Title: Natural Swarms in $\bf 3.99$ Dimensions

Abstract: The dynamical critical exponent $z$ of natural swarms is calculated using the renormalization group. To order $\epsilon = 4-d$, a novel fixed point emerges, where both off-equilibrium activity and mode-coupling inertial interactions are relevant. In three dimensions the critical exponent at the new fixed point is $z=1.3$, in fair agreement with experiments.