You have heard many times that humans need around eight hours of sleep every night in order to stay healthy. However, getting enough sleep does not look the same for every species, nor is it always obvious if your pet is sleeping. If you’re worried that your pet is sleeping way too much or far too little, you should first check for how long it is supposed to sleep. The wide variety of optimal sleep times may surprise you.

Dogs and Cats

Your four-legged friends require much more sleep than you do. The average dog usually needs at least 12 hours of sleep a day, and that number goes up for puppies and aging dogs. Dogs that help humans, such as service dogs and dogs that work with police officers or military personnel, will probably sleep for longer chunks of time when they can than dogs that are only pets. Additionally, they may sleep more if they are sick or adjusting to a new living situation. Cats sleep even longer, with an average of 15 hours a day. You will probably notice that your cat is most awake in the early morning and when the sun goes down. Most of your cat’s sleep takes place during the day.

Snails

If you have just purchased a snail as a pet or if you frequently see them outside your house, you may be wondering, “How long do snails sleep?” The answer varies based on the snail’s environment. If conditions are good, snails sleep for a long time, around fourteen hours, and then stay awake for over a full day. However, if the climate is too dry for a snail to survive, it can enter a special kind of sleep in which it can stay for three years. If you have pet snails, their environment should have controlled temperatures and humidity so that they do not go into this state.

Fish

Although you may not realize it since they do not have eyelids, fish do sleep. You can tell if your pet fish are sleeping if they stick close to the bottom of their tank and do not move very much. Their fins may still move occasionally, and some large species such as types of sharks do not stop swimming at all. Pet fish may go to sleep based on when your lights are on or off, depending on if they are nocturnal or active in the day. While some fish sleep very deeply, most are ready to awaken quickly in case of a threat.

Whales

Contrary to popular opinion, whales are not fish. Like dolphins, even though they live in the water, they are mammals. Scientists are still researching these animals’ sleep behavior. However, they do know that whales sleep vertically in the water. They also continue to swim as they sleep. Whales have to think about breathing, so they sleep for very short amounts of time and then wake up. Their sleep patterns are closer to your afternoon cat naps than your full nights of sleep.

Horses

Horses, whether they are used for work or for competitions, generally need a little less than three hours of sleep per night. They get this sleep through a few naps throughout the day and some extended sleep at night. With naps, horses stay standing and generally only stay asleep for a few minutes. At night, though, they lie down and sleep. These periods of deep sleep are much shorter than humans’, though. As with other species, foals need much more sleep than grown horses, and at first, they do not take naps while standing. Older horses are more likely to doze off while standing than younger ones.

Although almost every animal needs to sleep, they all do so in different ways. So, if your new pet is sleeping much more than you think is normal, make sure you check their recommended levels before becoming worried.