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Re: [AAT] Re: vernix caseosa in seal pups?

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  • Cecile MacNeille
    an interesting idea, but if birth in water were occurring in LCA would we not anticipate some sign of transient vernix caseosa in fetal great apes? regarding
    Message 1 of 6 , Mar 24, 2013
      an interesting idea, but if birth in water were occurring in LCA would we not anticipate some sign of transient vernix caseosa in fetal great apes?
      regarding gestation period: ours is the longest but not extremely different from the other apes, and ? longer gestation advantageous given the pronounced altriciality of our newborns. perhaps gestation increased stepwise with neurological complexity hence altriciality?
      gestation in days from conception
      human 266 (+- 14 days)
      chimp 230-250
      gorilla 250-260
      orang 260
      (as an aside, it is not uncommon for me to observe plentiful vernix caseosa even in babies born at 41-42 weeks, although this is certainly more likely in earlier gestations)- Cecile

       

      ________________________________
      From: aquape <m_verhaegen@...>
      To: AAT@yahoogroups.com
      Sent: Sunday, March 24, 2013 10:02 AM
      Subject: [AAT] Re: vernix caseosa in seal pups?

       
      Just found this:
      19 Weeks- "This week your baby is hitting the growth charts at 6 inches long and a full half pound in weight. Your baby's about the size of a large mango. A mango dipped in greasy cheese, actually. Vernix caseosa- a greasy white protective substance now covers your baby's sensitive skin, protecting it from the surrounding amniotic fluid. Without that protection your baby would look very wrinkled at birth. The coating sheds as delivery approaches, but some babies born early are still covered with vernix at delivery."

      If the vernix is present from the 19th week already (about halfway pregnancy) to about the 38th week, and if ontogeny is here imitating phylogeny, that would imply that our ancestors were born in the water remarkably early. Fetuses of 3 months are generally monkeylike, of 6 months, generally aquatic-ape-like (naked, upperfur later regrows in newborn chimps & gorillas): possibly the hominoid LCA or at least the great ape LCA was born in the water?? coastal or mangrove forest (salt water)?? forest swamp??

      --marc

      > Who knowns an illustration of a newborn common seal with vernix caseosa? Prof Don Bowen (Univ.Dalhousie Nova Scotia) says this "varnish" is only seen in newborn humans (esp.premature) & newborn seals (common seal pups are born in the water). --marc




      [Non-text portions of this message have been removed]
    • Marc Verhaegen
      an interesting idea, but if birth in water were occurring in LCA, would we not anticipate some sign of transient vernix caseosa in fetal great apes? Yes,
      Message 2 of 6 , Mar 25, 2013
        an interesting idea, but if birth in water were occurring in LCA, would we
        not anticipate some sign of transient vernix caseosa in fetal great apes?

        Yes, indeed, Cecile, but I don't know anything on sebaceous glands or
        squalene metabolism in the different ape spp.
        There are different possibilities AFAICS:
        - (Great) apes still have some rudiments of a vernix, but we don't know
        then (yet).
        - Their "waterborn" phase happened very long ago (eg, c 15 Ma
        peri-Tethys??), so there are +-no rudiments any more.
        - They never had such a phase (but then 19 weeks is remarkably early).

        regarding gestation period: ours is the longest but not extremely
        different from the other apes, and ? longer gestation advantageous given
        the pronounced altriciality of our newborns. perhaps gestation increased
        stepwise with neurological complexity hence altriciality?
        gestation in days from conception
        human 266 (+- 14 days)
        chimp 230-250
        gorilla 250-260
        orang 260
        (as an aside, it is not uncommon for me to observe plentiful vernix
        caseosa even in babies born at 41-42 weeks, although this is certainly
        more likely in earlier gestations)- Cecile


        Yes, I took the 38th weeks, but 39 or 40 would perhaps also not be wrong.
        In any case this suggests that until very "recently" (early sapiens
        still??) our ancestors were still strongly aquatic.

        Humans are extremely altricial on land (we only walk after 1 year, zebras
        run after less than 1 hour), but not in the water, eg, google "Meijers
        baby aquatic reflexes" or so.

        From my Nutrition & Health paper "Aquatic versus savanna":
        Slow postnatal growth
        The human species is characterised by low birth rate, single births, long
        pregnancy, rather high birth weight, very slow postnatal growth, late
        puberty & long life span, and in these respects resembles or surpasses the
        apes, the larger land herbivores & the sea mammals (Table l):
        - Single births are typical of marine mammals (incl.sea-otters, as opposed
        to freshwater otters), flying & arboreal mammals that carry their young
        (many arboreal marsupials, sloths, most bats, flying lemurs & most
        primates, even including the tiny tarsier), many ant- & termite-feeders
        (eg, aardvark) & the larger land herbivores, notably those of the
        savannas. Most carni- & omnivores, however, have multiple births. Polar
        bears have usually 2 very small young, which are hidden in dens. Examples
        of larger savanna mammals with multiple births include lions & wart hogs
        (the semi-aquatic babirusa gets only 1 or 2 small young).
        - Gestation periods longer than 9 months are only seen in mammals with
        single births, eg, the marine mammals & most larger herbivores, but not in
        arboreal mammals. In most pinnipeds it is c 11 months, but this includes a
        pre-implantation period of c 3 months. The bivalve-feeding walruses have
        gestation periods of 15-16 months, with delayed implantation of the
        fertilised egg of 4-5 months. Plankton- & fish-feeding cetaceans (with
        maternal weights ranging from 30 kg to 150 tons!) are 10-13 months
        pregnant, but squid-feeders (eg, sperm whale), 14-16 months. In seacows it
        is 12 months. Among land mammals, the longest gestation periods are seen
        in elephants (22 months), odd-toed ungulates (rhinos 8-16, tapirs 13,
        equids 11 months) & the large even-toed ones (giraffes & okapis 15, camels
        & llamas 11-13, cattle 9-11). Many of these live in open landscapes.
        - Newborn great apes weigh only 2.5-4 % of their mothers, as opposed to
        5-6 % in humans, but small primates can have higher birth weights (up to
        25 % in tarsiers). In semi-aquatic mammals the relative birth weight can
        be higher (pinnipeds, 8-10%), equal (sea-otter, 5-6 %), or lower than in
        humans (hippos, 2-3 %). As for savanna mammals, newborn aardvarks,
        elephants & rhinos weigh c 4 %, equids c 7 %, giraffes even 10-12 %.
        (Obviously, mammals with multiple births have relatively smaller
        newborns.)
        - Lactation periods of nearly 2 years are typical of the bottom-feeding
        marine mammals (beluga & narwhal, dugong, walrus - though not of
        sea-otters), and they even last longer in sperm whales, great apes, rhinos
        & elephants.
        - Female procreation starting after the age of 8 is only seen in sperm
        whales, dugongs, elephants, hippos, apes & indris (never in typical
        savanna mammals).
        - This is strongly correlated with very high longevity. Mammals with life
        spans longer than 40 years are: walruses, baleen & sperm whales, dugongs,
        elephants, hippos, most rhinos, & great apes.


        --marc

        ______

        Just found this:
        19 Weeks- "This week your baby is hitting the growth charts at 6 inches
        long and a full half pound in weight. Your baby's about the size of a
        large mango. A mango dipped in greasy cheese, actually. Vernix caseosa- a
        greasy white protective substance now covers your baby's sensitive skin,
        protecting it from the surrounding amniotic fluid. Without that protection
        your baby would look very wrinkled at birth. The coating sheds as delivery
        approaches, but some babies born early are still covered with vernix at
        delivery."

        If the vernix is present from the 19th week already (about halfway
        pregnancy) to about the 38th week, and if ontogeny is here imitating
        phylogeny, that would imply that our ancestors were born in the water
        remarkably early. Fetuses of 3 months are generally monkeylike, of 6
        months, generally aquatic-ape-like (naked, upperfur later regrows in
        newborn chimps & gorillas?): possibly the hominoid LCA or at least the
        great ape LCA was born in the water?? coastal or mangrove forest (salt
        water)?? forest swamp??

        --marc

        > Who knowns an illustration of a newborn common seal with vernix caseosa?
        >Prof Don Bowen (Univ.Dalhousie Nova Scotia) says this "varnish" is only
        >seen in newborn humans (esp.premature) & newborn seals (common seal pups
        >are born in the water). --marc
      • Cecile MacNeille
        Humans are extremely altricial on land (we only walk after 1 year, zebras run after less than 1 hour), but not in the water, eg, google Meijers baby aquatic
        Message 3 of 6 , Mar 27, 2013
          Humans are extremely altricial on land (we only walk after 1 year, zebras
          run after less than 1 hour), but not in the water, eg, google "Meijers
          baby aquatic reflexes" or so.
          <<Yes good point, and I have read Meijers work with great interest. Clearly babies have greater abilities in water than on land, but there are still aspects of development that are unrelated to locomotion:

          when comparing to the rough pattern of gestation length of other primates, humans babies when born slightly premature (in the 34-37 weeks range) generally have adequate lung maturity for survival, but with the tendency toward uncoordinated tongue action leading to poor feeding, and low fat stores and a high surface area to volume ration  making temp control problematic. and thanks for the excerpts below: very informative.      -Cecile>>

          From my Nutrition & Health paper "Aquatic versus savanna":
          Slow postnatal growth
          The human species is characterised by low birth rate, single births, long
          pregnancy, rather high birth weight, very slow postnatal growth, late
          puberty & long life span, and in these respects resembles or surpasses the
          apes, the larger land herbivores & the sea mammals (Table l):
          - Single births are typical of marine mammals (incl.sea-otters, as opposed
          to freshwater otters), flying & arboreal mammals that carry their young
          (many arboreal marsupials, sloths, most bats, flying lemurs & most
          primates, even including the tiny tarsier), many ant- & termite-feeders
          (eg, aardvark) & the larger land herbivores, notably those of the
          savannas. Most carni- & omnivores, however, have multiple births. Polar
          bears have usually 2 very small young, which are hidden in dens. Examples
          of larger savanna mammals with multiple births include lions & wart hogs
          (the semi-aquatic babirusa gets only 1 or 2 small young).
          - Gestation periods longer than 9 months are only seen in mammals with
          single births, eg, the marine mammals & most larger herbivores, but not in
          arboreal mammals. In most pinnipeds it is c 11 months, but this includes a
          pre-implantation period of c 3 months. The bivalve-feeding walruses have
          gestation periods of 15-16 months, with delayed implantation of the
          fertilised egg of 4-5 months. Plankton- & fish-feeding cetaceans (with
          maternal weights ranging from 30 kg to 150 tons!) are 10-13 months
          pregnant, but squid-feeders (eg, sperm whale), 14-16 months. In seacows it
          is 12 months. Among land mammals, the longest gestation periods are seen
          in elephants (22 months), odd-toed ungulates (rhinos 8-16, tapirs 13,
          equids 11 months) & the large even-toed ones (giraffes & okapis 15, camels
          & llamas 11-13, cattle 9-11). Many of these live in open landscapes.
          - Newborn great apes weigh only 2.5-4 % of their mothers, as opposed to
          5-6 % in humans, but small primates can have higher birth weights (up to
          25 % in tarsiers). In semi-aquatic mammals the relative birth weight can
          be higher (pinnipeds, 8-10%), equal (sea-otter, 5-6 %), or lower than in
          humans (hippos, 2-3 %). As for savanna mammals, newborn aardvarks,
          elephants & rhinos weigh c 4 %, equids c 7 %, giraffes even 10-12 %.
          (Obviously, mammals with multiple births have relatively smaller
          newborns.)
          - Lactation periods of nearly 2 years are typical of the bottom-feeding
          marine mammals (beluga & narwhal, dugong, walrus - though not of
          sea-otters), and they even last longer in sperm whales, great apes, rhinos
          & elephants.
          - Female procreation starting after the age of 8 is only seen in sperm
          whales, dugongs, elephants, hippos, apes & indris (never in typical
          savanna mammals).
          - This is strongly correlated with very high longevity. Mammals with life
          spans longer than 40 years are: walruses, baleen & sperm whales, dugongs,
          elephants, hippos, most rhinos, & great apes.

          --marc

          ______

          Just found this:
          19 Weeks- "This week your baby is hitting the growth charts at 6 inches
          long and a full half pound in weight. Your baby's about the size of a
          large mango. A mango dipped in greasy cheese, actually. Vernix caseosa- a
          greasy white protective substance now covers your baby's sensitive skin,
          protecting it from the surrounding amniotic fluid. Without that protection
          your baby would look very wrinkled at birth. The coating sheds as delivery
          approaches, but some babies born early are still covered with vernix at
          delivery."

          If the vernix is present from the 19th week already (about halfway
          pregnancy) to about the 38th week, and if ontogeny is here imitating
          phylogeny, that would imply that our ancestors were born in the water
          remarkably early. Fetuses of 3 months are generally monkeylike, of 6
          months, generally aquatic-ape-like (naked, upperfur later regrows in
          newborn chimps & gorillas?): possibly the hominoid LCA or at least the
          great ape LCA was born in the water?? coastal or mangrove forest (salt
          water)?? forest swamp??

          --marc

          > Who knowns an illustration of a newborn common seal with vernix caseosa?
          >Prof Don Bowen (Univ.Dalhousie Nova Scotia) says this "varnish" is only
          >seen in newborn humans (esp.premature) & newborn seals (common seal pups
          >are born in the water). --marc




          [Non-text portions of this message have been removed]
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