes: PG, are all your infant animals kept at your facility with someone there to feed 24/7? Another difficulty I would have following this protocol is the fact that I've had at times to take over a dozen babies with me to work to feed between classes. I can't imagine how I could keep them in nest boxes and carry them back and forth. Finally, at one time I had thirty nursing babies last year, and feeding and stimulating them had to be assembly-line fashion to get finished in time for the next feeding. Having their "containers" lined up on a table so i didn't have to get up and down (and thankfully not have to open up nest boxes and dig around for them) was a great help. Anyway, so what about that captive diet again?

[4skwerlz]

Prgault, do you do necropsies on any of your captive squirrels that die?

[PBluejay2]

Prgault, do you do necropsies on any of your captive squirrels that die?

Good question! (If, and I hope, the next one is "Do you examine stomach contents?" (keeping in line with the topic)), but I understand it takes quite a lab to figure out what each speck of stomach mush may be.

[prgault]

We haven't in the past, usually because we know the cause of death. Oddly enough we don't really see that many injured adult squirrels. I would like us to do more research of that type. I've done stomach contents on birds and other small mammals, just not squirrels. Depending on the species you and its diet can id stomach content down to family, sometimes further with a pretty basic setup. The hard part is developing the key.

If we have something in the freezer when I get back to work I'll give it a shot.

P-

[4skwerlz]

Do you do basic bloodwork on your healthy squirrels? There's still a lack of consensus on norms for levels of plasma glucose, triglycerides, thyroid hormone, Ca, P, Vit D, etc. Any possibility of bone density tests?

In terms of necropsy, I'd be very interested in any liver/kidney pathology. Especially any findings of fatty liver, enlarged liver or kidneys, or nephrocalcinosis. Also calcification of other soft tissues, iron levels in the liver, and iron accumulations in other tissues.

Was also wondering about your incidence of malocclusions.

[prgault]

If we have non-releasable animal that we are keeping as an ambassador, blood work would be a part of its yearly exam. Other wise that type of blood work is only done at the recomendation of the our vet.

We can do some basic testing in house like hydration and I think RBC. I would have to ask about bone density testing but I would think those would be useful for suspected MBD.

We have seen at least 1 older adult with a very reduced kidney. As far as I know we have not done any tissue pathology in my 4 years. We have a few seasonal mystery illnesses we see, mostly in birds, where I see a real need for this type of testing but we are poor.

Two cases of maloclusion that I am aware of, both most likely related to poor nutrition (MBD) and a soft diet.

Hmmm :thinking , I wonder if my blood glucose meter would work on a squirrel...

[4skwerlz]

Hmmm :thinking , I wonder if my blood glucose meter would work on a squirrel...

I wonder if you'd have any fingers left if you tried it....:D

Actually, I understand this is painless when done on end of the tail.