Snawler eggs are by far the hardest egg in Ark. Experiments have been done by the Science and Research Center where they have dropped Snawler eggs; they found that 100% of them do not break (with no margin of error). Perhaps this is what has ensured the Snawler's survival. However, Snawler eggs that have been dropped multiple times hatch exceptionally early; most premature Snawlers die. So, it's best not to drop these eggs, but don't worry if you do.
Snawlers have an extremely hard shell that is impenetrable. Funny enough, Snawlers also travel very quickly. They have an extremely slick underbody which allows them to "slide" across any surface. Sometimes playing the game "Kick a Snawler" is rather entertaining! Even better, Snawlers don't mind!