Ray Nayler’s “The Mountain in the Sea” delved into octopus consciousness with terrific results, but “The Tusks of Extinction,” a novella, is even better, with fewer unruly subplots. In “Tusks,” scientists have brought back long-extinct mammoths, which need guidance — so they put the mind of a long-dead elephant expert, Damira, into a mammoth’s body, so she can become their matriarch. But Damira soon finds herself in a familiar situation, caught in a clash with ruthless poachers.

Nayler excels at writing about ecosystems, nonhuman communities and the dilemmas of conservation. “Tusks” also includes a sharp focus on toxic masculinity and the sort of power trip that would drive a person into an extreme environment to slaughter a beautiful, irreplaceable creature. The result is both breathtaking and heartbreaking.