Editing Bison (section)

== Reproduction ==
[[File:Bison with its young.jpg|thumb|A bison calf resting with its mother]]
Female bison ("cows") typically reproduce after three years of age<ref>{{Cite journal|last=Craine|display-authors=et al|date=2013|title=Precipitation timing and grazer performance in a tallgrass prairie|journal=Oikos|volume=122|issue=2|pages=191–198|doi=10.1111/j.1600-0706.2012.20400.x|bibcode=2013Oikos.122..191C }}</ref> and can continue beyond 19 years of age.<ref name=":1" /> Cows produce calves annually as long as their nutrition is sufficient, but not after years when weight gain is low. Reproduction is dependent on a cow's mass and age.<ref name=":1" /> Heavier cows produce heavier calves (weighed in the fall at weaning), and weights of calves are lower for older cows (after age 8).<ref name=":1">{{Cite journal|last=Hamel|first=Sandra|date=2012|title=Maternal allocation in bison: co-occurrence of senescence, cost of reproduction, and individual quality|journal=Ecological Applications|volume=22|issue=5|pages=1628–1639|doi=10.1890/11-2181.1|pmid=22908718|bibcode=2012EcoAp..22.1628H }}</ref>