Prairie dogs don't just have a call for "danger" — they have one signature set of frequencies and tones for "human," another for "hawk" and a third for "coyote." They can even differentiate between coyotes and pet dogs.
Two very similar types of Parkinson's Disease can be differentiated by asking whether the patient can ride a bicycle, a cheap and noninvasive diagnostic test.
Two very similar types of Parkinson's Disease can be differentiated by asking whether the patient can ride a bicycle, a cheap and noninvasive diagnostic test.