Re: Diving reflex, part 2

H. M. Hubey (
27 Sep 1995 14:34:00 -0400

maarten fornerod <> writes:

>laryngeal area, and the trigeminal diving reflex (TDR), the true diving
>response, that is elicited by stimulation of the face. Placing an
>ice-cold towel against the lamb's snout resulted in a mean drop in
>heart-rate of 24%.

>Question is: how wide-spread is this terrestial diving reflex (maybe
>better: anti-drowning reflex), and does it occur in our closest relatives?
>Anyway, it doesn't seem that the diving reflex argument is a particularly
>strong one :(

I remember reading about Soviet studies in human females giving
birth in warm water. If I recall correctly the baby doesn't drown
just because he's left the womb. I remember seeing photos of
babies floating around the water (on the surface and in the water)
still attached to umbilical cords.

Maybe this whole thing has to do with holding the breath while
in the womb, and not with diving. That could be the reason for
greater change in newborn animals than older ones. But then the water
temperature should not make a difference.

But then the diving reflex could simply be a further strengthening
of an already existent capability. In a sense all mammals seem to
be aquatic (before birth anyway :-)).


Regards, Mark