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Sending Email Via Carrier Pigeon

This is the latest installment in a fun-with-math series called Back of the Envelope. Need help estimating something? Email DataLab.

Before you squawk at a DataLab post about a World War II-era method of communication, hang on. What will you do when the apocalypse hits, phone lines and the Internet go down, and you need to ask Brenda to collate those TPS reports from that last quality-assurance brain-storming session? And what will poor Brenda do when she doesn’t know what to do with those TPS reports? Poor you. Poor bloody Brenda.

That brings us to pigeons. According to the tech research group Radicati, email users send an average of 39 messages each day. Radicati also says that worldwide, there are about 4,116,000,000 email users (24 percent business, 76 percent consumer). Assigning one bird to each outgoing message means we’re going to need nearly 161 billion pigeons for one day’s worth of email.

But wait. We’ve assumed that emails never have more than one recipient. That’s wrong. And we’ve assumed emails are never sent across distances of more than 1,100 miles, which is about the most a pigeon can manage. That’s wrong, too. Pigeons would probably have to tag each other in and take breaks for some bread crumbs. You would also have to be pretty patient (Brenda, too), because pigeons fly at an average speed of 45 to 60 mph.

Our next question was, how much would an email weigh? That message from Paul to say that he brought doughnuts for the team (God bless Paul) might not weigh much, but what about that instruction manual Priya sent last week? We took an email attachment of 25 MB — Google’s maximum attachment size — and saw how it translated to pages printed and weight in grams. The results are below.

File Type Printed Pages Weight (in kg)
Word document 1,500 15
PDF 500 5
Average 1,917 19.2

Now, a drug-smuggling pigeon in Colombia found a 45-gram package (40 grams of marijuana and 5 grams of cocaine paste) just a bit too heavy. So, let’s say a pigeon can manage 40 grams. That would mean that for every email with a 25-MB attachment, you’d probably need about 480 pigeons. If just one in 50 emails sent has a such an attachment, we’d need to revise up our carrier-pigeon contingent from 161 billion to 1.698 trillion.

Either we’d need to start sending fewer emails, or else the Earth would need to be inhabited by 243 times more pigeons than humans to cope with an Internet failure. Of course, if the apocalypse does come, our emailing needs might change. Those TPS reports might not be a top priority.

Pigeons in numbers:

• You can apparently send a message via carrier pigeons for the low, low price of \$9.95.
• A pigeon named G.I. Joe flew 20 miles in 20 minutes, and in doing so communicated a message that saved the lives of more than 1,000 soldiers.
• According to the U.K.’s Pigeon Control Resource Centre, pigeons are the only nonmammal that can recognize themselves in the mirror, as well as recognize all 26 letters of our alphabet. (That last claim sounds particularly outlandish to me, but you can decide for yourself.)

Mona Chalabi is data editor at the Guardian US, and a columnist at New York Magazine. She was previously a lead news writer for FiveThirtyEight.