The evolution of gestation length in eutherian mammals.

Eutherian mammals exhibit considerable variation in their gestation lengths, which has traditionally been linked to variation in other traits, including body mass and lifespan. To understand how gestation length variation, including its association with body mass and lifespan variation, changed over mammalian evolution, we conducted phylogeny-informed analyses of 845 representative extant species. We found that gestation length substantially differed in both whether and how strongly it was associated with body mass and lifespan across mammals.

The evolution of gestation length in eutherian mammals.

Gestation length, or the duration of pregnancy, is a critical component of mammalian reproductive biology. Eutherian mammals exhibit striking variation in their gestation lengths, which has traditionally been linked to and allometrically scales with variation in other life history traits, including body mass and lifespan. How the phenotypic landscape of gestation length variation, including its associations with body mass and lifespan variation, changed over mammalian evolution remains unknown.