As such, there is worry about separation. To ensure they don't drift away while they slumber, they've been known to hold hands in pairs and small groups. Sea otters also wrap themselves in a strand of seaweed growing on the ocean floor to use as a kind of anchor. When a baby sea otter — called a pup — is too young to float on its own, it sleeps on its mom's belly as she floats on her back.
Migratory birds such as the alpine swift pictured and the albatross spend much of their lives traveling or on the hunt; researchers have found that alpine swifts can stay in the air for straight days without landing.
So, when do they sleep? These birds are multitaskers that can sleep and eat while flying. Scientists believe that birds, like whales, ducks, and walruses, are unihemispheric sleepers.
They sleep while gliding and soaring — whenever they're not flapping. Meerkats live in underground burrows in groups called mobs or gangs. Housing as many as 40 meerkats , the burrows contain numerous sleeping chambers, including ones used only when breeding.
When meerkats lie down to rest, they do so in heaps, piled on top of each other for warmth. The matriarch is typically buried deepest in the group so she gets the best sleep possible. The meerkats on the outside don't reach REM sleep so they can stay alert and watch for predators. In the summer, the meerkats may spread out more and sleep above the ground. Much about how sharks sleep is unknown, but there are some things we understand.
For sharks to breathe, they must pass water over their gills. That's why most sharks sleep while moving. Smaller species of shark — such as the nurse shark — are exceptions, as they can use their spiracles small holes behind each eye that aid in breathing to force water over their gills while they lie still on the ocean floor. In , we learned more when researchers filmed a great white shark sleeping.
She faced directly into strong currents with her mouth open, likely so that water could continue to pass over her gills. Her swimming slowed, making researchers believe she was asleep, and they marked this as a sleeping behavior. The footage was shared as part of Discovery's annual Shark Week.
See it here:. We are all familiar with hibernation, which is when certain animals conserve their energy by lowering their metabolisms and "sleeping" through cold months. Some snail species hibernate, but that's not all — they also estivate. Estivation is the summer version of hibernation, in which animals enter a prolonged dormant state to protect themselves from dryness and dangerously high temperatures. Snails can estivate for years.
In , a British museum worker found the shell of an Egyptian land snail, assumed it was empty, and attached it to an identification card. Four years later, someone noticed traces of slime on the card. It was put in water, and when the shell came off the card, the live, awake snail crawled out.
It was estivating all that time. Like snails, frogs use both hibernation and estivation as sleep strategies. Frogs that estivate are found mainly in Africa and South America. During dry spells, they burrow into the soil and shed several layers of skin to form a cocoon, leaving their nose exposed to breathe.
When the rain comes again, they shed the cocoon and climb up to the surface. Some aquatic frogs hibernate underwater, resting atop or partially buried in the mud to ensure access to oxygen-rich water. Terrestrial frogs, like the wood frog and American toads, hibernate by burrowing into the soil below the frost line or hiding in cracks in logs or rocks.
But many animals hibernate and even estivate. What makes the frog so interesting is its biologically built-in antifreeze system. As ice crystals form in its body in its bladder or under its skin , a high concentration of glucose in the body keeps major organs from freezing. The heart may stop beating and the frog may stop breathing, but come spring, it will thaw and return to normal. There may not be any animal as famous as bears when it comes to hibernation, but they have a lesser-known special hibernation skill: giving birth.
A pregnant bear that settles in to hibernate will rouse herself briefly to deliver one or more cubs. They are like the fingerprints on humans, no two of them are alike. Studies have also shown that the stripes are good for deterring blood-sucking insects, such as horseflies, from attacking them. One African folk tale explains that the zebra got its black stripes after fighting with a baboon.
The zebra kicked the baboon so hard that the zebra fell over into a fire. In the Native American culture, the zebra symbolizes balance and sureness of path. Are Zebras Endangered? Are Zebras Horses? How Long Do Zebras Live? What Do Zebras Eat? Where do Zebras Live? Zebra Facts 1. Zebras sleep while in a standing position. Zebras make a range of noises, some of which are the same as horses while others are unique. Braying like this can be heard over great distances and is used to find potential mates.
Finally, zebras also have a surprisingly high-pitched bark. Zebras are very speedy animals, and can reach speeds of up to 65kph when galloping across the plains. This is just fast enough to outpace predators such as lions. Foals can run with the herd within a few hours of birth. This is because air moves at different speeds over light-absorbing black stripes and light-reflecting white stripes, so the zebra creates its own cooling air currents.
A dazzle of zebras is the most common collective noun, named for the motion dazzle effect created by a group of running zebras. While Grevy zebra society tends to be fairly open, that of plains and mountain zebras is more tight-knit, with the animals living in harems of up to six breeding females and their young, with a dominant male.
Each female has a place in the hierarchy. These groups are so close that if a predator injures one individual, fellow members will circle it and attempt to scare the intruder away with their teeth and hooves. Home Animal Facts Mammals Zebra guide: species facts, where they live and migration.
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