They are fairly squishy at first, until you gain a few levels for hp and invest a point in the armor passive. I found it also helped once your party can cast some buffs and debuffs, like blind and +con.
I play stalker so pet has +1 armor when near the watcher but I'm still using the wolf mainly as a flank attack. In off-tank situations I have Xoti cast +5 con on him.
Pet does go down occasionally still (i'm on PotD they hit hard) if caught in a bad spot, and has no way of escape yet or play dead.
If pet gets to low health (and is not engaged!), don't be afraid to pull him away or behind you, let him play guard dog in case something rushes past the frontline. Better have him alive and not suffer bond debuff and he can still help mob up the fight. Also don't have him rush in headfirst, sneak in from the sides once enemies are already engaged and get the -10 deflect from Flanked.
Atm my wolf can only handle 1 enemy on him, maybe 2 if there are heals still available. That said it helps that i'm multiclassed chanter and using skellys to take some of the hits.
I guess the bear/boar are the tanky ones, wolf has good damage and little squishy, but so far it hasn't been a problem once you get used to the micro, and Heal Pet/Play Dead will help a lot.