in the last week my dog has started being extra nice to my friend when we go to her house. Keeps sniffing her breath and pushing his head at her stomach and wants to snuggle up to her all the time.
She just told me tonight she's 5 weeks pregnant. What a clever boy he is!

He can smell the changes in hormones.

They're extremely intelligent. As the Secret Life of Dogs program that was on last week, that lady's dog could smell she had breast cancer.

Remember The Cat Of Death from a couple of years back

It's no more intelligent than me smelling fresh baked bread & feeling happy or smelling off milk and avoiding it.

Dogs are an intelligent animal and can be trained, but lets not attribute olfactory sense to brain power.

My cat can detect when my mum is about to have a certain auto-immune attack. She's only ever very affectionate to me (and I don't live at home anymore), but a few hours before an attack hits. she curls up close to my mum, and she always stays with her until it's over.

Dogs never cease to amaze my, what an amazing story, thanks for sharing!

Voice of reason!!