Coins kill condors.
June 9, 2009 12:04 PM   Subscribe

This morning we saw a sign at Grand Canyon about a female condor that died from zinc poisoning following the ingestion of too many coins (presumably, it had been looking for sources of calcium in order to produce harder eggshells). Dad immediately declared that the given cause of death is untrue, since zinc in coins is inert. Prove him wrong, hive mind!

Dad's no avian biologist, and while I know what happens with zinc once it's in your system, I don't know much on the subject of what happens to coins after they're swallowed. It's hard to look for relevant articles on an iPhone, that's why I'm appealing to you for help. Money and dignity are at stake.
posted by halogen to Science & Nature (16 answers total) 1 user marked this as a favorite
Coins have traditionally been considered relatively inert in their chemistry. A dime (17 mm) or a penny (18 mm) will usually pass through the intestinal tract if there is no hold up in the pharynx or esophagus.[2] In 1982, the copper penny (95% copper, 5% zinc) was replaced by the zinc penny (2.4% copper, 97.6% zinc). The zinc results in chemical reactivity including the development of gastric erosions.
From here

Several other sources also suggest that pennies made after 1981 can be dangerous to humans and pets.
posted by Nothing at 12:12 PM on June 9, 2009

The relevant section from the Wikipedia article on zinc; doesn't mention condors, but does mention other animals.
posted by Halloween Jack at 12:14 PM on June 9, 2009

Read the article here.

If you scroll down to the related links section there are multiple scientific studies that discredit dad's theory.
posted by bradly at 12:15 PM on June 9, 2009

As others have posted, coin ingestion can be a serious problem in humans. Although the avian digestive system is very different than the mammalian one in many ways, they still use a hydrochloric acid-based gastric juice similar to that found in mammals. I imagine, then, that the sign was pretty accurate.
posted by jedicus at 12:16 PM on June 9, 2009

Also several sources, including this one suggest that birds in general, and condors in particular, have more acidic stomachs than mammals, making it even more likely that a slightly worn or uneven copper coating would not protect the zinc from dissolving.
posted by Nothing at 12:17 PM on June 9, 2009

Zinc is well known to be toxic to birds. I keep a flock of parrots and this is one of the main issues in finding a suitable barrier for an aviary enclosure.
posted by torquemaniac at 12:18 PM on June 9, 2009 [1 favorite]

Merck has a semi-useful summary of zinc toxicosis in animals.

...and as far as the copper goes, keep in mind that birds have crops, which rely on mechanical abrasion. Which will tend to strip the copper right off a penny in relatively short order, exposing the zinc.
posted by aramaic at 12:23 PM on June 9, 2009

Gold is famous for it's inertness, yet it's an effective treatment for rheumatic diseases and has potential serious side effects.
posted by neuron at 12:43 PM on June 9, 2009

...and as far as the copper goes, keep in mind that birds have crops, which rely on mechanical abrasion.

Not to mention gizzards, which function like ball mills to grind the hard parts of the food they swallow.

Birds will often seek out stones to put into their gizzards to make them grind efficiently, which is what I'd guess these vultures are doing when they consume pennies. And then the penny would sit in there indefinitely, putting out finely ground zinc particles that could be digested and absorbed.

I have often wondered how they avoid getting toxic rocks in there-- maybe pennies resemble some local variety of flint the birds have adapted to over the years, or maybe the previous composition of the penny was tolerable or even desirable.
posted by jamjam at 12:57 PM on June 9, 2009

posted by jamjam at 1:02 PM on June 9, 2009

Longer article about condors and the threats they face. Condors will eat random things like bottle caps and coins, and one of the biggest threats is lead poisoning. Long paper on condors and poisoning. Based on that paper, death from zinc toxicity is rare in condors compared to things like power lines. More have died from copper poisoning, actually.
posted by gingerbeer at 1:09 PM on June 9, 2009

My son swallowed a nickel a couple of months ago... which came right back up. Our pediatrician immediately asked if we were absolutely positive it wasn't a penny, because that would have meant an immediate visit to the ER. She then sent me this link via email.
posted by zarq at 1:48 PM on June 9, 2009

I have had a very similar conversation with my dad - him determinedly asserting that zinc is inert, and me insisting that all the research I've done about bird care says that it is poisonous to them. thanks for posting this - it's good to know I'm not the only one! Is your dad an engineer or chemist, by any chance?
posted by 5_13_23_42_69_666 at 4:56 PM on June 9, 2009

dad - him determinedly asserting that zinc is inert

Solid sheet-zinc laboratory benchtops were once state of the art, I've been told.
posted by jamjam at 5:27 PM on June 9, 2009

Response by poster: Almost a year late in replying to 5_13_23_42_69_666, but yeah, dad's a physical chemist.
posted by halogen at 3:09 AM on April 12, 2010

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