When do hummingbirds sleep?

Hummingbirds are known for their high metabolic rate and energy requirements. They feed constantly throughout the day to maintain their energy levels. However, they do need to sleep, although their sleep patterns are quite different from those of other birds.

Hummingbirds typically enter a state of torpor during the night, which is similar to hibernation but is not as deep. During torpor, their body temperature drops significantly, their heart rate and breathing slow down, and they enter a state of reduced activity. This allows them to conserve energy when food is scarce or during cold weather.

Hummingbirds usually start entering torpor around sunset and wake up around sunrise. The duration of their torpor can vary depending on the species and the environmental conditions. Some hummingbirds may enter torpor for only a few hours each night, while others may stay in torpor for several hours or even the entire night.

It's worth noting that hummingbirds do not have a true "nighttime" in the same way that other birds do. Since they are most active during the day, their sleep-wake cycles follow a diurnal rhythm, meaning they are more active during the day and less active during the night.

So, to answer the question, hummingbirds sleep at night by entering a state of torpor, where their body temperature drops, their metabolism slows down, and they become less active. This helps them conserve energy and survive during periods of lower food availability or colder temperatures.