[3] Much of his work has been on the phylogenetics and functional evolution of mammals, especially Carnivora[4][5] and Creodonta,[6] on the correspondence between phenotypic and genetic differentiation,[7] on the role of functional traits in structuring mammalian communities,[8] and on the evolution of multivariate quantitative morphological traits.
[9] With lead author Jason Head and other co-authors, he helped describe the giant fossil snake Titanoboa and the associated methods for estimating paleotemperature from the size of extinct reptiles.
[10][11] Polly received a BA from the Plan II Honors program at University of Texas at Austin in 1987[12] and a PhD in Paleontology from the Department of Integrative Biology at University of California, Berkeley in 1993 for his work on the phylogeny of creodonts.
[16] During Polly's term as SVP president, US President Donald J. Trump and Interior Secretary Ryan Zinke downsized two national monuments that protect vertebrate paleontological resources, Grand Staircase–Escalante and Bears Ears national monuments.
[17] With Robert P. Guralnick and Allen Collins, Polly started one of the first 50 websites in the world in 1993, the University of California Museum of Paleontology site.