Why do Squirrels Love Aluminum?

[Sanborn Chase]

Does anyone know why squirrels gnaw on aluminum?

 

[berkeman]

Does anyone know why squirrels gnaw on aluminum?

What have you found in your reading? And anecdotally, I've never seen them do this. What state/country are you in?

 

[Sanborn Chase]

If you'll type in"squirrels eating aluminum" in Google you'll see many people are experiencing this, but there are no explanations. They're eating siding, lawn furniture, fence ties, gutters, even power lines. They've cut my power many times; we had to go with copper. Some say they eat that and lead, too, but I've not seen that. I'm in the southeast U.S.

 

[phinds]

Does anyone know why squirrels gnaw on aluminum?

Because it is a soft metal and helps them control the size of their teeth without chipping them.

More appropriately, I should say that it is because it is one of many materials that are neither too hard nor too soft for them to use to control the growth of their teeth.

 

[Sanborn Chase]

Yes, that seems to be the obvious answer, but another body of evidence points to their need for aluminum oxide or other metal oxides, perhaps in an effort to control a botfly infestation. The linemen swear they don't go for the new aluminum. My experience is limited to the eastern grays (Sciurus carolinensis).
Mr. Phinds!: it's so nice to hear from you again. My, you do soar above us like an intellectual eagle. Perhaps we should see about little squirrel implants...dental.

 

[jim mcnamara]

As an aside: Aluminum salts (some of them) like AlCl₃, are extremely toxic. Aluminum is not a required nutrient for mammals AFAIK.
High aluminum levels in water causes neural plaques to form in mammalian brain tissue. Humans can have this happen as well.

[partial answer]
Squirrel incisors have a very hard dentine layer toward the front, and softer dentine in back. As they gnaw something like wood and apparently aluminum metal, it sharpens the incisor, by differential wear. Those teeth grow constantly, and without gnawing activity their jaws would eventually be held wide open. This is why guinea pigs, rabbits, and other related animals that have incisors and diets like squirrels require chew sticks in their cages. Squirrel teeth are extra hard to accommodate a diet that usually includes hard shelled nuts.
[/partial answer]

Why they have become aluminum connoisseurs is interesting to say the least. Native aluminum metal does not occur naturally. And humans have been actively smelting aluminum for only a little over 100 years. So the answer has to be along the lines that they "think" it is something else. What they confuse it with, I do not know.

So they may be mineral deficient, but aluminum eating has the potential for toxicity.

 

[Sanborn Chase]

Thank you, Mr. McNamara, for responding.
Aluminum trichloride is supposed to be quite pungent, which may mean something. I'm waiting on more observations to be made after rainstorms; the AlCl3 would go to aluminum hydroxide and hydrochloric acid I think, and that reaction is exothermic. Down at the level of a little squirrel nose that may be easily detected and seem delicious. More if my subjects will cooperate.
Incidentally, the fact that they go on mass migrations every few years and have a rather short lifespan in the wild may accommodate the sporadic nature of this activity.

 

[UsableThought]

Incidentally, the fact that they go on mass migrations every few years and have a rather short lifespan in the wild may accommodate the sporadic nature of this activity.

Mass migrations nowadays, as frequently as every few years? Do you have a source, whether four-footed or two? I was under the impression that migrations in modern times are less common than back when the squirrel population was so plentiful (as w/ bison, passenger pigeons, etc.) that changes in food supply, or birth rate in response to food supply, could cause such mass behavior.

I did find reports of a mass exodus in 1968 in the Northeast - see http://www.lib.umd.edu/blogs/univarch_exhibits/wp-content/uploads/univarch_exhibits/1968-squirrel-migration.pdf, which I learned about via this search hit; and a very brief mention of a 1998 migration in Arkansas at the end of this Delta FarmPress copy & paste article, "Massive squirrel migrations recorded in North America," comparing past & present. But nothing more than that. Do you still see such migrations where you are?

Also I had read that what migrating does go on today tends to be along quite short routes, e.g .a few miles? If so this would hardly compare to the very long routes many birds still follow today - which is the sort of thing I think most laypersons such as myself would automatically think of in terms of scope.

 

[Ygggdrasil]

Maybe they chew on everything, but it's only softer metals like Al or Pb where you can see the evidence.

 

[Sanborn Chase]

This:
During fall, squirrels may travel 50 miles (80 km) or more in search of better habitat. Squirrel populations periodically rise and fall. During periods of high populations, squirrels—especially gray squirrels—may go on mass emigrations. At such times many animals die.
From this:
http://icwdm.org/handbook/rodents/TreeSquirrels.asp