The complex relationship that drove Van Gogh to cut off his ear
With lifespans in the wild of over 100 years, the Galápagos giant tortoise is one of the longest-lived vertebrates. These noble creatures do occasionally yawn, but like other tortoise species, if you see one yawn or gape for too long, then an underlying health issue is the likely reason.
Canines sometimes yawn in response to their owners' yawns, the so-called contagious effect. But dogs can also yawn because they are stressed or confused.
See also: Marvel at the most radiant wildlife on Earth.
Yawning occurs in just about every vertebrate animal. And yawning in many animals, including birds, is frequently associated with drowsiness. But not exclusively.
For example, while most species of birds open their beaks in a fair impression of a mammalian yawn, no one has yet proven whether or not this "jaw stretching" also regularly includes the inhalation and exhalation of air. Some species of penguin employ yawning as part of their courtship ritual. And for other noisy and gregarious birds like parrots, yawning serves as a social signal.
With primates, yawning is a sign of sleepiness. But a yawn can also convey complex social messages, for example, to demonstrate friendliness and aggression. Furthermore, yawning can be contagious.
In humans, yawning is demonstrably contagious, as it is easily triggered by seeing, hearing, reading, or simply thinking about another individual yawning. Similarly, with primates, and especially monkeys, yawning is contagious between individuals.
Anyone who owns a pet dog will know that canines often yawn after seeing people yawn. Cats also demonstrate this kind of empathy towards their owners. Cats and dogs, however, also advertise their need for sleep, and will yawn simply because they are genuinely tired and in need of rest.
In the animal kingdom, many animals yawn, even creatures as diverse as fish and reptiles. Indeed, some snakes yawn after a good meal (in fact, it’s a way of realigning their jaws after eating). Siamese fighting fish yawn to show aggression.
A 2014 study suggested that the reason humans yawn has nothing to do with tiredness of boredom. Instead, we yawn in order to cool down our brains, thus enabling us to think more clearly. In hot temperatures, yawning increases both the heart rate and blood flow while delivering a sizable shot of air to the head, cooling the blood in that area.
But does that have the same effect on animals?
Well, science can’t agree.
Cooling the brain is one theory. Another is that when oxygen levels are low or carbon dioxide builds up in the body, an animal will yawn to recharge its lungs with a super-capacity intake of breath.
The truth is that no one really knows why some animals yawn, or appear to do so. But one thing is certain: when it's time to snooze, there are certain members of the animal kingdom that look absolutely stunning in their state of semi-slumber.
Click through this gallery for some wonderful sleepy wildlife moments.
A resident of Antarctica, these seals spend the entire year on the pack-ice zone. While agile swimmers, crabeaters can reach speeds on land of 12–16 mph (19–26 km/h) over short distances. Now that's how you earn a rest!
Feeding and drinking on the fly burns up a lot of energy. This barn swallow was observed taking a break and catching its breath after strenuously readying its lunch.
An early starter, this stocky, good-looking bird is often seen at sunrise perched prominently on trees, posts, or other suitable "lookout" points resting between dazzling displays of speed and agility as it hunts its prey. These lookouts also serve as handy rest stations.
This North American resident forages in flight or picks up snacks while swimming, walking, or wading—and all that activity can get a tad tiring on occasion.
Active mainly from dusk till dawn, this handsome big cat rests during the day in thickets, among rocks, or over tree branches.
It can be very tiring growing up as a Japanese macaque. Also known as the snow monkey, these active primates love to bathe together in hot springs and roll snowballs for fun. No wonder junior here needs some shuteye.
These guys take top billing when it comes to yawning. Its huge beak and large plump body makes the white pelican one of the longest birds native to North America, and its gape is one of the widest on the continent.
Playful and gregarious, otters can hunt for three to five hours a day—a good excuse, therefore, to recuperate all that expended energy by taking a well-deserved nap.
It's common to see this wily and intelligent creature under starlight in suburban and urban areas. But its late-night sojourns induce wide-open yawns as dawn breaks.
Mandrills often yawn, but yawning is also part of this primate's threat repertoire: it will flash its powerful canine teeth in a menacing fashion if threatened. Mandrills also yawn when they are not able to perform a desired activity.
Known as the grizzly bear across North America, these massive beasts are largely nocturnal but are often seen up and around at dawn and early evening. In bears, yawning can be a sign of stress, or it can simply mean it's sleepy. Best to not get too close to find out though.
Roaring or yawning? Incredible sleepy wildlife moments
Why do some animals yawn?
LIFESTYLE Animals
Yawning occurs in just about every vertebrate animal. And yawning in many animals, including birds, is frequently associated with drowsiness. But not exclusively.
For example, while most species of birds open their beaks in a fair impression of a mammalian yawn, no one has yet proven whether or not this "jaw stretching" also regularly includes the inhalation and exhalation of air. Some species of penguin employ yawning as part of their courtship ritual. And for other noisy and gregarious birds like parrots, yawning serves as a social signal.
With primates, yawning is a sign of sleepiness. But a yawn can also convey complex social messages, for example, to demonstrate friendliness and aggression. Furthermore, yawning can be contagious.
In humans, yawning is demonstrably contagious, as it is easily triggered by seeing, hearing, reading, or simply thinking about another individual yawning. Similarly, with primates, and especially monkeys, yawning is contagious between individuals.
Anyone who owns a pet dog will know that canines often yawn after seeing people yawn. Cats also demonstrate this kind of empathy towards their owners. Cats and dogs, however, also advertise their need for sleep, and will yawn simply because they are genuinely tired and in need of rest.
In the animal kingdom, many animals yawn, even creatures as diverse as fish and reptiles. Indeed, some snakes yawn after a good meal (in fact, it’s a way of realigning their jaws after eating). Siamese fighting fish yawn to show aggression.
A 2014 study suggested that the reason humans yawn has nothing to do with tiredness of boredom. Instead, we yawn in order to cool down our brains, thus enabling us to think more clearly. In hot temperatures, yawning increases both the heart rate and blood flow while delivering a sizable shot of air to the head, cooling the blood in that area.
But does that have the same effect on animals?
Well, science can’t agree.
Cooling the brain is one theory. Another is that when oxygen levels are low or carbon dioxide builds up in the body, an animal will yawn to recharge its lungs with a super-capacity intake of breath.
The truth is that no one really knows why some animals yawn, or appear to do so. But one thing is certain: when it's time to snooze, there are certain members of the animal kingdom that look absolutely stunning in their state of semi-slumber.
Click through this gallery for some wonderful sleepy wildlife moments.