Jelaskan Bison dari Taman Negara Yellowstone dalam bahasa melayu

Bison once numbered between 30 and 60 million throughout North America; Yellowstone is one of their last strongholds. Their populations had increased from less than 50 in the park in 1902 to 4,000 by 2003.

The park's bison population reached a peak in 2005 with 4,900 animals. Despite a summer estimated population of 4,700 in 2007, the number dropped to 3,000 in 2008 after a harsh winter and controversial brucellosis management sending hundreds to slaughter. APHIS has stated that with vaccinations and other means, brucellosis can be eliminated from the bison and elk herds throughout Yellowstone.