Monkey struggles to be heard London - Arabstoday Despite looking like he is shouting as loudly as possible, this mandrill is obviously not getting through to his hard-of-hearing friend. Leaning in with a hand over his ear, the male mandrill on the right is clearly struggling to understand what his boisterous friend is attempting to say. And with his mouth wide open and teeth bared - including two fearsome looking incisors - it's clearly frustrating for his talkative pal. These stunning images of the colourful mandrills were taken at Jerusalem Zoo recently by keen amateur photographer Olga Shiropaeva, 56, who is from the Czech Republic. Mandrills are the most colourful mammals in the world.They mainly live in dense rainforests and coastal forests and live in groups of up to 600 individuals in the wild. They are the world's largest monkeys and are usually found in the tropical rainforests of west Africa.