The wolf damage mystery

[R.T.]

In the Monster Manual, there are 3 wolves: Winter Wolves, Worgs, and normal Wolves. For some reason, the damage of the Winter Wolf and the Worg seems to be too high:

Wolf: Str 13 -> 1d6+1

Winter Wolf: Str 18 and Large Size -> 1d8+6 (shouldn't this be +5?)
Worg: Str 17 -> 1d8+4 (shouldn't this be +3?)

There's nothing in the description text indicating where this "extra" damage comes from. No special feats either. And there's nothing in the official errata.

The only thing I can think about is that the creature is a magical beast, or WoTC wanted to reflect the added danger these wolves pose over their "normal" cousins.

Any ideas?
Probably something simple I'm overlooking...

 

[HeavyG]

Since they use only one natural weapon, their strength bonus to damage is multiplied by 1.5 as if they were using a two-handed weapon.

Edited to correct a typo. Twice.

 

[R.T.]

Cool. I thought it would be something simple. Thanks for the quick clarification!