Comments on: The Backward Whale http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/ A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer. Mon, 13 Feb 2012 19:00:24 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Hobgot http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-26138 Hobgot Sun, 20 Sep 2009 21:28:48 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-26138 Since the Hippopotamus gives birth underwater and head first I don't see how this find establishes one way or the other that M. inuus gave birth on land. While the suggestion that tail first birth aids the infant in finding its mother I would not say that this prevents it from drowning. Some fish, notably guppies, give birth both head and tail first alternately. Since the Hippopotamus gives birth underwater and head first I don’t see how this find establishes one way or the other that M. inuus gave birth on land.

While the suggestion that tail first birth aids the infant in finding its mother I would not say that this prevents it from drowning.

Some fish, notably guppies, give birth both head and tail first alternately.

]]> By: Brain & behaviour of dinosaurs | Medical Transcription India http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-15589 Brain & behaviour of dinosaurs | Medical Transcription India Thu, 12 Mar 2009 10:19:27 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-15589 [...] palaeontologists led by Phil Gingerich of the University of Michigan described Maiacetus inuus, a primitive whale which lived in the water but gave birth on land, and which marks the transition between modern [...] [...] palaeontologists led by Phil Gingerich of the University of Michigan described Maiacetus inuus, a primitive whale which lived in the water but gave birth on land, and which marks the transition between modern [...]

]]> By: abfabbum http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-15490 abfabbum Fri, 06 Mar 2009 05:23:16 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-15490 Turdus, can you not see the other side of this? Perhaps if the head first birth is not because of breathing then it's due to other factors, like being eaten shortly after birth if it didn't follow it's mommy. I believe that's been mentioned. This evolution has to be the result of something. Else, why would the change have occurred at all? Way to go Gingerich for finding out more about the backwards evolution of the whale from land to sea. Fascinating. Turdus, can you not see the other side of this? Perhaps if the head first birth is not because of breathing then it’s due to other factors, like being eaten shortly after birth if it didn’t follow it’s mommy. I believe that’s been mentioned. This evolution has to be the result of something. Else, why would the change have occurred at all? Way to go Gingerich for finding out more about the backwards evolution of the whale from land to sea. Fascinating.

]]> By: LOTD for February 22 « Link Collection http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14968 LOTD for February 22 « Link Collection Mon, 23 Feb 2009 07:25:48 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14968 [...] Pretty amazing that this prehistoric whale apparently lived in the water but gave birth on land: http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/ [...] [...] Pretty amazing that this prehistoric whale apparently lived in the water but gave birth on land: http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/ [...]

]]> By: Offgrid-Living.com http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14618 Offgrid-Living.com Wed, 11 Feb 2009 16:20:15 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14618 Excellent article. I'm sure we will find all sorts of dicoveries like this that will continue to amaze and astound us. Thanks for posting this information. Excellent article. I’m sure we will find all sorts of dicoveries like this that will continue to amaze and astound us. Thanks for posting this information.

]]> By: DDeden http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14608 DDeden Wed, 11 Feb 2009 05:54:20 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14608 I've read that whales give birth tail first, because the calf is born with the head facing the same direction as the mother and instinctively follows her "jetstream drag" (I don't know the right word) like a remora. If the calf was born head first, it would be facing the wrong direction and they could get separated. Sounds funny, but consider ocean currents and predators attracted to the blood, the calf sticking very close to the mother has a definite advantage. I'd guess Maiacetus gave birth in the warm lagoon shallows, like human ancestors living along tropical shores once did as well, "water babies" hold their breath until they reach the surface, of course. I’ve read that whales give birth tail first, because the calf is born with the head facing the same direction as the mother and instinctively follows her “jetstream drag” (I don’t know the right word) like a remora. If the calf was born head first, it would be facing the wrong direction and they could get separated. Sounds funny, but consider ocean currents and predators attracted to the blood, the calf sticking very close to the mother has a definite advantage. I’d guess Maiacetus gave birth in the warm lagoon shallows, like human ancestors living along tropical shores once did as well, “water babies” hold their breath until they reach the surface, of course.

]]> By: Why Evolution Is True by Jerry Coyne - Science Forums http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14579 Why Evolution Is True by Jerry Coyne - Science Forums Mon, 09 Feb 2009 16:55:26 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14579 [...] biology textbooks(although, it came out just a bit too early to contain the recently described Maiacetus innus). The end notes are a trove of excellent web-links and youtube links, many of which now rest [...] [...] biology textbooks(although, it came out just a bit too early to contain the recently described Maiacetus innus). The end notes are a trove of excellent web-links and youtube links, many of which now rest [...]

]]> By: Ancient whales greeted the world head first | FNQhome.com http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14566 Ancient whales greeted the world head first | FNQhome.com Sun, 08 Feb 2009 05:23:09 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14566 [...] et al discussing the discovery of a fossil pregnant archaeocete. Discussion can also be found at Carl Zimmer’s Loom and Greg Laden’s [...] [...] et al discussing the discovery of a fossil pregnant archaeocete. Discussion can also be found at Carl Zimmer’s Loom and Greg Laden’s [...]

]]> By: Turdus http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14546 Turdus Fri, 06 Feb 2009 02:06:27 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14546 The breathing theory makes no sense. Please explain to me how an emerging fetus can take a breath while it is in the birth canal? If the head has emerged, the fetus is unable to breathe because its chest is still in the birth canal. Mammals breathe by expanding the volume of the pleural cavity through the actions of the diaphragm and intercostal muscles, creating negative pressure in the pleural cavity. This would be impossible while the fetuses chest is still in the birth canal, especially with the muscular contractions of labor pressing on it. Once the chest has been delivered and can expand, the rest of the fetus slips out rapidly (this even applies to quadrupeds born on land, and they have a pelvis that still needs to be delivered - for animals with a cetacean anatomy it would be even easier to deliver the posterior end of the animal once the head and chest are delivered), allowing the newborn to swim to the surface and breathe. It does not matter if the tail is presented first or the head is presented first, it is impossible for the newborn to breathe during the birth process, and it does not breathe until it breaks the surface of the water. To me the idea of the calf being in danger because it might breathe during labor is silly and unproven, and I don't know why it would be accepted as orthodoxy in scientific circles. It may be one explanation but certainly not the best! OF COURSE, there must be some selective pressure on cetaceans to be born tail first, but this may be due to their specialized, non quadrupedal anatomy and the mechanics of pushing out a fetus with the cetacean shape, NOT due to the fact that they are born in water. for example, it may be that it is easier to give birth to a fetus tail first if it has a large head relative to the rest of its body and a short stiff, relatively immobile neck and no pelvis. These features are not shared by seals and other marine mammals that give birth on land. Imagine if you had push a whale or dolphin against some resistant force, but could only do it by pushing its head or its much more narrow, flexible tail. Which would you pick? Maiacetus is a quadruped, just like seals, dogs and sea otters (and I am willing to bet that the quadripedal sea otters are born head first at sea - but I don't know this for sure). Maiacetus probably gave birth like a quadruped, maybe in the water or maybe on land. It might not need to give birth tail first because its fetus did not have that specialized cetacean anatomy. I think this is a much more convincing argument than can be made for the often repeated (but unproven and unlikely) popular idea that whales are born tail first so they won't breathe prematurely during birth. Maiacetus may have given birth head first because it was still a quadruped, regardless of whether it gave birth on land or at sea. The breathing theory makes no sense. Please explain to me how an emerging fetus can take a breath while it is in the birth canal? If the head has emerged, the fetus is unable to breathe because its chest is still in the birth canal. Mammals breathe by expanding the volume of the pleural cavity through the actions of the diaphragm and intercostal muscles, creating negative pressure in the pleural cavity. This would be impossible while the fetuses chest is still in the birth canal, especially with the muscular contractions of labor pressing on it. Once the chest has been delivered and can expand, the rest of the fetus slips out rapidly (this even applies to quadrupeds born on land, and they have a pelvis that still needs to be delivered – for animals with a cetacean anatomy it would be even easier to deliver the posterior end of the animal once the head and chest are delivered), allowing the newborn to swim to the surface and breathe. It does not matter if the tail is presented first or the head is presented first, it is impossible for the newborn to breathe during the birth process, and it does not breathe until it breaks the surface of the water. To me the idea of the calf being in danger because it might breathe during labor is silly and unproven, and I don’t know why it would be accepted as orthodoxy in scientific circles. It may be one explanation but certainly not the best!
OF COURSE, there must be some selective pressure on cetaceans to be born tail first, but this may be due to their specialized, non quadrupedal anatomy and the mechanics of pushing out a fetus with the cetacean shape, NOT due to the fact that they are born in water. for example, it may be that it is easier to give birth to a fetus tail first if it has a large head relative to the rest of its body and a short stiff, relatively immobile neck and no pelvis. These features are not shared by seals and other marine mammals that give birth on land. Imagine if you had push a whale or dolphin against some resistant force, but could only do it by pushing its head or its much more narrow, flexible tail. Which would you pick? Maiacetus is a quadruped, just like seals, dogs and sea otters (and I am willing to bet that the quadripedal sea otters are born head first at sea – but I don’t know this for sure). Maiacetus probably gave birth like a quadruped, maybe in the water or maybe on land. It might not need to give birth tail first because its fetus did not have that specialized cetacean anatomy. I think this is a much more convincing argument than can be made for the often repeated (but unproven and unlikely) popular idea that whales are born tail first so they won’t breathe prematurely during birth. Maiacetus may have given birth head first because it was still a quadruped, regardless of whether it gave birth on land or at sea.

]]> By: Lurker #753 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14542 Lurker #753 Fri, 06 Feb 2009 00:43:12 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14542 @Brian Schmidt I believe otter pups are born... upwards - i.e. mother on her back. Even if they managed to fall overboard on emergence, they're already furred and >1kg in weight, and the mother would rapidly scoop them back up, so I doubt orientation is critical. @Brian Schmidt
I believe otter pups are born… upwards – i.e. mother on her back. Even if they managed to fall overboard on emergence, they’re already furred and >1kg in weight, and the mother would rapidly scoop them back up, so I doubt orientation is critical.

]]> By: Robert Rushing http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14539 Robert Rushing Thu, 05 Feb 2009 20:22:47 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14539 Just a fluke. Heh heh. Just a fluke. Heh heh.

]]> By: Whales in PLoS and Antarctica » Eclectic Echoes http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14524 Whales in PLoS and Antarctica » Eclectic Echoes Thu, 05 Feb 2009 05:34:41 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14524 [...] more about this awesome find at: Not Exactly Rocket Science, The Loom, Laelaps and A Blog Around The Clock. This is such a wonderful discovery that each of the [...] [...] more about this awesome find at: Not Exactly Rocket Science, The Loom, Laelaps and A Blog Around The Clock. This is such a wonderful discovery that each of the [...]

]]> By: Turdus http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14522 Turdus Thu, 05 Feb 2009 04:13:20 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14522 I posted this on pharnygula and will also post it here. I am in no way convinced that being born head first implies that the animal gave birth on land. There is no reason to automatically assume that being born head first would result in drowning. The fact that modern cetaceans are born head first to prevent drowning is an unproven assumption. I seem to remember seeing a film of a captive whale (sorry, can't remeber which species)being born head first and it did just fine. Maybe being born head first has something to do with the shape of modern cetaceans and uterine contractions (easier to push against a firm rounded large head than a thin soft set of flukes at the end of a narrow soft tail than it does with taking the first breath). Either way, the calf doesn't breathe until it reaches the surface and does not need to breath as long as the umbilical chord is not compressed and/or the placenta is still attached. All that is needed is a behavioral mechanism to prevent inspiration until the surface of the water is broken. Either way the fetus's head is bathed in fluid until it reaches the surface. Furthermore, who knows how close this animal was to parturition? Mammalian fetuses often change their orientation in utero prior to birth. For many mammals, either an anterior or posterior position at birth can be normal, and it is not that critical. I am in no way convinced that the fetal head position in this species proves it gave birth on land and am quite frankly surprised this is being accepted so readily by so many who should otherwise know better. Just my two cents as a Veterinarian who does a lot of reproductive work and seen a lot of dystocias. If someone can point me to some solid evidence offering proof that an anterior presentation of cetacean calves results in drowning death due to inappropriate inspiration while still submerged I will happily admit that I am wrong! I posted this on pharnygula and will also post it here. I am in no way convinced that being born head first implies that the animal gave birth on land. There is no reason to automatically assume that being born head first would result in drowning. The fact that modern cetaceans are born head first to prevent drowning is an unproven assumption. I seem to remember seeing a film of a captive whale (sorry, can’t remeber which species)being born head first and it did just fine. Maybe being born head first has something to do with the shape of modern cetaceans and uterine contractions (easier to push against a firm rounded large head than a thin soft set of flukes at the end of a narrow soft tail than it does with taking the first breath). Either way, the calf doesn’t breathe until it reaches the surface and does not need to breath as long as the umbilical chord is not compressed and/or the placenta is still attached. All that is needed is a behavioral mechanism to prevent inspiration until the surface of the water is broken. Either way the fetus’s head is bathed in fluid until it reaches the surface. Furthermore, who knows how close this animal was to parturition? Mammalian fetuses often change their orientation in utero prior to birth. For many mammals, either an anterior or posterior position at birth can be normal, and it is not that critical. I am in no way convinced that the fetal head position in this species proves it gave birth on land and am quite frankly surprised this is being accepted so readily by so many who should otherwise know better. Just my two cents as a Veterinarian who does a lot of reproductive work and seen a lot of dystocias. If someone can point me to some solid evidence offering proof that an anterior presentation of cetacean calves results in drowning death due to inappropriate inspiration while still submerged I will happily admit that I am wrong!

]]> By: Hairy Museum of Natural History » Maiacetus innus http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14520 Hairy Museum of Natural History » Maiacetus innus Thu, 05 Feb 2009 02:49:47 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14520 [...] The Loom: The Backward Whale [...] [...] The Loom: The Backward Whale [...]

]]> By: Malcolm J. Brenner http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14519 Malcolm J. Brenner Thu, 05 Feb 2009 02:36:35 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14519 Modern whales are very embarrassed by this discovery, because they believe that giving birth on land is for sissies... rather the way Navy pilots feel about the Air Force. Modern whales are very embarrassed by this discovery, because they believe that giving birth on land is for sissies… rather the way Navy pilots feel about the Air Force.

]]> By: More Transitional Whales | www.jeffthefish.com http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14512 More Transitional Whales | www.jeffthefish.com Wed, 04 Feb 2009 23:05:04 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14512 [...] Here’s a little more detail. Stumble [...] [...] Here’s a little more detail. Stumble [...]

]]> By: Brian Schmidt http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14511 Brian Schmidt Wed, 04 Feb 2009 22:27:13 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14511 Randy- the snout and teeth give it away. What taxonomists really care about though are innocuous clues like certain bones in the ear or jaw that are only found in related animals. See the wiki write-up for Pakicetus: http://en.wikipedia.org/wiki/Pakicetus (Or read Carl's book) Randy- the snout and teeth give it away. What taxonomists really care about though are innocuous clues like certain bones in the ear or jaw that are only found in related animals. See the wiki write-up for Pakicetus:

http://en.wikipedia.org/wiki/Pakicetus

(Or read Carl’s book)

]]> By: Jason http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14510 Jason Wed, 04 Feb 2009 21:53:34 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14510 Carl, You're going to have to rewrite Water's Edge just to reflect all of the recent discoveries. Carl,
You’re going to have to rewrite Water’s Edge just to reflect all of the recent discoveries.

]]> By: Randy Hill http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14509 Randy Hill Wed, 04 Feb 2009 21:51:05 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14509 I hope this is not too dumb of a question to ask on this blog, but what makes the discoverers of this fossil so sure that it is a whale (especially with the physical characteristics described in the drawing)? What makes a whale a whale? What about this fossil places it so easily into the whale "family?" I hope this is not too dumb of a question to ask on this blog, but what makes the discoverers of this fossil so sure that it is a whale (especially with the physical characteristics described in the drawing)? What makes a whale a whale? What about this fossil places it so easily into the whale “family?”

]]> By: Bjørn Østman http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14507 Bjørn Østman Wed, 04 Feb 2009 19:46:36 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14507 As far as I have understood, mammals born head first don't breathe before the umbilical cord snaps. At what point during birth does that happen in whales? I mean, there isn't much air to breathe inside the mother either, or...? As far as I have understood, mammals born head first don’t breathe before the umbilical cord snaps. At what point during birth does that happen in whales? I mean, there isn’t much air to breathe inside the mother either, or…?

]]> By: Brian Schmidt http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14506 Brian Schmidt Wed, 04 Feb 2009 19:40:00 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14506 Wiki says sea otters "usually" give birth in the sea, but no info on how the sea otter fetus presents. Any sea otter ob-gyns on this thread? I was trying to think of species that might demonstrate the transition to birth in the sea and whether breech birth precedes or follows the transition. Wild speculation would be welcome too. Wiki says sea otters “usually” give birth in the sea, but no info on how the sea otter fetus presents. Any sea otter ob-gyns on this thread? I was trying to think of species that might demonstrate the transition to birth in the sea and whether breech birth precedes or follows the transition. Wild speculation would be welcome too.

]]> By: OOKEE.com » Blog Archive » Evolving Things http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14505 OOKEE.com » Blog Archive » Evolving Things Wed, 04 Feb 2009 18:41:25 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14505 [...] of all, a new transitional whale fossil* has been discovered, filling in yet another detail of the lineage from land to sea that whales [...] [...] of all, a new transitional whale fossil* has been discovered, filling in yet another detail of the lineage from land to sea that whales [...]

]]> By: Florida Citizens for Science » Blog Archive » The Backward Whale http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14504 Florida Citizens for Science » Blog Archive » The Backward Whale Wed, 04 Feb 2009 17:28:50 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14504 [...] Read the whole story at The LOOM [...] [...] Read the whole story at The LOOM [...]

]]> By: Charles Wade http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14502 Charles Wade Wed, 04 Feb 2009 15:13:02 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14502 I am a HS physics teacher, and I was amazed by this reporting. Thank you for the good service you provide to me who loves knowledge. I am a HS physics teacher, and I was amazed by this reporting. Thank you for the good service you provide to me who loves knowledge.

]]> By: Jumblepudding http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/comment-page-1/#comment-14501 Jumblepudding Wed, 04 Feb 2009 15:02:28 +0000 http://blogs.discovermagazine.com/loom/2009/02/03/the-backward-whale/#comment-14501 Of all evolutionary conundrums, whales and bats always blow my mind the most. The thing that sorted it out for me was a comparison of their early ancestors to present-day Mouse Deer, tiny deer that hide underwater when threatened. The fact that the ancestral whales' ear canals were, through a fluke of Evolutionary developement, already "pre-made" for hearing underwater helped me get my head around it as well. Of all evolutionary conundrums, whales and bats always blow my mind the most. The thing that sorted it out for me was a comparison of their early ancestors to present-day Mouse Deer, tiny deer that hide underwater when threatened. The fact that the ancestral whales’ ear canals were, through a fluke of Evolutionary developement, already “pre-made” for hearing underwater helped me get my head around it as well.

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