  We propose to create and stabilize long-lived macroscopic quantum
superposition states in atomic ensembles. We show that using a fully quantum
parametric amplifier can cause the simultaneous decay of two atoms and, in
turn, create stabilized atomic Schr\"{o}dinger cat states. Remarkably, even
with modest parameters these intracavity atomic cat states can have an
extremely long lifetime, up to \emph{4 orders of magnitude} longer than that of
intracavity photonic cat states under the same parameter conditions, reaching
\emph{tens of milliseconds}. This lifetime of atomic cat states is ultimately
limited to \emph{several seconds} by extremely weak spin relaxation and thermal
noise. Our work opens up a new way toward the long-standing goal of generating
large-size and long-lived cat states, with immediate interests both in
fundamental studies and noise-immune quantum technologies.
