Our new paper on the evolutionary origins of viviparity was just published in the Journal of Experimental Zoology B! In this perspective piece, collaborator Matt Watson and I note that many of the evolutionary origins of viviparity occur at high elevations, which are cold and have lower oxygen availability. We advocate for research to study the impact of hypoxia on development of embryos and juveniles under hypoxia in both live-bearing and egg-laying species. The lizard above is Yarrow's spiny lizard (Sceloporus jarrovii), which is viviparous lizard that is found at high elevations. Check out the link to read the paper!