The only thing more cute than a little tiny animal is a little tiny animal that’s sleeping. I mean, COME ON! How could anyone argue with that?!
What about the tiniest of tiny—say, hummingbirds? Those little cuties work so hard during the day, flapping and buzzing around. They’re really extraordinary little creatures.
So how are they able to zip zing around every single day? How can they get so much energy in a night’s rest?
Everything you wanted to know about wee little hummingbirds and their sleeping habits is right here. And once you learn about the details, make sure to gawk at a few photos, because it’s AWESOME!
Hummingbird Energy Expenditure
Hummers basically spend their entire day using up energy. They are constantly moving around, save for a few resting moments here and there. It’s hard to fathom how intensely their bodies are working. Let’s put it in perspective.
- On a given day, a hummingbird’s heart rate can measure at 1,260 beats per minute! Ours ranges around 60-100 beats per minute, depending on how in shape we are. Can you imagine that itty bitty heart pumping a million miles an hour? Me either.
- In a single resting minute, they take about 250 breaths. Humans average 12-20 breaths per minute, and it makes me lightheaded to imagine breathing any more than that.
- In a single second, North American hummers average 53 wing beats in normal flight. And humans, well we can’t fly.
All those energy expenditures require vast amounts of fuel to power them. Because of this, hummers intake about half to eight times their body weight in nectar per day. If the average human had the same crazy metabolism, they would have to consume 285 pounds of meat to maintain their body weight.
In addition to fuel, they also need sleep. Good, solid sleep, that doesn’t waste any energy.
Wait, waste energy? I thought sleep was supposed to create energy.
Even while sleeping, bodies burn calories. Tally up those calories across several hours of sleep and it starts to add up. Those are calories that hummers simply can’t afford to spare, especially when they are not consuming food (unless they could sleep fly. If you know any birds that do this, please let me know because I’ll have some serious research to catch up on.)
During the day, hummers constantly eat food. They have to do this basically just to stay alive for the day. They burn so many calories and if they don’t replace them, they’ll perish. Since they don’t eat at night, they can’t risk wasting any precious calories.
So how do they manage to restrict their energy expenditure at night? That’s where their unique sleeping habits come in!
Hummingbird Sleep Cycle
Hummingbirds are on the go from about dawn to dusk. After dusk, they spend all their time sleeping. No flying, no eating, just sleeping. Sounds nice, right?
When nightfall approaches, they start to wind down and prepare for their nights sleep. They search out a safe place to perch. They are indiscriminate of potential sleeping quarters, as long as they will be safe—usually a tree branch of sorts. If it’s breeding season, the mother will spend her night in the nest with her babies. For non-mothers, often you might find them hanging upside down like bats wherever they’ve chosen to bed. If perching, their body relaxes and their heads lull backward, looking similar to your dad after Thanksgiving dinner, conked out in the recliner.
They have to find a sleeping area about a half hour before nightfall so their bodies can settle and prepare for intensely deep sleep. This sleep is called torpor.
Torpor
If a hummingbird’s internal processes worked the same at night as they do during the day, they would waste all their energy trying to keep warm, breathing, and maintaining their metabolism. The solution to this is either to wake up and eat (often) or slow these processes down so they don’t use as much energy.
Hummingbirds do the latter, which puts them in a state of torpor.
Torpor is a deep sleep that is similar to hibernation. It doesn’t happen over long periods of time, like hibernation, but the concept is very similar. Essentially, it’s a way to conserve energy.
When a hummingbird enters torpor, their heart rate drops down to roughly 50 beats per minute—a far cry from 1200 during the day! Their metabolism drops to 1/15 of what it was, and their body temperature decreases to the ambient temperature, which can be up to a 50 degree shift. (If a human drops 3.5 degrees, we become hypothermic.)
Being in a torpid state allows them to use roughly 5-30 percent of the energy they would normally use during the day at rest. This equates to saving 65-95 percent of their energy every hour!
The exceptional decrease in these functions, paired with the upside down hanging, or lulling head, might make the bird appear dead.
Waking Up
After a full night’s rest from dusk till dawn, the little guy will start to wake up. The process of getting out of torpor can take anywhere from 30 minutes to an hour. This is expected since it takes time for them to enter torpor, it will take time for them to recover.
Their heartbeat will begin to increase. As this happens and their breath begins to speed up, they start to sound like they are snoring. The only acceptable description of this is adorable!
Once their heart rate returns to normal, they will begin to vibrate. This shivering helps their bodies warm up and get back to their normal temperature. The blood begins to pump and circulate properly, and before they know it, they’re ready to dart off again and get some food.
The first meal after torpor is very important for them. They consume almost a quarter of their daily calorie intake in this first meal alone to kick start their day.
What about hummingbird Migration?‘
Hummingbirds typically migrate during the day and rest at night, but there is an exception to the rule—the Ruby-throated Hummingbird. This little guy has to travel over the Gulf of Mexico, a road trip that they are unable to take a break on.
In this case, they fly for 20ish hours. This is a situation where they are awake and flying at night. They’re able to survive this trip without perishing because they stock up on body fat (an extra 25-45% of their body weight) as energy reserves prior to the big trip!
In Conclusion
Hummingbirds are mighty little creatures! The changes their little bodies go through every day and night are evidence of how great and intricate nature is. It might seem impossible to us, these processes that we can’t imagine our own bodies going through on a daily basis, but nature is full of surprises!
Credits
Hummingbird Migration [Web log post]. (n.d.). Retrieved from https://www.worldofhummingbirds.com/migration.php
McDonald, E. (2020, July 03). Do Hummingbirds Sleep? Retrieved 2020, from https://animalhype.com/birds/do-hummingbirds-sleep/
National Park Service U.S. Department of the Interior. (n.d.). [Brochure]. Author. Retrieved 2020, from https://www.nps.gov/cham/learn/nature/upload/Hummingbirds-of-Chamizal_english.pdf
Reed, T. (2019, October 21). How Often Do Hummingbirds Sleep? Retrieved 2020, from https://birdwatchingbuzz.com/how-often-do-hummingbirds-sleep/
Shankar, A. (2018, February 23). Why I am obsessed with hummingbird pee… and torpor. Retrieved 2020, from https://blog.nationalgeographic.org/2018/02/06/why-i-am-obsessed-with-hummingbird-pee-and-torpor/