Squirrels are most closely related to what? Rodents? Rabbits?

[Squirrelguy]

What other animals are squirrels most closely related to?

Rodents (rats / mice)? Rabbits? Guinnea pigs? Hamsters? Chipmunks? Chinchillas?

I'm asking in terms of GI physiology and food/diet and commercially available small-animal feed.

Many of these animals are coprophagic (they eat their own feces) which is also known as "hindgut fermenters". But I can find nothing in the internet in terms of authoritatively explaining if squirrels are also coprophagic.

Do wild squirrels routinely eat their own "first-pass" feces like rabbits and hamsters do?

[CritterMom]

No, though they frequently will drink their urine. They are closest to rats/mice - quite different from rabbits or guinea pigs.

[Cleo_13]

I did a project on squirrel phylogeny a few semesters ago for my evolution class. I still have the powerpoint, and this thread has caused me to go over it again. I find evolution fascinating, especially when it involves squirrels! I don't know about your specific question though except that rabbits are not rodents but all the other animals you mentioned are. Chipmunks are also in the squirrel family, so out of that list they are the most closely related:)

[Squirrelguy]

According to this University of Wisconsin research paper: http://www.uwosh.edu/projects/squirrel/docs/LabAnimal2006proof.pdf

They study the "13-lined ground squirrel" because it apparently hibernates. There are no such "13-lined" squirrels here in SW-Ontario (they look like chipmunks if you ask me - and chipmunks do live in holes in the ground).

Now I don't know if these "13-lined" squirrels are similar enough to the grey and black tree squirrels around here, but here's what they are feeding those captive 13-liners:

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DIET
According to most of the literature, commercial rat chow is the base diet for 13-liners. However, in our experience, 13-liners do not readily eat rat chow. Moreover, the natural 13-liner diet contains significant animal prey (e.g., ref. 32). Thus after our first year of keeping them we fed our 13-liners a base diet of commercial dog chow (IAMS Chunks) or cat chow (Purina Indoor Formula), con-
taining 26% or 30% protein, respectively. This compares with only 23% protein in commercial rat chow. Perhaps significantly, we noticed improved growth and ceased to observe both maternal cannibalism in the breeding colony and death during hibernation after we switched to higher protein chow. Sunflower seeds and greens (carrots and celery) supplemented the chow diet.
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That would be very useful if my backyard squirrels would actually eat a diet of mostly the "farm-grade" dry dog or cat food sold at TSC. I would reduce the amount of black-oil sunflower seeds I put out (cleaning the shells is going to be a pain this spring), but would still put out shelled peanuts once in a while.

[LeilaNami]

I did a project on squirrel phylogeny a few semesters ago for my evolution class. I still have the powerpoint, and this thread has caused me to go over it again. I find evolution fascinating, especially when it involves squirrels! I don't know about your specific question though except that rabbits are not rodents but all the other animals you mentioned are. Chipmunks are also in the squirrel family, so out of that list they are the most closely related:)

:goodpost

Squirrels are in the family Sciuridae and therefore will be most related to other animals in the same family. From the list, that would be chipmunks. All the others are in different families but still in the order Rodentia (all rodents) with the exception of rabbits which are in the order Lagomorpha (hares, rabbits, and pikas). This is a phylogenetic relationship and the methods of digestion is a shared derived character that would play a part in determining whether or not they should be in this family/order/etc.

Diet can be varied within the families depending on what niche they occupy. Flying squirrels and grey squirrels are in the same family but flying squirrels eat more insect protein than a grey squirrel would typically consume. That's not to say they won't consume it but in order to get a handle on diet, it would be imperative to know if they are ingesting something as an opportunistic behavior or if they are actively seeking it out as a part of their diet (such as flying squirrels). For example, an iguana is herbivorous and a captive diet should be entirely herbivorous, but wild iguanas will sometimes partake in eggs if given the opportunity.

If you are wanting a commercially, and readily available diet (meaning it is easy to find) that matches closely to the DV of what a squirrel food would, rat food would be the closest you could get since commercial chipmunk food (which I believe contains more protein and different nutritional content anyway) is a littler harder to come by.

[mdyoung216]

I know it's in the same family, but how close is a groundhog to a squirrel?

[island rehabber]

I know it's in the same family, but how close is a groundhog to a squirrel?

VERY close. They are both rodents, and from the family Sciuridae. Teeth grow similarly and diets are also similar except that groundhogs eat A LOT. Groundhogs, like chipmunks, are sciuridae who hibernate. Our tree squirrels don't.