how did snoring evolve?

It didn't evolve because it has a survival benefit - it evolved because people no longer die from snoring... snoring no longer attracts predators to your cave at night because we don't live in caves with predators outside.

This, combined with the fact that in many cases snoring is linked to obesity (something else that would have killed you in 'cave man' times) means that the snorers in the population are no longer being killed.

What you're asking is basically the same as asking why short-sightedness has evolved: In times gone by poor eyesight was a death sentence; now we wear contacts or spectacles.

Snoring isn't an evolutionary advantage. It's actually a mutation in the way our throats our structured more than likely. Most people who would "snore" would have gotten found by a predator. You'l also notice that older people tend to snore more than younger people. Age of the magnitude we are experiencing now (65-85) is a recent development. Nature never expected people to live past 30-40 years old, which is when most snoring develops.

Snoring has been around since we've been alive. Basically it is an alarm system that says your respiratory system is unable to function properly. When you sleep, especially for overweight people, your body's fat pressed down on your respiratory system while you sleep. While your sleeping your brain sees it as a danger and causes you to breath heavy to get more air. The extra breathing causes the snoring. Snoring is rather serious and people should get it looked at by a doctor.

Snoring is not strictly an inheritable trait so is not directly under selective pressure. Certain short snouted species of dogs or cats are well known for the tendency as a result of this snout shape trait but even a long snouted hound will snore.

Snoring is common to mammals with variation in how their airways develop in embryogenesis and heal from diseases or gradually become flaccid with age. The soft tissues vibrate when inhaling to produce the sound. Clearly this can be influenced by many factors during a life with a few genetic traits offering a likelier possibility of snoring but this a only a possible side effect from the variable combinations of what are heritable traits and the environment they grew in.

The ratio of lengths of two tandem repeats in the Runx-2 gene regulatory sequences correlate with the degree of dorsoventral nose bend (clinorhynchy) and mid-face snout length in a variety of breeds.

1- Runx-2 is a gene in dogs that is expressed in cells that lay down bone.

2- This gene has 2 variable length tandem repeats in its regulating sequences.

3 - When the repeat length is short the bone laid down in the dogs snout is different than when the repeat length is long. The short repeat length gives bull terriers long down turned, convex snouts. The long repeat length gives a shorter straight face.

These changes do not alter the gene product. The dogs all have bone. What is changed is how the gene product is regulated or how long the bone has to grow in this region.

http://www.nature.com/scitable/topicpage/Tandem-Re...

http://www.pnas.org/content/101/52/18058.full

Some combination of this gene's allele with long repeats and alleles that influence airway cartilage may predispose dogs to snore but does not guarantee snoring any more than other combinations of alleles from the relevant gene's prohibit snoring. Snoring is a medical condition but not from a direct genetic cause.

It's not an evolutionary adaptation, snoring is a symptom of many things that can be going wrong with the respiratory canal around the throat. Sometimes the cause is sleep apnoea, other times it can be cartilaginous degradation.

It's actually indicative of showing how we Homo Sapiens are not evolved fully since our bodies still can acquire defects, for example back and joint problems due to our poor bipedalism.

It may just be a by-product of evolution. Not everything that evolution gives us is beneficial. Humans are social animals, who slept together in groups in primitive times, to protect themselves from predators. So even though snoring could alert predators to their presence, it might not have made a difference as a lone predator would have a slim chance against a group of humans.

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Many animals have been observed snoring occasionally, including dogs, cats, cows, oxen, sheep, buffaloes, elephants, camels, lions, leopards, tigers, gorillas, chimpanzees, horses, mules, zebras, and elands.

I can see no evolutionary benefits and several disadvantages. Even if it is not strictly heritable there should be selection pressure against it, unless it is paired with another heritable characteristic that is beneficial.

Since it is common across a range of animals the argument that humans no longer die of it does not apply.

People snore because when they are asleep all the muscles relax and sometimes the muscles in your throat close over the airway so they vibrate when you breathe in, creating the snore.. Ummmmm??

It's not really related to evolution. It's just the fact that it hasn't really been too negative a mutation.