A chemical commonly used for this is called mercaptin. The process of adding the stink is called stenching.
To interpret a barrage of information, sharks have developed a relatively large and complex brain...
I've heard that some dogs can smell if someone has cancer. Is this really true, or is it more like an urban legend?
How tiny stones inside our heads tell us which way is up...
Why don't tooth-brushing and mouthwash really help? Why makes garlic so persistently stinky?
What is black and white and very smelly all over?
Why does our body sniff rather than smell things?
Female lemurs on contraceptives smell different to potential mates than ones that are not.
Why are snake's tongues shaped the way they are?
Sometimes it seems like snakes have a sixth sense. You may call their "sixth sense" the vomeronasal system.