miércoles, 26 de octubre de 2016

Are there any social, patrilineal mammals where breeding age females are forced to leave the family group?

Another of my publications in Quora. If you don't know the site, it is a questions and answers web that once attained a good level in some topics, including ethology and animal behaviour. Then they forced some rules in order to attract more readers to the site, including an unfair unablance in favour of what they call top writers, who are obviously those who recieve more upvotes. The quality of the site went down as water in a flush and I got fed up of the site and of some gilí top writers.
Now I'm compiling my stuff here, I would say it is quality stuff.

Allow me a few words to point that this stuff is very varied and probably won't help to increase my popularity among some people such as sensible men who learn here that they could potentially suffer from endometriosis or even some gynecologists that discover that some -many- mammals also have menstruations. Probably royals can feel disturbed with this question as well, since they have a long tradition of forcing suggesting their young females to marry another royals (men).

So welcome to the gallery of surprises that is learning about animals.



Are there any social, patrilineal mammals where breeding age females are forced to leave the family group?

There are many matrilineal mammal groups from lions to orcas to chimpanzees (I think).  Are there any cases where the males stay with the family group as they mature and females that enter breeding age are forced out, or does the nature of mammalian child rearing make this highly unlikely due to the need to nurse?


 Royals and old moneys come to my mind. And stay in for good reasons. Humans in general have very ancient formula of female juvenile dispersal, and the most clear examples in western history and society are found in these types of families.

Because we are talking about sex biased juvenile dispersal.

- Apart from humans, the animal that seems to fit better in your description is painted wolf (Lycaon pyctus). And I refer to them with a bit of surprise, I used to think that they are the canine mirror of hyenas, but this is wrong when it comes to sex ratios in packsis as biased as 3 males for every female, and males consistently remain in their natal pack while females disperse.  It is very significative the fact that reproductive females are terrificly prolific, with an average of 10 puppies by litter.

- Many primates, like chimpanzees, gorillas and red colubuses. Yes, chimpanzes practise female dispersal. It is bonobos the species that opts for male dispersal. This doesn't mean that male dispersal is absent, but that female dispersal is the general rule. (Humans have been mentioned before).

- Although sex biased dispersal can be linked to social and philopatric mammals, there some other factors that can favour it, such as mortality costs of it and enviromental pressures.

Some lesser known examples, in which the sex ratio at dispersal is biased towards females: procyonidae (potus flavus), chiropetra (Saccopteryx bilineata) and Equidae (horses).

Although it is not required by your question it is interesting to tell that there can also be some type of bias in sex ratio at birth in mammals, that generally are an answer to ecological selective pressures. You can find interesting this question:
In what species of mammals males tend to outnumber females?. What could be the ecological reasons?

Interesting data in:

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