  It is proved that an endomorphism $\varphi$ of a hyperbolic group $G$
satisfies a H\"older condition with respect to a visual metric if and only if
$\varphi$ is virtually injective and $G\varphi$ is a quasiconvex subgroup of
$G$. If $G$ is virtually free or torsion-free co-hopfian, then $\varphi$ is
uniformly continuous if and only if it it satisfies a H\"older condition if and
only if it is virtually injective. Lipschitz conditions are discussed for free
group automorphisms.
