Bold Seagull
strong and stable with me, or...
ITS INCREDIBLY HARD. Have you tried breaking into one?
Their shells are strong enough that they have been known to withstand bullets, dogs and even alligators.
Now, the tortoise shell does have some weaknesses as honey badgers have been noted ripping and clawing their way through these shells - but the honey badger isn't in this group so that battle will have to wait
We can start the 'hard' debate early I suppose. The hardest animal is shirley the one that is prepared to fight, against the odds, take on an opponent in all likelihood it could lose to. That is hard. Having a shell is not hard, that's just a shell. Unless I've missed an episode, I've not seen a tortoise go batshitmental taking on all comers to fight for the sake of it...