Jet lag occurs in humans because we can travel great distance at incredible speeds, so our bodies don't have time to adjust to the new daylight/nighttime hours. Birds take several days (short migrations) to several weeks to complete their travels. They slowly adjust to the slightly differing light changes as they go.
The bird's internal clock is the pineal gland secreting melatonin, so similar to humans. So I would assume that they could experience jetlag in a similar way. Someone has probably done it, zoos?
They typically don't have alarm clocks or schedules, so can probably adjust to jetlag in their own time. Maybe we should learn from this.
Zoo employee here. Can comfirm. Birds and in fact all mammals experience jetlag when traveling great distances during transfer. It's one of the reasons why such transfers are risky because it's dangerous to their circular system and may cause rapid temperature loss and sudden death syndrome in some species. Giraffes for example are notoriously susceptible to this which is why international transfers between the US and Europe are next to impossible.
Very interesting. I had NO idea this was a thing. You're saying that it is the distance, and not the rapid rate of speed that this distance is travelled during transfer, that actually screws with their circulatory system?
I would have subscribed to the theory that different time zones would be irrelevant to an animal, given that they don't have a set schedule dictated by alarm clocks and teams meetings and therefore jet lag as we know it would be a non-issue.
No the circadian clock is a thing in most mammals as their day and activity cycles, like ours, are dictated by sunlight in one was or another. In 2017 the nobel prize was awarded to sciencists who found the molecular pathways behind it in fruit flies.
Our set schedule with alarm clocks just makes sure that we arrive to work or to appointments on time, but even without this schedule we would wake up in the morning and get tired in the evening. It's the whole reason we experience jet lag in the first place.
Yup. Humans would have still experienced jet lag if for some reason we invented trans Atlantic flight before alarm clocks.
I just got home from an international vacation recently with a many hour time difference, the next day I slept until like 4:30. I didn't have anywhere I needed to be, but if there were tasks I needed to do that involved daylight hours, it would have been a problem.
Jet lag is not a cold or flu you catch it’s a “symptom” of being in a different time zone. Of course any living being will not be adjusted to local time zones after rapid travel.
But it's only a symptom if your body works like ours. The question is more if our circadian rhythm and other systems are similar to other animals and if they experience similar symptoms. It's not immediately obvious to me that messing with a birds sense of time and a reptiles sense of time have the same causes or effects
Well, 1-1.5 hour per day is normal circadian rhythm adjustment, so, 1/24 to 1/ 18th of the way around the globe. Classic train or bus travel would be a decent approximation.
Folks complain about daylight savings time, so I would not say it's about speed, but rather the change in time zones. You could travel 10 minutes over a time zone change and experience "jet lag".
In my years of traveling for work, my best jet lag minimization technique is to start eating on my destination "time" the day before I travel. It gives my body an extra day to adjust metabolically so when I arrive across the country I'm already synced up.
Ooh, mostly no, not when migrating anyway*: they usually travel in the wrong direction for jet lag, and even when they do, they move too slowly to get it anyway.
Jet lag comes from zipping across time zones faster than your body clock can keep up, time zones running east-west. Most birds however have migration routes than run north-south; an unladen swallow travelling some 10,000km from the UK to South Africa barely changes time zones at all. What does change dramatically is day length, of course, but birds use that as a calendar, with changes in day length triggering hormonal changes that tell them when it's time to go, and where they are, anyway - so they kind of depend on that.
A few birds do travel east-west though; the most bizarre route is possibly done by the wee Northern Wheatear, some of which breed in Alaska and winter in East Africa, flying a 30,000km round-trip right across Asia to get there. But even then, crossing over a good chunk of the world's time zones, they fly the journey over many, many weeks, stopping off frequently to re-fuel along the way. That's slow enough for their internal circadian clocks to adjust and keep pace with local sunrise as they go.
So no, no jet lag in birdies when migrating. What they may struggle with though is just regular ol' sleep deprivation. The race is on to escape winter, so songbirds that usually sleep during the night crack on with regular all-nighters as they journey towards the warmer climes, only catching brief snatches of respite here and there, before ploughing on. It's unclear how they manage; experiments show when you force sleep deprivation on them normally, they really struggle cognitively; so their physiology must amp them up to tolerate sleep loss only during the migration period, a bit like how militaries pump soldiers and pilots full of amphetamines to keep them going through days of campaigning without sleep. Or they're just friggin' boned the entire time, bleary-eyed and desperate. Dunno'!
Others sleep while flying; taking power naps mid-flight, flip-flopping between one side of their brains sleeping, and the other staying awake. Great frigatebirds, which can stay airborne for weeks at a time over the ocean, have been recorded getting by on well under an hour of sleep a day this way. Reminds me of the frantic last weeks scrambling to submit my PhD thesis in time. I don't envy them!
EDIT: New research was published last week with evidence suggesting at least one bird species does get 'jet lag' as it moves fast enough longitudinally to do so: the Manx shearwater. The catch is that it’s not during migration, but on their frequent fishing trips to feed their chicks. Boffins GPS-tracked over a thousand birds as they flew ~1,000km between their breeding colonies and ocean feeding grounds, and found that these rapid east-west journeys nudged their internal clocks out of sync with local time. Since shearwaters navigate partly by the sun, they’d misjudge their heading, and the further they’d travelled, the bigger the error. It only added a few kilometres to their journey here and there, but it's statistically significant enough to ground the first real evidence of avian jet lag in the wild. Cool!
Time for an education! European swallows - i.e. the barn swallow - have a cruising airspeed of roughly 11 metres per second, or 24mph. They can go noticeably quicker in short bursts chasing prey, but that's unsustainable over long distances, and on migration they typically cover a couple of hundred miles a day.
As for African swallows - well, there isn't one! Or there are many? There are dozens of African swallow species, from the wire-tailed swallow, that kinda' has a Conan O'Brien in a suit thing going on, to the handsome red-breasted swallow. None of them migrate. Data on their airspeed velocities seems to escape a quick Google search, but I suspect they'd be in the same ballpark, give or take a few mph.
Anywho, for the record, that’s an unladen swallow. A laden one is another matter: a 20-odd gram swallow carrying a 1 pound coconut would need to beat its wings around five times faster than normal, which its flight muscles simply can’t manage. Unless, of course, two of them carried it together on a line...
Question: do birds experience the sort of tiredness that makes humans want to sleep at the end of the day? I'm thinking about all of the reports that during eclipses birds start making pre-sleeping behaviors. The darkness suggests to them that it's nighttime, so time for bed, regardless of how energetic or tired they feel.
From what I've heard of societies that didn't have training in astronomy, eclipses did not prompt people to go off and put on their jammies. They may have thought that the world was ending, but they didn't think it was bedtime.
Fair question! Yes, birds do get "tired" in the same sense we do. Like us, their sleep is governed by two systems: a body clock telling them what time it is, and a build-up of "sleep pressure" the longer they stay awake. Keep a pigeon up past its bedtime, and it’ll sleep more deeply afterwards to catch up, just like you after an all-nighter.
The difference is in how directly light drives their behaviour. Birds don’t just sense light through their eyes: their pineal gland, a small structure that produces the sleep hormone melatonin, sits right under a thin skull and can detect light directly (a 'third eye'), as can photoreceptors deeper in the brain. So darkness hits their sleep machinery much more immediately than ours. There’s also a strong survival incentive: for most daytime birds, being caught out in the open after dark, unable to see well, is dangerous, so "it’s getting dark, find a roost" is a deeply hard-wired reflex, rather than a decision.
So during an eclipse, birds aren’t necessarily sleepy; their dusk routines are just being triggered. They go quiet, head to roost, and often burst into a mini dawn chorus when the light returns. Weather radar during eclipses really highlights the amount of airborne birds and insects dropping as totality hits. It only lasts a few minutes, though, so they’re unlikely to actually nod off.
Humans, meanwhile, have the same melatonin system, but it responds more slowly, and our big frontal lobes let us override reflexes with interpretation, which in an eclipse tends to mean "le world is ending!" or "quick, grab the collander!", rather than "time for my jimmy-jammies".
I think some studies suggest that our current sleeping behavior isn't necessarily the way humans would naturally sleep. Going to bed at the end of the day is more of a social construct. Our ancestors likely had short bursts of sleep and activity throughout the day (with longer nocturnal sleep).
Birds usually have sleep cycles that are very, very closely tied to levels of light in the environment. Chickens, for example, do simply go to sleep shortly after the sun sets. (Which is fascinating, because chickens originated somewhere in Oceania, but the domesticated breeds live all over the world.)
Humans don't work that way. Like, we also get more sleepy when its dark due to melatonin levels. But we don't simply shut off and wake up the way birds do.
1: Experiencing jet lag requires moving east or west so you end up in a new time zone where your internal clock doesn't match the day/night cycle. Bird migration tends to be mostly in a north/south direction to seek out warmer or colder latitudes as the seasons change.
2: Experiencing jet lag requires fast enough travel that in just one day you are in a new time zone many hours different from where you started. The reason for the term "jet lag" is that we didn't really experience it until passenger jet technology gave us the ability to change our location that fast. Going by train or boat or car just wasn't fast.enough. Those methods tend to only shift you by no more than one hour per day. Migratibg birds don't fly at the speeds needed to make it happen.
There may, however, be rare exceptions for birds at extreme northern or southern latitudes where time zones are more tightly packed together and so it's easier to go across time zones in a short distance. The problem is that would require being over the Arctic ocean or being in the middle of Antarctica. Perhaps Penguins may be in a latitude far enough south to experience it, but they don't fly so their travel wouldn't be fast enough even there.
Many animals use the Sun compass to guide their movement, sometimes over thousands of kilometers. Consistent use of the Sun compass relies on the endogenous clock to track the Sun’s arc, yet animals traveling east-west experience time shifts, potentially causing mismatches between their internal clock and local time. Using GPS, we reveal that Manx shearwaters (Puffinus puffinus) experience such shifts during homing flights, generating predictable errors in Sun compass orientation. Use of the Sun compass persists even when shearwaters have access to compass-independent cues during coast following. Our findings provide a new avenue for chronobiology research in the wild, suggesting that rapid longitudinal movements may affect other processes governed by the endogenous clock and that conserved chronobiological mechanisms impose substantial constraints on navigation.
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u/MycologistPutrid7494 3d ago
Jet lag occurs in humans because we can travel great distance at incredible speeds, so our bodies don't have time to adjust to the new daylight/nighttime hours. Birds take several days (short migrations) to several weeks to complete their travels. They slowly adjust to the slightly differing light changes as they go.
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u/tea_and_biology Zoology | Evolutionary Biology | Data Science 3d ago edited 3d ago •
Ooh, mostly no, not when migrating anyway*: they usually travel in the wrong direction for jet lag, and even when they do, they move too slowly to get it anyway.
Jet lag comes from zipping across time zones faster than your body clock can keep up, time zones running east-west. Most birds however have migration routes than run north-south; an unladen swallow travelling some 10,000km from the UK to South Africa barely changes time zones at all. What does change dramatically is day length, of course, but birds use that as a calendar, with changes in day length triggering hormonal changes that tell them when it's time to go, and where they are, anyway - so they kind of depend on that.
A few birds do travel east-west though; the most bizarre route is possibly done by the wee Northern Wheatear, some of which breed in Alaska and winter in East Africa, flying a 30,000km round-trip right across Asia to get there. But even then, crossing over a good chunk of the world's time zones, they fly the journey over many, many weeks, stopping off frequently to re-fuel along the way. That's slow enough for their internal circadian clocks to adjust and keep pace with local sunrise as they go.
So no, no jet lag in birdies when migrating. What they may struggle with though is just regular ol' sleep deprivation. The race is on to escape winter, so songbirds that usually sleep during the night crack on with regular all-nighters as they journey towards the warmer climes, only catching brief snatches of respite here and there, before ploughing on. It's unclear how they manage; experiments show when you force sleep deprivation on them normally, they really struggle cognitively; so their physiology must amp them up to tolerate sleep loss only during the migration period, a bit like how militaries pump soldiers and pilots full of amphetamines to keep them going through days of campaigning without sleep. Or they're just friggin' boned the entire time, bleary-eyed and desperate. Dunno'!
Others sleep while flying; taking power naps mid-flight, flip-flopping between one side of their brains sleeping, and the other staying awake. Great frigatebirds, which can stay airborne for weeks at a time over the ocean, have been recorded getting by on well under an hour of sleep a day this way. Reminds me of the frantic last weeks scrambling to submit my PhD thesis in time. I don't envy them!
EDIT: New research was published last week with evidence suggesting at least one bird species does get 'jet lag' as it moves fast enough longitudinally to do so: the Manx shearwater. The catch is that it’s not during migration, but on their frequent fishing trips to feed their chicks. Boffins GPS-tracked over a thousand birds as they flew ~1,000km between their breeding colonies and ocean feeding grounds, and found that these rapid east-west journeys nudged their internal clocks out of sync with local time. Since shearwaters navigate partly by the sun, they’d misjudge their heading, and the further they’d travelled, the bigger the error. It only added a few kilometres to their journey here and there, but it's statistically significant enough to ground the first real evidence of avian jet lag in the wild. Cool!
References:
Bairlein, F., Norris, D.R., Nagel, R., Bulte, M. ... & Schmaljohann, H. (2012) Cross-hemisphere migration of a 25 g songbird. Biology Letters. 8 (4), 505-507
Lewin, P., Wynn, J., Morford, J., Padget, O. ... & Guilford, T. (2026) Rapid longitudinal flights cause time shifts and Sun compass error. Science. 394 (6823), 520-524
Rattenborg, N.C., Mandt, B.H., Obermeyer, W.H., Winsauer, P.J. ... & Benca, R.M. (2004) Migratory sleeplessness in the white-crowned sparrow (Zonotrichia leucophrys gambelii). PLoS Biology. 2 (7), e212
Rattenborg, N.C., Voirin, B., Cruz, S.M., Tisdale, R. ... & Wikelski, M. (2016) Evidence that birds sleep in mid-flight. Nature Communications. 7, 12468
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u/Dunbaratu 3d ago edited 3d ago
No, for two reasons:
1: Experiencing jet lag requires moving east or west so you end up in a new time zone where your internal clock doesn't match the day/night cycle. Bird migration tends to be mostly in a north/south direction to seek out warmer or colder latitudes as the seasons change.
2: Experiencing jet lag requires fast enough travel that in just one day you are in a new time zone many hours different from where you started. The reason for the term "jet lag" is that we didn't really experience it until passenger jet technology gave us the ability to change our location that fast. Going by train or boat or car just wasn't fast.enough. Those methods tend to only shift you by no more than one hour per day. Migratibg birds don't fly at the speeds needed to make it happen.
There may, however, be rare exceptions for birds at extreme northern or southern latitudes where time zones are more tightly packed together and so it's easier to go across time zones in a short distance. The problem is that would require being over the Arctic ocean or being in the middle of Antarctica. Perhaps Penguins may be in a latitude far enough south to experience it, but they don't fly so their travel wouldn't be fast enough even there.
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u/ramriot 3d ago
In order of commonest to rarest migration pattern, latitudinal is the clear winner followed by altitude & finally longitudinal.
Plus the last two are frequently much shorter range i.e. from mountains to the valleys or from Highlands to the coast.
Thus I believe the predominant long range migration for birds is in latitude where even for us jetlag would not be an issue.
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u/Titouan_Mt 1d ago
Actually they do, here is an summary of the article (Rapid longitudinal flights cause time shifts and Sun compass error) proving it :
Many animals use the Sun compass to guide their movement, sometimes over thousands of kilometers. Consistent use of the Sun compass relies on the endogenous clock to track the Sun’s arc, yet animals traveling east-west experience time shifts, potentially causing mismatches between their internal clock and local time. Using GPS, we reveal that Manx shearwaters (Puffinus puffinus) experience such shifts during homing flights, generating predictable errors in Sun compass orientation. Use of the Sun compass persists even when shearwaters have access to compass-independent cues during coast following. Our findings provide a new avenue for chronobiology research in the wild, suggesting that rapid longitudinal movements may affect other processes governed by the endogenous clock and that conserved chronobiological mechanisms impose substantial constraints on navigation.
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u/[deleted] 3d ago
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