It is estimated that two-thirds of all mammal genera and one-half of all mammal species weighing at least 44 kilograms (97 lb) have gone extinct in the last 50,000 years.
據估計，三分之二的哺乳動物，屬單的一半的哺乳類動物體重至少44千克（97磅）的在過去5萬年滅絕。