All farmyard animals I've observed seem to be able to fall asleep immediately after lying down, while humans typically take 10-20 minutes to fall asleep, but this can stretch into longer periods of time. Is there an evolutionary reason that we can't fall asleep on command? Or is it a consequence of having complex brains? Insomnia, even in lesser forms seems to negatively affect well-being. What do you think is the reason for sleep latency in humans /sci/?