"Duck and Cover" - the KT extinction event

In a recent article in the GSA Bulletin, Robertson and collegues propose a thermal-sheltering hypothesis for animals that survived the K-T extinction event, 65 million years ago, when an extraterrestrial impact wiped out most terrestrial vertebrate groups (including the dinosaurs). Robertson et al.'s hypothesis argues that terrestrial vertebrates species that managed to survive the extinction event by either hidding underground or underwater. While this hypothesis may hold true for North American taxa. It is difficult to conclude if this hypothesis holds true for other parts of the world. The best K-T boundary fauna in South American (Tiupampa fauna of Southcentral Bolivia) contains a number of arboreal (tree living) mammals, and relatively larger bodied mammals.