From Lehigh's website :
"Once fluid is impacted, they shed the front portion of the bullet into multiple petals that radiate outward away from the bullets initial trajectory path resulting in a massive energy spike. The bore diameter base of the bullet continues and penetrates deeply in a straight line."
I would think that since they are engineered to shed some petals initially, that this would then equate to a little less inertia to drive in deeper with whats left-over, when it comes to a more dense critter like a bear. I would *think* the preferred desire for a creature like a bear would be to have the mass of the entire projectile remain together in order to provide more inertia/momentum for the tissues to have to try to overcome, better gauranteeing that the bullet continues to freight-train on thru to the other side, especially if presented with a bone in the way.
Bears can have some reDONKulously thick bones! I have a Bear Humerus (upper arm bone) I found out in D13 that is 4" diameter AT IT'S THINNEST!!! Not that you'd be intentionally shooting at a bear humerus but if it were to move after the shot was fired, ya know, it'd be nice to know it had the maximum chance of pile-driving on thru such an obstacle by retaining ALL it's weight to do so, in order to retain maximum inertia/momentum to fight against the tissues trying to stop it. Yes?