PROBLEM TO BE SOLVED: To provide a transgenic nonhuman mammal that has new characteristics.SOLUTION: A transgenic nonhuman mammal with an extended life is provided by introducing a gene encoding a p85 regulatory subunit &bgr of a modification phosphoinositide-3 kinase that does not activate Akt(serine/threonine kinase) into a nonhuman mammal. A protein comprising an amino acid sequence represented by a sequential identification number 2 is included as the p85 regulatory subunit &bgr. Preferably, the nonhuman mammal may be a rodent, e.g., a mouse. It may be gigantic one in addition to life elongation.