Evolution. Parasites make scaredy-rats foolhardy.
Zimmer
C
C
D000818:Animals; D001522:Behavior, Animal; D005075:Biological Evolution; D005239:Fear; D005260:Female; D006801:Humans; D008297:Male; D010551:Personality; D051381:Rats; D014122:Toxoplasma / Q000502:physiology*; D014124:Toxoplasmosis, Animal / Q000469:parasitology / Q000523:psychology*; D016781:Toxoplasmosis, Cerebral / Q000469:parasitology / Q000523:psychology*