Kendall and Kylie Jenner share secrets during game of 'Which Sister': Guess who ignores the other's texts!

The Kardashian-Jenner ladies are known for being practically glued to their phones, so one might expect them all to be major texters.

Wrong. Kendall and Kylie Jenner played a game of "Which sister?" for Glamour.com, and shockingly, one of them isn't into the whole texting thing at all.

In fact, she never responds to her sister's text messages! Check out the video above to find out who and to discover a few other sibling secrets.

Kendall, 19, and Kylie, 17, filmed the video during an interview with Glamour about their new Top Shop collection.

Though they didn't always see eye to eye during "Which sister?", the pair seemed to be as close as ever. But about those unreturned text messages…