Now Dr. White and his colleagues are following up with experiments to understand what might be slowing down aging in the old mice. “We’re hunting the hows and whys,” he said.

Baby rats look quite different from adult mice. “A baby rat will still be twice as big as a mouse,” Corrigan explains. Another key difference: Baby rats have giant heads, he notes, like ...

Some common mice colors are white, brown and grey. ... Baby mice are also called pups. Pet mice can live up to six years, while wild mice usually only live around 1 to 2.5 years.

They took baby mice from their mothers at 21 days of age, right after weaning. Some of the young mice were put in typical laboratory conditions, living in a cage with three other mice.