From The Vault

Perk Death Sense Fallout Tactics requirements: Level 4, Intelligence 5 Deathclaws only ranks: 1 benefit: +20% Perception while in the dark +25% bonus to detecting Sneaking enemies

Death Sense is a Fallout Tactics Perk available only to deathclaws. So far it hasn't appeared in any other game.

You have developed superior senses. The perk gives you a +20% bonus to Perception while in the dark and a +25% bonus to detecting enemies using the Sneak skill.