Table 1.

PGLS model for explaining variation in sampling effort among primate species

Variable	Slope ± SE	t201
Geographic range size (km2)	0.347 ± 0.056	6.222***
Phylogenetic distance (My)	0.189 ± 0.729	0.260
Substrate use	−0.864 ± 0.155	−5.572***
Body size (g)	0.409 ± 0.158	2.597*

λ = 0.322; r² = 0.333. Phylogenetic distance is measured as phylogenetic distance from humans in millions of years. Substrate use is a four-state-ordered variable ranging from fully terrestrial to fully arboreal, with more arboreal species scored higher. *P < 0.05; ***P < 0.001.