Traits only exist if you own Bob’s Tall Tales and can use the Gene Scanner. Once you can scan a creature, the question stops being “which trait is strongest” and becomes “does this trait fit what I keep this creature for”. A bonus that helps a boss army can be a liability on the mount you ride every day.
Check the prerequisite first
Traits were added to ARK: Survival Ascended with the Bob’s Tall Tales content, and the Gene Scanner — the tool that lets you see and manage them — requires that DLC. A trait is a passive bonus attached to a creature; a reroll means replacing it rather than living with it.
So before any keep-or-reroll decision, confirm two things: the DLC is installed on your game, and you can actually run the Scanner. Without them there is nothing to evaluate. This is also an Ascended-only system — do not go looking for trait menus in the older ARK: Survival Evolved, which is a separate game covered in our Ascended vs Evolved comparison.
Keep or reroll by the creature’s job
| What the creature is for | Keep | Reroll away |
|---|---|---|
| Breeding stock | Clean, inheritable bonuses with no downside | Anything that carries a penalty into the line |
| Boss and Alpha team | Damage that applies to bosses and Alphas | Bonuses that only help against ordinary wild creatures |
| Gathering and utility | Reduced resource or stamina costs | Combat-only bonuses that never trigger |
| Transport and travel | Movement or nighttime stamina savings | Situational damage you will not use |
So read the row for the creature’s actual role, not the trait’s headline. A gathering mount gains nothing from a boss-damage trait, and a breeding parent passes on its downside as readily as its upside. Our breeding guide and mutations guide cover how traits sit alongside the rest of inheritance. If you are imprinting the creature too, the imprinting guide is the other half of that setup.
Trade-off traits: when a bonus is a trap
The clearest example is the boss-slayer trait: it adds damage against Alphas and bosses but reduces damage against everything else. Trait databases list it as the classic “CombatMax” style effect, and it is the reason a blanket “keep every good trait” rule fails.
The condition to keep it is narrow. It belongs on a creature that exists to fight bosses and Alphas and does little else. On a general-purpose mount, everything you attack is “everything else”, so the penalty is active almost all the time and the bonus almost never. Reroll it there. The same logic applies to any trait with a plus and a minus: check which target type you actually fight most, then decide.
Stacking and tiers change the call
Trait databases annotate effects with a tier and a stack limit, so the same trait is not equally valuable at one copy and at its maximum. Before you reroll, check whether the bonus can stack and what tier you are holding; a low-tier copy of the right trait may be worth replacing, while a stacked one is worth keeping even on a secondary creature.
Because the trait list ships with DLC updates, the exact effects and percentages can change between versions. Verify against the table for your current build rather than treating any published list as permanent — the keep-or-reroll logic above holds regardless of which numbers are attached.