Mommy's chick, daddy's...
You
can see a lot just by watching, as Yogi Berra reportedly used to say.
Some time ago we watched an interesting nature documentary about Tasmanian Devils.
This little fella sure is an interesting creature that well deserves
its name. The little devils live otherwise solitary lives, but they
occasionally gather together to dine on a carcass that is far too big
for just one devil. During such merry feeding, the devils fight with
each other, howl and act tough like some drunken teenage boys. An
interesting detail in the social life of the devil is that the male
must first win the female in a fight for her to submit to mating.
Like cats, a female devil can mate with several males sequentially and carry all their babies, although the dominant alpha male does its best to get the first and only dibs. The female can give birth to up to thirty teeny tiny young, which will then, the devil being a marsupial, have to find their way to the pouch by following a trail of slime. However, the pouch that they try to reach contains only four nipples. Therefore at most four of these young can survive, and the rest are sure to die even if they later happened to reach the pouch.
I sure can't think of another place in nature where the cold heartless cruelty of evolution is equally blatant. It is easy to see how such a cruel mechanism would have evolved when the only criterion that matters is maximizing the reproductive fitness. Those that reproduce the most outcompete those that don't. When the devil's slime trail mechanism hadn't been fully developed yet, it was profitable to produce a massive excess of young to guarantee that four of them will reach the nipples. Since at this point the young don't really cost the mother anything, wasting them is not a big loss compared to the benefit of guaranteeing that all four nipples will be productively used.
If being immoral and bad makes a species have a higher reproductive fitness, then that's what evolution will select for. Dunno, perhaps there once was a type of devil that was designed on the principle "every young is sacred" and thus produced only four young, so that each one of them could potentially reach a nipple. However, since most of these young didn't reach the nipple, the slime trail mechanism not being fully evolved yet, the reproductive fitness of such species was so much worse that after thousands of generations, it is not hard to guess whose descendants still exist and whose don't.
Of course, we can assume that the Tasmanian Devil was designed by the loving hand of the Intelligent Designer, who created it exactly the way that it is right now. (Didn't I just read somewhere that majority of Americans still believe this?) Such a design is very revealing what the values of this Designer are. As The Danimal once noted, if there is a God, it is obvious from everything that we see that He certainly does not share his values.
The documentary also feature some other species of marsupials in the same area. I found it very interesting how closely these species corresponded to our familiar "normal" animals who apparently live in the same ecological niche. I believe that this phenomenon is called either "evolutionary relay" or "convergent evolution": let some actual biologist explain it better. One of these marsupials was an obvious fox, whereas another one was an obvious rat. Despite their small size, I also thought that I saw many behavioural and physical similarities between Tasmanian Devils and bears.
Another very educational nature documentary in the same sense was the famous "March of the Penguins", that I believe just won some important award or something. The emperor penguin depicted in this documentary lives happily in the sea, but of course cannot incubate an egg there, so these penguins have to march to the dry land each year. When the penguins have finally reached their destination after the long march and chosen their mates, they pair up monogamously. The female lays a single egg that the male will then keep warm for a few months until the female comes back to feed the chick, after which the roles reverse that the female keeps the egg warm while the male walks to the sea to replenish itself.
The co-operation and effort of both mother and father are absolutely needed for the chick to survive, and in fact the male does most of the work. It follow amusingly but perfectly logically that females compete over the males, instead of the usual other way around. Since it would be evolutionarily very stupid for the male to incubate an egg of some other male penguin, the penguin females have to emphasize their monogamy at every turn. This leads to a situation where there is no evolutionary pressure at all towards sexual dimorphism that the polygamous species such as elephant seals and humans have. As far as I could tell, both male and female emperor penguins are the same size. (For a while I did wonder, though, why the males didn't evolve to be a bit larger than females since they need to live on their fat deposits during the incubation period. Perhaps the reason for this is that (a) the females also need extra energy to produce the eggs, which look pretty large and (b) being too fat would make the everyday life of penguin too difficult, since those little holes in the ice didn't look too spacious.)
One female can give birth to exactly one egg no matter what, and one male can take care of exactly one egg no matter what. When you think about it, it is obvious that the strategy of being a "cad" that is common in many other species cannot possibly infiltrate the emperor penguin population. The emperor penguin mating strategy is evolutionarily stable, to use a five-dollar term. Any individual penguin, either male or female, that tries to deviate from it will certainly fail to produce a living penguin chick.
In the emperor penguin population, it just doesn't pay off being a cad or a slut the same way it pays off in many other animal species. Of course, this is why Christians loved this movie so much, apparently not realizing that the environmental constraints that make monogamy such an effective strategy for the emperor penguins do not apply to modern humans at all. Second, the penguin monogamy lasts only for one mating season. There is no evolutionary benefit whatsoever for the emperor penguin to remain monogamous for life, and in fact, doing so would obviously be a total loser strategy.
Of course, I am sure that some people are now objecting and claiming that emperor penguin males don't have a conscious mind and thus cannot be jealous or think "I will not take good care of this egg unless I'm certain that it's mine" the way that, say, the human males would. (After all, as astonishing as this may sound, some people oppose the notion of kin selection with the argument that animals cannot possibly compute fractions in their heads.) Such thinking misses the fact that what makes some strategy good or bad is the external world that it is applied in. What the player thinks about it (or in this case, doesn't think) is totally irrelevant. The external world determines the results of following some strategy, and the subjective thoughts can have an effect only environments that allow magic.
Since us humans are conscious beings capable of reasoning, we can articulate reasons why some strategy in chess or finance or war or the mating process of emperor penguins works well. But the strategy of emperor penguin males is good or bad simply by itself even when we are not looking at it and evaluating it. If requiring monogamous behaviour from a female gives the emperor penguin male a higher reproductive fitness, then males that do so will fare better than the males that don't, even if there is not one conscious thought going on inside their little penguin heads. No conscious thinking is necessary to succeed with a strategy that we would describe using terms of conscious thought, so evolution can produce behaviours that look "intelligent" and are most concisely explained with metaphors of conscious thought but where nobody is really "home". This is truly beautiful and mind-boggling when you think about it.
A few other questions also came to me during the movie. For example, since the emperor penguin males are so close to starvation and some of them die of cold, why don't the penguins cannibalize their dead comrades and the eggs they left behind? It's not like these aren't otherwise carnivorous animals. In such dire conditions it would be strange not to use such a valuable source of protein and fat. What exactly is stopping them, some kind of Christian morals perhaps? Perhaps the penguins do eat their fallen comrades (a bit like in that episode of The Simpsons, where the penguins in the zoo flew around at night when no human was watching) but the documentary filmmakers didn't want to show this so that the movie would be more appealing to the mass audience.
Another hypothesis that I had was that that the male who is standing on the egg cannot crouch down to eat a carcass without revealing his egg to the cold. And if the penguins started eating the dead carcasses, it would soon become useful to start boosting their supply a little, eventually leading to everybody's war against everybody else. This would be disastrous for the population that has to huddle together to keep safe from the extreme cold. The emperor penguins must have evolved some internal mechanism that they used to recognize freeriders and expel them from the group.
Another issue that I had to wonder a little about was when they showed a skua bird trying to grab a penguin chick. This was almost comical with the goofy little birds hopping around, but when you think about it, obviously the skua will occasionally succeed. Heck, otherwise it wouldn't be there at all, but would have gone extinct a long time ago. Again, the filmmakers made a wise decision not to show these uglier parts of nature.
Of course, I also had a cynical hypothesis that instead of really following the penguins around for months, the camera crew just followed them for a day or two, and then with suitable editing and narration gave the impression of a longer time span. First film some penguin on the edge of the group from an angle so that no other penguins are seen in the picture and, narrate "This penguin was lost from others, so it will surely die", and so on. It's not like the audience could tell the individual penguins apart or anything, so it wouldn't matter if the very same penguin is in the next shot with his chums.
Like cats, a female devil can mate with several males sequentially and carry all their babies, although the dominant alpha male does its best to get the first and only dibs. The female can give birth to up to thirty teeny tiny young, which will then, the devil being a marsupial, have to find their way to the pouch by following a trail of slime. However, the pouch that they try to reach contains only four nipples. Therefore at most four of these young can survive, and the rest are sure to die even if they later happened to reach the pouch.
I sure can't think of another place in nature where the cold heartless cruelty of evolution is equally blatant. It is easy to see how such a cruel mechanism would have evolved when the only criterion that matters is maximizing the reproductive fitness. Those that reproduce the most outcompete those that don't. When the devil's slime trail mechanism hadn't been fully developed yet, it was profitable to produce a massive excess of young to guarantee that four of them will reach the nipples. Since at this point the young don't really cost the mother anything, wasting them is not a big loss compared to the benefit of guaranteeing that all four nipples will be productively used.
If being immoral and bad makes a species have a higher reproductive fitness, then that's what evolution will select for. Dunno, perhaps there once was a type of devil that was designed on the principle "every young is sacred" and thus produced only four young, so that each one of them could potentially reach a nipple. However, since most of these young didn't reach the nipple, the slime trail mechanism not being fully evolved yet, the reproductive fitness of such species was so much worse that after thousands of generations, it is not hard to guess whose descendants still exist and whose don't.
Of course, we can assume that the Tasmanian Devil was designed by the loving hand of the Intelligent Designer, who created it exactly the way that it is right now. (Didn't I just read somewhere that majority of Americans still believe this?) Such a design is very revealing what the values of this Designer are. As The Danimal once noted, if there is a God, it is obvious from everything that we see that He certainly does not share his values.
The documentary also feature some other species of marsupials in the same area. I found it very interesting how closely these species corresponded to our familiar "normal" animals who apparently live in the same ecological niche. I believe that this phenomenon is called either "evolutionary relay" or "convergent evolution": let some actual biologist explain it better. One of these marsupials was an obvious fox, whereas another one was an obvious rat. Despite their small size, I also thought that I saw many behavioural and physical similarities between Tasmanian Devils and bears.
Another very educational nature documentary in the same sense was the famous "March of the Penguins", that I believe just won some important award or something. The emperor penguin depicted in this documentary lives happily in the sea, but of course cannot incubate an egg there, so these penguins have to march to the dry land each year. When the penguins have finally reached their destination after the long march and chosen their mates, they pair up monogamously. The female lays a single egg that the male will then keep warm for a few months until the female comes back to feed the chick, after which the roles reverse that the female keeps the egg warm while the male walks to the sea to replenish itself.
The co-operation and effort of both mother and father are absolutely needed for the chick to survive, and in fact the male does most of the work. It follow amusingly but perfectly logically that females compete over the males, instead of the usual other way around. Since it would be evolutionarily very stupid for the male to incubate an egg of some other male penguin, the penguin females have to emphasize their monogamy at every turn. This leads to a situation where there is no evolutionary pressure at all towards sexual dimorphism that the polygamous species such as elephant seals and humans have. As far as I could tell, both male and female emperor penguins are the same size. (For a while I did wonder, though, why the males didn't evolve to be a bit larger than females since they need to live on their fat deposits during the incubation period. Perhaps the reason for this is that (a) the females also need extra energy to produce the eggs, which look pretty large and (b) being too fat would make the everyday life of penguin too difficult, since those little holes in the ice didn't look too spacious.)
One female can give birth to exactly one egg no matter what, and one male can take care of exactly one egg no matter what. When you think about it, it is obvious that the strategy of being a "cad" that is common in many other species cannot possibly infiltrate the emperor penguin population. The emperor penguin mating strategy is evolutionarily stable, to use a five-dollar term. Any individual penguin, either male or female, that tries to deviate from it will certainly fail to produce a living penguin chick.
In the emperor penguin population, it just doesn't pay off being a cad or a slut the same way it pays off in many other animal species. Of course, this is why Christians loved this movie so much, apparently not realizing that the environmental constraints that make monogamy such an effective strategy for the emperor penguins do not apply to modern humans at all. Second, the penguin monogamy lasts only for one mating season. There is no evolutionary benefit whatsoever for the emperor penguin to remain monogamous for life, and in fact, doing so would obviously be a total loser strategy.
Of course, I am sure that some people are now objecting and claiming that emperor penguin males don't have a conscious mind and thus cannot be jealous or think "I will not take good care of this egg unless I'm certain that it's mine" the way that, say, the human males would. (After all, as astonishing as this may sound, some people oppose the notion of kin selection with the argument that animals cannot possibly compute fractions in their heads.) Such thinking misses the fact that what makes some strategy good or bad is the external world that it is applied in. What the player thinks about it (or in this case, doesn't think) is totally irrelevant. The external world determines the results of following some strategy, and the subjective thoughts can have an effect only environments that allow magic.
Since us humans are conscious beings capable of reasoning, we can articulate reasons why some strategy in chess or finance or war or the mating process of emperor penguins works well. But the strategy of emperor penguin males is good or bad simply by itself even when we are not looking at it and evaluating it. If requiring monogamous behaviour from a female gives the emperor penguin male a higher reproductive fitness, then males that do so will fare better than the males that don't, even if there is not one conscious thought going on inside their little penguin heads. No conscious thinking is necessary to succeed with a strategy that we would describe using terms of conscious thought, so evolution can produce behaviours that look "intelligent" and are most concisely explained with metaphors of conscious thought but where nobody is really "home". This is truly beautiful and mind-boggling when you think about it.
A few other questions also came to me during the movie. For example, since the emperor penguin males are so close to starvation and some of them die of cold, why don't the penguins cannibalize their dead comrades and the eggs they left behind? It's not like these aren't otherwise carnivorous animals. In such dire conditions it would be strange not to use such a valuable source of protein and fat. What exactly is stopping them, some kind of Christian morals perhaps? Perhaps the penguins do eat their fallen comrades (a bit like in that episode of The Simpsons, where the penguins in the zoo flew around at night when no human was watching) but the documentary filmmakers didn't want to show this so that the movie would be more appealing to the mass audience.
Another hypothesis that I had was that that the male who is standing on the egg cannot crouch down to eat a carcass without revealing his egg to the cold. And if the penguins started eating the dead carcasses, it would soon become useful to start boosting their supply a little, eventually leading to everybody's war against everybody else. This would be disastrous for the population that has to huddle together to keep safe from the extreme cold. The emperor penguins must have evolved some internal mechanism that they used to recognize freeriders and expel them from the group.
Another issue that I had to wonder a little about was when they showed a skua bird trying to grab a penguin chick. This was almost comical with the goofy little birds hopping around, but when you think about it, obviously the skua will occasionally succeed. Heck, otherwise it wouldn't be there at all, but would have gone extinct a long time ago. Again, the filmmakers made a wise decision not to show these uglier parts of nature.
Of course, I also had a cynical hypothesis that instead of really following the penguins around for months, the camera crew just followed them for a day or two, and then with suitable editing and narration gave the impression of a longer time span. First film some penguin on the edge of the group from an angle so that no other penguins are seen in the picture and, narrate "This penguin was lost from others, so it will surely die", and so on. It's not like the audience could tell the individual penguins apart or anything, so it wouldn't matter if the very same penguin is in the next shot with his chums.
Speaking of the Tasmanian Devils, another peculiarity is that all of them who haven't died already will die shortly after reaching six years of age. There's no such thing as one with an unusually long lifespan.
Peter
Iron Rails & Iron Weights
Posted by Anonymous | 1:17 PM