Well I just ate

[quercus alba]

the toughest ribeye ever. Must have been off an old hyena. the one I cooked for my wife was melt in your mouth tender. Came out of the same package. Must have been two different hyenas.

[Big Muddy]

QA, same thing happened to us a couple of weeks ago.....we buy Black Canyon beef, which is usually really tender....however, those steaks could have been better used as boot leather. ;)