The smell of vomit is widely considered to be one of the worst in the world, and may induce nausea in anyone nearby. While this may be simply a reaction to a malodorous aroma, it is possible that the body has a subconscious reaction to the smell or sight of the vomit itself. Because of the possibility that something the sick person has consumed has made them ill or poisoned them, your body may chemically decide to rid itself of potentially poisoned contents as well. In groups of apes, group or sympathetic vomiting has been observed after one animal becomes ill after eating. Since the other animals in the tribe have likely eaten the same things, sympathetic vomiting may be used as a survival tactic.

The cow enters the gated feeding area. While the cow is eating, a small bucket automatically swings into place at the back of the cow, moving gently upwards and downwards, massaging her escutcheon – a nerve which stretches between the cow’s vulva and udder. This nerve triggers the urine reflex, causing the cow to urinate. The urine is collected in the CowToilet reservoir and is then extracted and stored separately.

While talking Jethro on his daily walk I conducted a study of his sniffing and urination patterns. To learn about the role of urine in eliciting sniffing and urinating, I moved urine-saturated snow ("yellow snow") from place-to-place during five winters to compare Jethro's responses to his own and other dog's urine. Immediately after Jethro or other known males or females urinated on snow, I scooped up a small clump of the yellow snow in gloves and moved it to different locations. For some reasons passers-by thought I was strange and generally left me alone. Moving yellow snow was a useful and novel method for discovering that Jethro spent less time sniffing his own urine than that of other males or females.