Register | Sign In


Understanding through Discussion


EvC Forum active members: 65 (9162 total)
5 online now:
Newest Member: popoi
Post Volume: Total: 915,815 Year: 3,072/9,624 Month: 917/1,588 Week: 100/223 Day: 11/17 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Female Infanticide?
Quetzal
Member (Idle past 5872 days)
Posts: 3228
Joined: 01-09-2002


Message 16 of 29 (59334)
10-04-2003 5:28 AM
Reply to: Message 14 by Speel-yi
10-04-2003 1:10 AM


The strategy for male rodents is to kill any young they can up until the point that they mate. Then they no longer kill.
This isn't entirely accurate. Although it appears to hold for gerbils, it is inconsistent with the literature that suggests at best males will refrain from killing their own progeny, but there is no behavioral constraint in most species against slaughtering everyone else's neonates. In fact, the communal rearing strategy used by some rodents - where the females huddle in a bunch with their pups, and in some species will even suckle the pups of their sisters (consistent with kin selection) - is a defense reaction against the males. In this case, the males apparently "recognize" the nest-scent of the pups, and will refrain from eliminating them. They don't appear constrained about eliminating the pups without this nest-scent.
By Hamiltons Rule, since relatedness is nearly equal to zero, the benefit must also be near to zero as well. On average a male rodent will benefit by this tactic to pass their genes onto the next generation. Inclusive fitness dictates that the selfish genes will work the percentages from the standpoint of relatedness. I don't think it makes any difference whether the offspring are female or not. Female hyenas will kill off their litter mates in order to dominate their cohort.
Right. Which renders any counterexample - the supposed gerbil, hamster, and mouse examples used by schraf, et al - somewhat problematic. Which is why I got on this subject in the first place. Moreover, the quite plain human "violation" of Hamilton's rule through maternal infanticide needs an explanation.
In humans, the practice of female infanticide is not uncommon, but this is mostly due to socio-economic reasons.
Again, right. However, almost any socio-economic reason for any behavior has a natural analog. I can think of few, if any, human group behaviors that don't - including religion . The analog is what I'm reaching for here. I'm actually surprised that the theists haven't jumped on this already. Aftr all, if it can be shown that maternal infanticide has no natural equivalent or adaptive explanation, then there's a tiny bit of additional weight to their argument that humans are "special" - not simply different. Admittedly a kind of gruesome argument in this case.
Genetics ultimately provides the underpinnings of behavior, although as Ehrlich describes it: "Genes do not shout commands to us about our behavior. At the very most, they whisper suggestions..." (Ehrlich, P 2000 "Human Natures: Genes, Culture and the Human Prospect", Penguin Books, New York, pg 7). Culture vs biology, again.

This message is a reply to:
 Message 14 by Speel-yi, posted 10-04-2003 1:10 AM Speel-yi has replied

Replies to this message:
 Message 17 by John, posted 10-04-2003 10:21 AM Quetzal has not replied
 Message 18 by Speel-yi, posted 10-04-2003 12:43 PM Quetzal has not replied

  
John
Inactive Member


Message 17 of 29 (59342)
10-04-2003 10:21 AM
Reply to: Message 16 by Quetzal
10-04-2003 5:28 AM


Apparently Jane Goodall reported one instance of infanticide by females.
This doesn't fit into the picture very well, but it's about chimps. All infanticide we've spoken of so far was committed by males, and this is the rule in primates and other animals. There are some exceptions, and one was documented by Jane Goodall.
A female named Passion began killing and eating several of the babies in her community. Together with her daughter Pom, over a period of many years they attacked and killed infants in their group. Usually when males kill a baby, they don't eat it, but these females seemed to be after meat; they'd chase and consume the infant. They were actually seen to eat 3, chase 3 others, and there were 8 others who disappeared under mysterious circumstances. In this period, there were almost no infants weaned successfully.
So this is kind of a question mark because it's only been these two individuals documented- and the daughter probably learned it from the mom- so maybe we can label this one pathological and say that it's not a part of normal chimp behavior.
No webpage found at provided URL: http://www-personal.umich.edu/~phyl/anthro/infant.html
------------------
No webpage found at provided URL: www.hells-handmaiden.com

This message is a reply to:
 Message 16 by Quetzal, posted 10-04-2003 5:28 AM Quetzal has not replied

  
Speel-yi
Inactive Member


Message 18 of 29 (59358)
10-04-2003 12:43 PM
Reply to: Message 16 by Quetzal
10-04-2003 5:28 AM


quote:
Again, right. However, almost any socio-economic reason for any behavior has a natural analog. I can think of few, if any, human group behaviors that don't - including religion . The analog is what I'm reaching for here. I'm actually surprised that the theists haven't jumped on this already. Aftr all, if it can be shown that maternal infanticide has no natural equivalent or adaptive explanation, then there's a tiny bit of additional weight to their argument that humans are "special" - not simply different. Admittedly a kind of gruesome argument in this case.
It would be Trivers parent/child conflict theory. This occurs because a child "shares" 100% of its genes with itself and the mother only 50%. The child wants as much of the resources from the mother as possible, while the mother seeks to limit that investment in order to have something for her other children. So a child born to a mother while she has another that is not yet weaned, is more likely to be killed or neglected by the mother. Female infanticide occurs in some societies because males provide more of the calories and thus ensure the contributions of food to their kin more than a female would. An example of this is the Ache in Paraguay.
You should consider that the strategy for an R-selected organism like a rodent will be quite a bit different from a K-selected like a human.
------------------
Bringer of fire, trickster, teacher.

This message is a reply to:
 Message 16 by Quetzal, posted 10-04-2003 5:28 AM Quetzal has not replied

  
Zhimbo
Member (Idle past 6011 days)
Posts: 571
From: New Hampshire, USA
Joined: 07-28-2001


Message 19 of 29 (59376)
10-04-2003 3:32 PM
Reply to: Message 15 by Quetzal
10-04-2003 4:56 AM


I could send you a .pdf of the article if you're getting hardcore about this. Send email to my yahoo.com address, username is zhimbo.
The behavior isn't direct infanticide, but is "active rejection" (the author's words) of pups. It's gender specific, and the article is about the adaptive nature of this for this species. Males will lose out on body weight, and are the first to die. It's a fine line between "deliberate neglect" which leads to death and "infanticide".
Apparently "brood reduction" is pretty well documented in various birds, and the McClure article lists three citations after the claim "there are few reports of litter reduction in mammals."
[This message has been edited by Zhimbo, 10-04-2003]

This message is a reply to:
 Message 15 by Quetzal, posted 10-04-2003 4:56 AM Quetzal has not replied

Replies to this message:
 Message 20 by bruchid girl, posted 07-25-2006 1:19 AM Zhimbo has not replied

  
bruchid girl
Inactive Member


Message 20 of 29 (335068)
07-25-2006 1:19 AM
Reply to: Message 19 by Zhimbo
10-04-2003 3:32 PM


This is in response to the original request of a mammalian example where a female kills her own offspring. I have myself been looking for examples of this, and have found it very difficult. I have yet to find a peer reviewed article documenting this occurance, but it is well known to occur in Norway rats http://www.ratbehavior.org/infanticide.htm, at least those kept in captivity. I have also heard of cases in Kangaroos where the mother (who is capable of superfetation) will remove one young from her pouch in order to allow a second to continue developing when resources are scarce. While not a mammalian example, I believe coots regularily kill a portion of their clutch. Hope that helps!

This message is a reply to:
 Message 19 by Zhimbo, posted 10-04-2003 3:32 PM Zhimbo has not replied

Replies to this message:
 Message 25 by Wounded King, posted 07-25-2006 2:22 PM bruchid girl has not replied

  
capeo
Inactive Member


Message 21 of 29 (335159)
07-25-2006 12:35 PM


I would think human's ignoring the general foundations of Hamilton's Law needs no direct evolutionary explanation. It would seem more likely a by-product of our brains' evolution, specifically the ability to be cognizant of future socio-economic scenarios with great detail. Some the example's already stated (China, Victorian England, India...) show cultural and socio-economic selection defeating instinctive drives of kin selection.

Replies to this message:
 Message 22 by AdminPD, posted 07-25-2006 12:53 PM capeo has replied

  
AdminPD
Inactive Administrator


Message 22 of 29 (335162)
07-25-2006 12:53 PM
Reply to: Message 21 by capeo
07-25-2006 12:35 PM


Welcome to EvC
Welcome bruchid girl and capeo,
Glad you decided to add to our diversity. We have a wide variety of forums for your debating pleasure, but I warn you it can become habit forming.
In the purple signature box below, you'll find some links that will help make your journey here pleasant.
Pay particular attention to our Forum Guidelines and all will go well.
Again welcome and happy debating. Purple

Usually, in a well-conducted debate, speakers are either emotionally uncommitted or can preserve sufficient detachment to maintain a coolly academic approach.-- Encylopedia Brittanica, on debate

Links for comments on moderation procedures and/or responding to admin msgs:
  • General discussion of moderation procedures
  • Thread Reopen Requests
  • Considerations of topic promotions from the "Proposed New Topics" forum
    Helpful links for New Members:
    Forum Guidelines, [thread=-19,-112], [thread=-17,-45], and Practice Makes Perfect

  • This message is a reply to:
     Message 21 by capeo, posted 07-25-2006 12:35 PM capeo has replied

    Replies to this message:
     Message 24 by capeo, posted 07-25-2006 1:00 PM AdminPD has not replied

      
    capeo
    Inactive Member


    Message 23 of 29 (335164)
    07-25-2006 12:57 PM


    Thinking about it I wondered if PPD had been worked into evolutionary theory and it has:
    http://www.anth.ucsb.edu/projects/human/ppd.pdf
    http://itb.biologie.hu-berlin.de/~hagen/papers/perinatal.pdf
    The gist of which is that PPD is not a pathology but an expressed response, which leads to me ask if similar theories have been put forth for other apes. This might lead to the answer of your original question, Quetzal.

      
    capeo
    Inactive Member


    Message 24 of 29 (335165)
    07-25-2006 1:00 PM
    Reply to: Message 22 by AdminPD
    07-25-2006 12:53 PM


    Re: Welcome to EvC
    Thanks,
    glad to be here.

    This message is a reply to:
     Message 22 by AdminPD, posted 07-25-2006 12:53 PM AdminPD has not replied

    Replies to this message:
     Message 26 by Quetzal, posted 07-25-2006 2:24 PM capeo has not replied

      
    Wounded King
    Member
    Posts: 4149
    From: Cincinnati, Ohio, USA
    Joined: 04-09-2003


    Message 25 of 29 (335190)
    07-25-2006 2:22 PM
    Reply to: Message 20 by bruchid girl
    07-25-2006 1:19 AM


    There was an article about this in the NY Times last mother's day. It mentions the kangaroo example as well as touching on infanticidal, not neccessarily directly, behaviour in pigs and rabbits.
    TTFN,
    WK

    This message is a reply to:
     Message 20 by bruchid girl, posted 07-25-2006 1:19 AM bruchid girl has not replied

      
    Quetzal
    Member (Idle past 5872 days)
    Posts: 3228
    Joined: 01-09-2002


    Message 26 of 29 (335192)
    07-25-2006 2:24 PM
    Reply to: Message 24 by capeo
    07-25-2006 1:00 PM


    capeo and bruchid girl
    Thanks to both of you for your replies and comments. Unfortunately, I suffer from a severe attention span deficit. The question in the OP has inevitably fallen off my personal radar screen over the past few years.
    On the other hand, welcome to EvCForum! From your quality of your replies, I very much look forward to reading your input on other topics.

    This message is a reply to:
     Message 24 by capeo, posted 07-25-2006 1:00 PM capeo has not replied

      
    macaroniandcheese 
    Suspended Member (Idle past 3927 days)
    Posts: 4258
    Joined: 05-24-2004


    Message 27 of 29 (335203)
    07-25-2006 2:55 PM
    Reply to: Message 1 by Quetzal
    10-03-2003 8:01 AM


    btw. you do know that male offspring take more resources to raise right? in humans, there is an increase in female births to women with absent husbands (business trips included). there was a story on it on npr last year. i can find it if you like.
    instances of male infanticide are easy to explain thus in times of want.

    This message is a reply to:
     Message 1 by Quetzal, posted 10-03-2003 8:01 AM Quetzal has not replied

      
    capeo
    Inactive Member


    Message 28 of 29 (335204)
    07-25-2006 3:01 PM


    LOL... I didn't realize this post started in 2003!
    Brennakimi,
    if you would like to the find the article I'd certainly read it.
    Thanks

      
    mick
    Member (Idle past 4986 days)
    Posts: 913
    Joined: 02-17-2005


    Message 29 of 29 (339919)
    08-14-2006 2:56 AM
    Reply to: Message 1 by Quetzal
    10-03-2003 8:01 AM


    resorption of the litter
    Hi Quetzal,
    You might look up resorption of litters which is reasonably common in mammals. Here's an image of a litter being resorbed by a mother mouse:
    Top left is the full litter, bottom left is the litter being resorbed at 15 days, bottom right is 18 days. The litter is genetically abnormal so (apparently) the mother recycles them.
    Mick

    This message is a reply to:
     Message 1 by Quetzal, posted 10-03-2003 8:01 AM Quetzal has not replied

      
    Newer Topic | Older Topic
    Jump to:


    Copyright 2001-2023 by EvC Forum, All Rights Reserved

    ™ Version 4.2
    Innovative software from Qwixotic © 2024