When You Hear Hoofbeats Look for Horses Not Zebras

Hilton Read? Theodore E. Woodward? Ele and Walt Dulaney? Harley S. Smyth? Anonymous?

Dear Quote Investigator: In medicine the symptoms of a patient are often compatible with a variety of ailments. A skilled diagnostician will use probabilistic reasoning when deciding which ailment is the most likely. Bayesian inference first highlights common maladies instead of rare ones. Here are three versions of a germane saying:

  • When you hear hoofbeats look for horses not zebras.
  • If you hear hoof beats in the distance don’t expect a zebra.
  • When you hear hooves think of horses before zebras.

Admittedly, these adages work best outside of a zoo and on a non-African continent. Would you please examine the provenance of this saying?

Quote Investigator: The earliest published evidence located by QI appeared in the “Arkansas Gazette” of Little Rock, Arkansas in October 1962. Emphasis added to excerpts by QI: 1

The father of a young man who was there reports that at the University of Arkansas School of Medicine this week a doctor surrounded himself with about a dozen students and sought to go to the heart of proper diagnostic procedure.

In the end he summed up good diagnosis this way: “When you hear hoofbeats in the night, look for horses — not zebras.”

The passage above occurred in a column called “Our Town” by Charles Allbright, but the participants were unidentified.

An earlier origin for the saying has been suggested. However, the claim is weakened by a multi-decade delay. For example, a variant statement has been ascribed to Dr. Theodore E. Woodward circa 1940s. Evidentiary support appeared in the 1980s. See the citations further below.

This article presents a snapshot of current knowledge, and future researchers may discover material that alters the ascription.

Here are additional selected citations.

Continue reading When You Hear Hoofbeats Look for Horses Not Zebras


  1. 1962 October 5, Arkansas Gazette, Section: Sports and Markets, Our Town by Charles Allbright, At First, Anyway, Quote Page 1B, Column 1, Little Rock, Arkansas. (GenealogyBank)