A peavey and cant hook look almost similar, having a slight difference in construction. Of course, that difference creates a fine line in terms of usage too. Despite that subtle difference, you can use them interchangeably, by the way.
Let me explain.
Both the tools have a lever or handle and a hook. The dissimilarity is at the end of the handle.
The peavey has a point on the handle end that is used to test the log for soundness, to split the wood, or sticking on the ground, etc. A peavey is preferred by the woodworkers to deal with larger logs.
You can use a peavey to split frozen logs effortlessly.
On the other hand, the cant hook has a small hook on the handle. So, basically, you are getting a stronger bite from the cant hook with the help of two hooks.
Typically you will want to deal with small or medium logs with a cant hook. However, you can also roll and move large logs using a cant hook, too—no hard rules.