Editing American bison (section)

===Predation===
[[File:Canis lupus pack surrounding Bison.jpg|thumb|right|American bison standing its ground against a [[northwestern wolf|wolf]] pack]]
[[File:File-Grizzly bear on bison carcass near Yellowstone Lake;-Jim Peaco;-April, 2013;-Catalog 19070d;-Original IMG9750 (04985491-b01a-4c42-a31c-5e76447bb7f7).jpg|right|thumb|A [[grizzly bear]] feeding on an American bison carcass.]]
While often secure from predation because of their size and strength, in some areas, vulnerable individuals are regularly preyed upon by [[wolves]]. Wolf predation typically peaks in late winter, when [[elk]] migrates south and bison are distressed with heavy snows and shortages of food sources,<ref>{{cite web |url=https://peopleandcarnivores.org/what-do-wolves-do-in-the-winter/ |title=What do wolves do in the winter? |access-date=June 17, 2020 |archive-date=June 17, 2020 |archive-url=https://web.archive.org/web/20200617035145/https://peopleandcarnivores.org/what-do-wolves-do-in-the-winter/ |url-status=dead }}</ref> with attacks usually being concentrated on weakened and injured cows and calves.<ref name=BvW>{{Cite journal|url=https://academic.oup.com/jmammal/article-abstract/81/4/1128/2372815?redirectedFrom=fulltext|title=Wolf–Bison Interactions in Yellowstone National Park|first1=Douglas W.|last1=Smith|first2=L. David|last2=Mech|first3=Mary|last3=Meagher|first4=Wendy E.|last4=Clark|first5=Rosemary|last5=Jaffe|first6=Michael K.|last6=Phillips|first7=John A.|last7=Mack|date=November 1, 2000|journal=Journal of Mammalogy|volume=81|issue=4|pages=1128–1135|via=Silverchair|doi=10.1644/1545-1542(2000)081<1128:WBIIYN>2.0.CO;2}}</ref><ref>{{cite journal|last=Jung|first=Thomas S.|date=2011|title=Gray wolf (Canis lupus) predation and scavenging of reintroduced American bison (Bison bison) in southwestern Yukon|url=https://bioone.org/journals/northwestern-naturalist/volume-92/issue-2/10-07.1/Gray-Wolf-Canis-lupus-Predation-and-Scavenging-of-Reintroduced-American/10.1898/10-07.1.full|journal=Northwestern Naturalist|volume=92|issue=2|pages=126–130|doi=10.1898/10-07.1|s2cid=86100204|issn=1051-1733}}</ref> Wolves more actively target herds with calves than those without. The length of a predation episode varies, ranging from a few minutes to over nine hours.<ref>{{cite book|author=Mary Ann Franke|title=To save the wild bison: life on the edge in Yellowstone|year=2005|publisher=University of Oklahoma Press|isbn=978-0-8061-3683-7|page=[https://archive.org/details/tosavewildbisonl0000fran/page/199 199]|url=https://archive.org/details/tosavewildbisonl0000fran/page/199}}</ref><ref>{{cite book|author1=Douglas W. Smith|author2=Gary Ferguson|title=Decade of the Wolf: Returning the Wild to Yellowstone|date=November 1, 2006|publisher=Globe Pequot|isbn=978-1-59228-886-1|page=68}}</ref> Bison calves use five apparent defense strategies in protecting themselves from wolves: running to a cow, running to a herd, running to the nearest bull, running in the front or center of a stampeding herd, and entering a lake or river or other body of water. When fleeing wolves in open areas, cows with young calves take the lead, while bulls take to the rear of the herds to guard the cows' escape. Bison typically ignore wolves not displaying hunting behavior.<ref name="Wolf">{{cite journal |author=Carbyn LN |author-link=Ludwig N. Carbyn |author2=Trottier T |year=1988 |title=Descriptions of Wolf Attacks on Bison Calves in Wood Buffalo National Park |journal=Arctic |volume=41 |issue=4 |pages=297–302 |url=http://pubs.aina.ucalgary.ca/arctic/Arctic41-4-297.pdf |doi=10.14430/arctic1736 |access-date=August 16, 2008 |archive-date=June 26, 2012 |archive-url=https://web.archive.org/web/20120626174715/http://pubs.aina.ucalgary.ca/arctic/Arctic41-4-297.pdf |url-status=dead }}</ref> Wolf packs specializing in bison tend to have more males because their larger size than females allows them to wrestle prey to the ground more effectively.<ref>{{cite news |last=Smith|first=Doug |url=http://billingsgazette.com/news/state-and-regional/montana/bigger-is-better-if-you-re-a-hungry-wolf/image_109fa423-26ac-5ecd-a570-c9c37ae29445.html |title=Bigger is better if you're a hungry wolf |newspaper=[[Billings Gazette]] |date=March 1, 2009 |access-date=September 7, 2014}}</ref> Healthy, mature bulls in herds rarely fall prey.

[[Grizzly bear]]s are known to feed on carcass and may steal wolves' kills. Grizzlies can sometimes kill calves as well as old, injured, or sick adult bison, but direct killing of adult bison is rare even when grizzlies target lone and injured young individuals.<ref>David Maccar, 2010, [https://www.fieldandstream.com/photos/gallery/hunting/2010/11/amateur-photographer-captures-grizzly-bear-chasing-bison-down-highway/ Amateur Photographer Captures a Grizzly Bear Chasing a Bison Down a Highway in Yellowstone]</ref><ref name=BvsB>{{cite web|url=https://billingsgazette.com/outdoors/watch-now-yellowstone-grizzly-vs-bison-video-vaults-wyoming-man-to-prominence/article_db36934a-fd08-5e54-9387-e539f4e90af2.html|title=Yellowstone grizzly vs. bison video vaults Wyoming man to prominence|first=Brett|last=French|date=June 11, 2020|website=Billings Gazette}}</ref><ref>{{cite journal|author=Wyman, Travis|title=Grizzly bear predation on a bull bison in Yellowstone National Park|journal=Ursus|year=2002|pages=375–377|url=http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_13/Wyman_13.pdf|access-date=June 16, 2020|archive-date=October 11, 2017|archive-url=https://web.archive.org/web/20171011021901/http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_13/Wyman_13.pdf|url-status=dead}}</ref> Attacking a healthy bison is risky for a bear, who itself may be killed instead.<ref>Mary Ann Franke, 2005, ''To Save the Wild Bison: Life on the Edge in Yellowstone'', p.201, University of Oklahoma Press</ref><ref>Tom McHugh, 1979, ''The Time of the Buffalo'', p.213, University of Nebraska Press</ref>