Yes, they do! Half of the time that infants sleep is spent as REM (rapid eye movement) sleep.
In fact, babies spend twice as much time in REM as adults do. That amount of REM or “active” sleep makes a lot of sense because it encourages the “plasticity” or responsiveness to environmental input that helps shape important brain networks, including those that govern sensory processing and motor control. For a developing young brain that relies on that input to create neuronal connections and networks, supporting plasticity is highly beneficial.
Another characteristic of REM sleep, especially in the very young, is how restless it can seem. Myclonic twitching (e.g., jerky limb movements), which some researchers believe may be related to the development and mapping of motor skills, is both common and normal, as are apneas (very brief cessation of breathing – from 3 to 10 seconds) which typically occur after a sigh, a body movement or during wake-sleep transitions.
So, for all those bleary-eyed parents of newborns who can’t wait for the day when their baby sleeps through the night, hopefully, there’s a little bit of comfort in knowing that their infant’s chaotic sleep pattern is actually part of their hugely important work to develop the brain circuitry that will carry them through life.