肯亞有研究發現寄生蟲弓蟲會改變幼年斑鬣狗的行為，減低了牠們對捕獵者獅子的警戒心，被捕食的機會增加四倍，但到了約一歲這種改變就會消失。研究指大概有三分之一的幼年斑鬣狗及八成的成年斑鬣狗曾被弓蟲感染。

Research in Kenya found some that spotted hyenas cubs are infected by the parasite Toxoplasma gondii and have behavioural change. These cubs are less alert to their predators, the lions and are four times more likely to be killed compare with healthy cubs. However, this behavioral change will disappear after the cubs turned one year old. the research also showed around 1/3 of the spotted hyenas cubs and 80% of adults have been exposed to this parasite.

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