^ True enough. ^^() I suppose telling them the truth, or at least most of the truth, would be their best shot....
Although really, rats live for, what, six years at the most, in captivity? *checks wiki* Between two and five years, averaging three. Not knowing how old David's rat already was, or how much time passed between his Nothlit-age and the end of the war... if he survived meeting Rachel at one last time (which I have my personal arguments against ^^()) he was still prolly a senior citizen rat by the time any of the Animorphs became celebrities. (Assuming about equal time between each book, he'd have spent about a year and three quarters as an adult rat by the end of the war...) I don't honestly know what the chances would be of his parents finding him before a predator got him, or he died of old age.