If you own a pet such as a dog, you probably feel like the furry creature is part of your family. Chances are you talk to them, cuddle them, give them treats, and maybe even allow them to sleep in the bed with you at night (provided they don't take up the whole bed).

We, humans, are quite attached to our pets and willing to do just about anything for them. And they feel the same way about us.

People and animals have quite a few connections and things in common. There are just enough similarities between animals and humans to make studying animals fruitful.

Scientists have long researched animals to help them understand more about human disease, behavior, the brain, and more. Animal sleep habits are one area that is of interest to researchers and others. It sheds some light on how humans are affected by sleep or a lack thereof.

Do animals sleep like humans? What can we learn from animals and their sleep habits?

REM sleep is a common link between humans and mammals

Rest consists of cycling between non-REM and REM phases continually. Researches say that both humans and mammals go through the stage of sleep called REM sleep. REM stands for Rapid Eye Movement and is a period of rest typified by intense dreams, an elevated heart rate, and even slight twitching or movement.

During this phase of sleep, the brain sends signals to the region of the brain that is responsible for learning, hence, why we've often heard that people who don't get enough sleep cannot perform as well at work or school.

Since mammals also go through the REM phase of sleep, does this mean they dream? Scientists aren't sure on this one. They say that the best determiner of whether someone (or some animal) dreams is to ask them, and since your pet isn't likely to answer you, they can't say with complete certainty. However, there is a strong likelihood they do because they go through REM sleep.

So the next time you see your dog waving his paw around in the middle of sleeping, he just may be dreaming about wrestling a cat.

Both humans and animals need "plenty" of sleep

Chances are you probably get irritable without enough sleep. If you're not sure, ask your loved ones what you're like when you haven't had your rest.

The old saying we've always heard is that we need our eight hours of sleep. That's mostly true. Younger children need more sleep. Older adults can get by on seven hours, but eight hours of sleep is a healthy average that works for most people. When we don't get that restorative rest, it's easy to get out of sorts.

The same goes for our animal friends. When they don't get enough sleep, they can become tired, grumpy, and "harder to wake up when they do get to sleep."

So, how much sleep do animals need? Do they need eight hours too? Well, not exactly.

According to the experts, sleep requirements for an animal varies based on its size. The size of the animal correlates to their brain metabolism in most cases. What does this mean? It means that larger animals have slower brain metabolism, so they generally need less sleep. The smaller the animal, the more rest they require.

But that's not the end of the story on animals and their sleep requirements. Did you realize that horses stand 98 percent of the time? This behavior interferes with their REM sleep cycle.

We can't sleep if we don't feel safe

Have you ever slept somewhere that you didn't feel altogether safe? Maybe you didn’t feel comfortable while traveling alone. Possibly you went camping with the kids and thought you heard some creepy noises after everyone else fell asleep.

Those experiences make it difficult to get into a deep sleep when you are on edge and don't feel safe. But it's more than having a hard time getting to sleep. One part of our brain is capable of staying somewhat alert so that we can protect ourselves from danger.

Prey animals instinctively know that they should not go into a deep sleep for a very long and so they make sure this doesn't happen. Birds will sometimes sleep with only one eye closed. Birds also shut down one side of their brain for sleep while allowing the other side of their mind to keep functioning.

Researchers recently discovered an even more fantastic discovery about birds: They can shut down both hemispheres of their brain and continue flying! Their mind briefly enters the REM phase for just a few seconds at a time for safety.

Animals and people like to sleep more in the winter

We know that several species of animals hibernate for the winter. The body temperature decreases, the heart rate lowers, and the breathing slows. The entire metabolic rate reduces to a deep sleep that lasts for several months. The animal wakes up from its long snooze in the springtime.

Humans tend to sleep more in the winter too. Some people think it's the cold weather in many parts of the country that contributes to the desire to relax more in the winter. Who doesn't like to snuggle under the cozy blankets a bit longer when it's snowy outside?

The days are shorter and the nights are longer, making our nighttime routines much more enticing. Then when the first hint of spring arrives, people begin waking up to the fresh new season. Just like those hibernating animals that come out from a long slumber, we go out in the spring and start making our gardens, doing yard work, and generally soaking up more vitamin D.