Mice or rat(s)?

Dem's mice.

I understand both mice and rats are used.
When the paper refers to rats they mean a Rat.
When the paper refer to mice they mean mice.

Adult mice are much smaller than adult rats (Fig. 1). Adult mice weigh about 30 grams, and fancy mice tip the scales at about 50 grams. Adult mice have bodies that are 3-4 inches long with 3-4 inch tails.

Adult rats are far heavier and longer: they can weigh ten times as much, averaging 350-450 grams for females and 450-650 for males (with an overall range of 200-800 grams). They have 9-11 inch long bodies and 7-9 inch tails (ref).

Thank you.