title: Embryonic oxygen enhances learning ability in hatchling lizards.
abstract: BACKGROUND
  Producing smart offspring is an important fitness trait; individuals with enhanced cognitive ability should be more adept at responding to complex environmental demands. Cognitive ability can be influenced by conditions experienced during embryonic development. Although oxygen is necessary for embryonic development, availability can be limited within the nest environment because of substrate type, hydric conditions, and temperature. We do not yet understand, however, whether oxygen availability during embryonic development influences offspring fitness, especially cognitive ability. To address this question we incubated Mongolian Racerunner lizard (Eremias argus) eggs under hypoxic (12% O2), normoxic (21% O2), and hyperoxic conditions (30% O2).
  
  
  RESULTS
  Hypoxia not only slowed hatching time, but also resulted in constrained cognitive ability relative to hatchlings experiencing normoxic or hyperoxic incubation conditions. Oxygen did not influence hatching success, body size or sprint speed of hatchlings.
  
  
  CONCLUSIONS
  Oxygen availability during embryonic development has important influences on incubation duration and cognitive ability of hatchling lizards. This study provides the first evidence that oxygen availability during embryonic development can modify cognitive ability of oviparous reptiles.
authors.forename: Bao-Jun
authors.initials: BJ
authors.lastname: Sun
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Wang
authors.forename: David A
authors.initials: DA
authors.lastname: Pike
authors.forename: Liang
authors.initials: L
authors.lastname: Liang
authors.affiliation: Key Laboratory of Animal Ecology and Conservational Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China. duweiguo@ioz.ac.cn.
authors.forename: Wei-Guo
authors.initials: WG
authors.lastname: Du