This behavior has practically nothing to do with Labradors. Many, many dogs regardless of breed can do this. Cats too. And foxes and wolves and rats and... well pretty much all quadrupeds with reasonable sizes limbs relative to their body. You might notice it's more or less the same motion as walking. Animals that drown usually do so from exhaustion, not because they can't keep their head above water.

Primates are relatively unique in their complete lack of innate swimming abilities.

Yes, while these motor reflexes are not innate, autonomic responses remain. Search for the "mammalian diving reflex".

> Primates are relatively unique in their complete lack of innate swimming abilities.

Human babies can swim, so it's maybe more initially an innate one that gets lost. Though they won't be able to keep their head over water by default if that's what you meant (can be trained to as a toddler). But I'm talking about swimming on the umbilical in water births, etc., showing that there isn't a complete lack of innate swimming abilities.

Is it "primates" or is it the strange semi/erect limb attachment that primates have?