How did dogs get to be dogs? What do our four legged friends dream about? And - most importantly - are dogs really smiling at us when we think they are? All these questions (and a whole lot more)are answered by our intrepid science reporters, Jeanna and Mindy.   Below you can find links to further reading on the topics discussed in this episode.     Mystery #1: How Did Dogs Get to Be Dogs? (https://www.livescience.com/8405-dogs-dogs.html) Dogs diverged from wolves — Canis lupus — at least 20,000 and perhaps as long as 40,000 years ago A 14,700-year-old jawbone is the oldest undisputed fossil from a domesticated dog (Canis lupus familiaris)   Mystery #2: What Do Dogs Dream About? (https://www.livescience.com/53743-dog-dreams.html)   In 1977, scientists studied 6 pointer dogs, studied electrical brain activity for 24 hours: They spent 44% of time awake; 21% drowsy; 12% in REM sleep; and 23% in the deepest stage of non-REM sleep (slow-wave sleep).  For whatever reason, the size of the dog may determine the size of the dream. Smaller dogs have more frequent but shorter dream periods; large dogs have less frequent but longer dreams.  Guest editor report with Rafi Letzer: Tibetan Mastiffs Bred with Mountain Wolves to Survive at Super-High Altitudes (https://www.livescience.com/tibetan-mastiff-wolf-genes.html)     Mystery #3:  Are Dogs Really Smiling at Us? (https://www.livescience.com/65506-are-dogs-smiling.html) We have a special bond with our dogs and when  humans and dogs stare into each other's eyes, both experience a rise in levels of oxytocin Very few other animals in the world actually make eye contact with humans     Don’t forget to subscribe! You can find more answers to life’s little mysteries at the Live Science website (https://www.livescience.com/) and you can follow us on Twitter (https://twitter.com/LiveScience) and Facebook (https://www.facebook.com/livescience/) too. Tell us what your life’s little mysteries are at forums.livescience.com (https://forums.livescience.com/) .     Music by Chad Crouch - Algorithms Licensed under Creative Commons: By Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/)