A990, Rat Strain

**Semantic type:** Mammal

**Definition:** Resistant to Cysticercus. Susceptible to estrogen-induced mammary and adrenal tumors. Good reproduction. High open-field defecation (2/12, males, 3/12 females) and low ambulation (11/12), Harrington (1972). Low wheel activity (12/12) (Harrington 1971b). Aggressive towards handlers (Harrington 1981).