Gosh! I hope this works!
http://www.amazon.com/covers/B/00/000/3TA/B000003TA4.l.gif
They say a picture is worth a thousand words, although I must say this fella looks more like he’s drowning than swimming!
Hey, cute picture! Put a bathing suit on that kid.
Okay, here’s a reference for the chimp swimming thing: from the University of Michigan Zoology web page: “Chimps avoid water at all costs and are usually unable to swim, unless extremely excited”. It doesn’t say why, though. Or what kind of excitement they’re talking about.
If I recall correctly, Mark Mal, the current thinking is that the slightly older babies start to proccess the distance information correctly. Remember that a newborn’s brain is not fully developed at birth, and that signifigant development occurs after birth. The thinking is that the baby doesn’t percieve the cliff as being a drop quite correctly until the brain develops to the point where the connection is made from visual cues. For instance, if you put a baby on a ramp that start to increase its slant as the baby crawls along, the baby will stop crawling when it reaches a certain steepness; the angle was fairly constant if I remember the show on it correctly. I believe that Scientific American Frontiers one time did a show on it, and I remember reading about it in one of the developmental books my aunt had in her home library, though I could not state the title.
>>while contemplating the navel of the universe, I wondered, is it an innie or outie?<<
—The dragon observes
well, while many of you have given various information on the subject, no “first-hand” accounts have been given. So here goes… I am now 18. As early as 8 months (or earlier) I could swim. My mother enrolled me in a baby swim class at a local community college. This class allowed new mothers to swim with their babies. My mother says she learned how babies naturally swim from the instructor. She says I did naturally swim with no lessons (not that lessons would have done good at that age). We even have pictures of me swimming underwater. However, after that, I did not swim again for many years. Basically the “if you don’t use it you lose it” predicament happened. I forgot how to swim and had to be retaught at about the age of six. I suppose it is just instinct at birth, but since humans usually arent swimming on a daily basis, I guess they just do not use that instinct enought to hold on to it. I hope that makes sense because it is really late and I am tired. Anyway. 
ttfn.
tipi
All the archaological evidence I’ve seen suggests earliest man came down from the trees onto savannah as the process of becoming bipedal progressed, but makes no mention of aquatic varieties of human forebears. However, I believe it can be rightly argued that all life on earth had a purely aquatic environment (origin) at one some point in the distant past, and perhaps the baby swimming phenomenon might be designated as an artifact of our predecessors primeval.
So, what are we talking about here, the Australian crawl or an amoeboid pseudopod dog-paddle?
Sorry to add my comments so late, but I have been a swim instructor, mom to 2 babies, and a doc, and felt that some of the above posts needed a little clarifying.
Babies do have a breath-holding reflex. If you put their face in water, they will not inhale… for a few seconds, anyway. if you blow in their faces, they will inhale, and then they can breath-hold a few extra seconds when submerged.
When placed totally in water, they will make movements of their limbs that have slightly better than random odds of propelling them forward. If you choose to call this “swimming”, then babies can “swim”. They cannot get or keep their mouths/noses above the surface to be able to “swim” for more than 5-10 seconds at a time.
By about 6-8 months, if they have not been taught to fear water, they can hold the edge of a pool & lift their head and breathe. They can direct their motions to reach the edge of the pool from a reasonable distance. Thus if a parent holds them 8 feet from the edge of the pool & throws them halfway to the edge, the babies can make their way to the edge & get their breath. This is LEARNED, not reflexive behavior. With more coaching, a baby can learn to jump in turn around & reach the safety of the side of the pool.
There are dangers in suppressing the baby’s learned fear of water. Too many of the toddlers who drown were taught to swim, but not adequately taught to only swim with mommy(practically impossible) or adequately kept away from the water.
Watching my kids develop a love for the water has been one of the true highs in parenting. But with kids under 8 or 10, the fact that they love the water & feel at home in it requires MORE, not less, vigilence to keep them safe.
Sue from El Paso
members.aol.com/majormd/index.html
From the field…
Sorry, no 5 mo. olds in stock, but I did spend the day introducing a 23 mo. old to the ocean. We were joined in our frolics, excuse me, study, by a 17 mo. old and a 4 yr. old. The study group took to each other and spent much time in the (what do ya call it? Is it like the ski resorts?) bunny surf together. While recognizing that the sample population was not of a statistically significant size, thus saving much calculator time, it was observed: 1.) the two younger subjects exhibited no apparent innate tendency to hold their breath, 2.) the older subject did hold his breath, but previous learning experience is unknown, 3.) the two younger subjects exhibited no discernible “swimming” behaviors while the older subject attempted to kick and paddle (see qualification to 2.) above), 4.) while having experienced, during the course of the trials, some mildly unpleasant effects attributable to not holding one’s breath, neither of the two younger subjects apparently acquired knowledge from the experience that was applied in subsequent test runs, 5.) none of the subjects revealed any hesitance to repeat trials, despite aforementioned experience of unpleasant effects in the experimental environment and 6.) they dug it (high Squeal-O-Meter readings).
Regards