Are you a dog person? Maybe you have one at home and enjoy taking it for walks and curling up with it on the sofa.  Personally, I'm not that kind of person – for me they're aggressive, smelly animals that need constant care and lack the independent nature and intelligence that cats have. But given the life-saving skills that some dogs possess, maybe I should give them a second chance. 

To some a perfect pooch might be one that looks cute, is loyal and sits when it's told but that's about it – it's just a pet. But to really be man's best friend, they need to do something useful. Some breeds that have amazing sense of smell are put to good use as sniffer dogs or detection dogs, and are trained to use their senses to detect substances such as explosives and illegal drugs. You'll often see them at airports or working with police out on the streets.

Other types of working dogs include guide dogs, hearing dogs and mobility dogs all providing a life-saving service to their owners. Some dogs can alert emergency services when their owner has a seizure.  And there are clever canines that have been trained to provide affection and comfort to people in hospitals, retirement homes or schools and to people with autism.

New uses for dogs are being discovered all the time. Dr Claire Guest is CEO of Medical Detection Dogs, she says "although the dog has a fluffy coat and a waggy tail, he is in fact a highly sophisticated bio-sensor. You know, evolution has given him this highly sensitive nose, going down to parts per trillion."

It's this incredible ability that has led to the UK's National Health Service assessing whether dogs can be used to detect early stage prostate cancer - vital for improving survival rates.

The dogs - usually from the gundog breed, such as labradors and springer spaniels - are taught to detect a sample of urine from a patient with prostate cancer.

It's also managed to train dogs to detect changes in blood glucose levels in people suffering from type 1 diabetes. One patient, who has one of these medical alert assistance dogs, told the BBC that "in the three and a half years we've been together, he has alerted and potentially saved my life 3,500 times. And he does it all for a dog biscuit."

To save a life for a dog biscuit seems a small price to pay so maybe I should have more admiration and respect for our four-legged friends – maybe cats aren't so smart!

词汇表

a dog person 喜欢狗的人
aggressive 好斗的、霸道的
life-saving 能挽救生命的
give them a second chance 给它们第二次机会，比喻重新考虑
pooch （非正式）狗
loyal 忠诚的
man's best friend “人类最好的朋友”，是对狗的昵称
sense of smell 嗅觉
sniffer dogs 嗅探犬
substances 物质，材料 
guide dogs 导盲犬
seizure（疾病的）发作
canines 犬科动物
affection 爱、友好之情
autism 自闭症、孤独症
waggy 爱摆动的，不停摇摆的
bio-sensor 生物感应器
prostate cancer 前列腺癌
type 1 diabetes 第一型糖尿病
medical alert assistance dogs 医疗警报援助犬
a small price to pay 微不足道的代价
four-legged friends “四条腿的朋友”，对狗的昵称