動物界世中之最62

Naked mole rat

圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Nacktmull.jpg/200px-Nacktmull.jpg

http://en.wikipedia.org/wiki/Naked_Mole_Rat
Typical individuals are 8–10 cm long and weigh 30–35 g. Queens are larger and may weigh well over 50 g, the largest reaching 80 g....
Naked mole rat is one of the two species of mammals that exhibit eusociality. They have a complex social structure in which only one female (the queen) and one to three males reproduce, while the rest of the members of the colony function as workers.

圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/8/8e/Hyenas_at_stolen_impala_kill.jpg/800px-Hyenas_at_stolen_impala_kill.jpg

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斑鬣狗（Crocuta crocuta）群體生活，一個群體大到上百隻，小到十幾只，每群的首領是一個體格健壯的雌性斑鬣狗。斑鬣狗的社會組織等級森嚴，覓食時“母首領”總能得到一塊最大、部位最好的肉食，而且這是理所當然的。因此，有人稱斑鬣狗群是母系社會。
　　當兩只性別不同的斑鬣狗碰到一起時，雄性總讓雌性走在前面。如果只有一塊肉，雄的會把它留給雌的。此外，雌性個體比雄性個體重很多，平均可多出6．6千克。