If no one follows, the scent quickly fades.

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However, no cover was provided and fox scent, in the form of faeces and urine, was scattered liberally around, mimicking conditions on the ground.

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"Once they learn to pick up the scent of boar, they no longer want to chase anything else, " he says.

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No one has a crystal ball, but investors can pick up the scent of trouble early if they are paying attention.

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