Here's why:
* The vowel sound in "owl" is similar to the sound in the word "out".
* Long vowel sounds are typically associated with a single vowel letter followed by a silent "e" at the end of the word (like "cake" or "kite").
* Short vowel sounds are often found in words with one vowel letter followed by a consonant (like "cat" or "dog").
Therefore, the "o" in "owl" has a short vowel sound.