Okay
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Think of it this way: wolves are naturally digitigrade (meaning they walk on their toes and not the calcaneus/"heel" like humans do). But because the toes are not as good for balance, wolves are quadropeds meaning they walk on four legs to retain balance. Anthros are mythic creatures so their anatomies are obviously not as...scientifically correct...but you, as an artist, can at least fool your audience into believing that your anthro follows the laws of physics. Because most anthros are digitigrade and ALSO bipedal (walks on two feet), it creates balance and center of gravity issues. The top part of the body is much heavier than the bottom making the anthro unstable. Therefore, to compensate, slighting larger tails, larger feet, human knees, and a slightly slouched posture are necessary to make your anthro believable.
Check out part three of my tutorial. It might explain some of this better. Perhaps I will make another part of the tutorial that explains all about center of gravity, posture, and weight distribution. Stay tuned and I hope this helps. Also, I might go into further detail about feet proportions.
~D