The endangered Saimaa ringed seal is an Ice Age relict living in the highly labyrinthine Lake Saimaa, Finland. The newly published work shows that although individual seals have greatly reduced genetic variation, the loss of variation has been complementary, preserving the adaptive potential of the whole population.The endangered Saimaa ringed seal is an Ice Age relict living in the highly labyrinthine Lake Saimaa, Finland. The newly published work shows that although individual seals have greatly reduced genetic variation, the loss of variation has been complementary, preserving the adaptive potential of the whole population.