I was going to post on an orangutan who has figured out how to whistle, but the video commentary was inane, and this video of an orangutan giving birth is really neat. I imagine some might find it kind of gross though. After all, she eats the placenta and sucks her baby's head to clean him.
I can't help but to wonder when during human evolution we stopped licking our newborn babies. I've heard some cultures still do this. This sort of grooming also reminds me of some really cool research on mice that found that this initial licking and grooming postpartum is essential for normal physiological development. It kick starts digestion and lays the foundation for how the baby's HPA-axis functions later in life.
The HPA-axis, or hypothalamic-pituitary-adrenal axis, refers to the nervous and endocrine system that regulates the physiological response to stress. Rodents that don't receive early grooming grow up to have abnormal reponses to stressors; namely they release too much cortisol under duress.
Chronically high levels of the hormone cortisol have been shown (including among humans) to be associated with a weakened immune system, depression, and brain atrophy. That's really putting into a nutshell what I learned in what may be the most freakishly awesome seminar I took during grad school: Psychoneuroimmunology, or PNI.
If you would like to learn more about how behavior, mood, hormones and the nervous system interact to affect your health I highly, HIGHLY recommend the book Why Zebras Don't Get Ulcers by Robert Sapolsky. Although he is as mega-scientist who professes at Stanford, the book is as readable as it is fascinating and entertaining. I freaking loved this book! Of course, he's also a primatologist and he has a wicked sense of humor. His other books are fantastic too, by the way. You cannot go wrong.
I still remember the day back in grad school when I was in the mail room and a fellow (newbie) grad student (who came to study PNI specifically) saw the book sitting on the counter and made some snide remark about how he hated it when laypeople jumped on the stress/immune system bandwagon and didn't know what they were talking about. It was then that I decided that he was an arrogant, ignoramus little snot. He had no clue who Robert Sapolsky was. Maybe Mr. Sapolsky shoulda put his big PHD behind his name on the book cover. In any case, I got the last laugh that day. I don't even know why I even still remember that, honestly, but it evidently made an impression.