Megatron

Ok, here's a question Baloo and I ran into <a href="http://iidb.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=50&t=000374" target="_blank">here in EoG</a>...

Are there any other animals that are known to have more parental dependency than the human being?

If so, how?

scigirl

Well, more is an interesting term.

Many mammals require their mother for a source of food, and some sort of "upbringing" or they die. How can you need more upbringing than already needing it to survive? It's like asking whether you can need oxygen more than we do?

Although maybe I should actually read the thread you linked to, and the question will become more clear to me.

Ok here is Baloo's post from that thread:
Well again it's an interesting question. On the one hand, we definitely need parents for food, shelter, and such. No question, a baby left on the street would die, as would many mammalian babies.

But since we learn to reason at an early age, perhaps we outgrow the physical need for parents earlier than some mammals (relatively speaking). But culturally we still need them (can't even work till you are 16 in this country). Does that make any sense?

scigirl

[ June 13, 2002: Message edited by: scigirl ]</p>

lpetrich

The long childhood in our species may be a way of taking a long time to do a large amount of learning. For example, (natural) languages are most easily learned in childhood, the ability decreasing after puberty. Having several years to learn makes it possible to learn a large amount of vocabulary and grammar.

And more than that, mental development continues through childhood. An interesting example is that one acquires a conscience in mid to late childhood. Some people never acquire that, and manifest "antisocial personality disorder", displaying

Failure to conform to social norms
Deceitfulness
Impulsivity
Irritability and aggressiveness
Reckless disregard for safety of self or others
Consistent irresponsibility
Lack of remorse

Such people often become criminals, but some people may discover "legitimate" niches in society in which one can get away with sleazy behavior. But such people can also be very charming.

All of this is much like earlier-childhood behavior; children will shamelessly lie about misbehavior, but can also be very charming.

Development of a conscience is connected with development of a part of the brain, the prefrontal cortex; those with antisocial personality disorder may have an inadequately-developed prefrontal cortex. I wonder if it might be possible to deduce prefrontal-cortex size from skull shape; it might be interesting to work out how it had evolved.

Looking elsewhere, dependence on parents is common among birds; when they hatch, they often must be fed by their parents for a few weeks or months.

However, outside of mammals and birds, such parental dependence is very rare. However, honeybees do come close with their queens being unable to survive without the assistance of worker bees. Queens never have most of the skills of workers, and when a queen leaves a hive to found a new one, she takes along a big swarm of workers.

By comparison, in most other social-insect species, colonies are founded only by the reproducers, who perform some of the workers' tasks until enough workers mature.

lpetrich

Phenomena like parental dependence and worker dependence may seem like good examples of "irreducible complexity", but there are several examples of intermediate states.

Choosing a spot to lay eggs
Sitting on the eggs
Finding food for the hatchlings
Secreting milk for them
Continuing to do so after switching to giving birth (sitting on eggs replaced by pregnancy)

Honeybee evolution could have gone like this:

• Solitary bees: females look for good places to nest; they lay their eggs and feed their larvae at such places
• Some places cramped: a female's daughters might find it hard to find a new home, and might sometimes prefer to stay with their mother and raise their brothers and sisters.
• Bumblebee-like: the mother could keep her daughters from reproducing, thus making them sterile workers. However this queen still has to found a hive without assistance.
• Swarming starts: a queen may recruit workers to help in founding a new hive. This makes it easier to start new hives.
• Unassisted hive-founding atrophies.
• Honeybee: queens are always dependent on workers, and they need to recruit swarms of them to found new hives.

[ June 13, 2002: Message edited by: lpetrich ]</p>

KeithHarwood

I was under the impression that it was the other way round; that we have a physical need for parents relatively much longer than for other mammals. We are born prematurely to get that bloody great head out, need much more development outside the womb and afterwards need much more training to become a functioning member of the species.

scigirl

Could be, Keith.

All I know is, we could probably grow up a lot sooner than we do, if society allowed it. Age 21 to be an adult??? We could be functionally "adults" much much earlier (biologically speaking).

scigirl

Baloo

Ok, just disconvered this thread, so bear with me. First, a disclaimer: this is intended as more of a "mental masturbation" topic than anything else - it really has no bearing on the original theory posted to EoG thread (that is: in the "Need for God" thread, I postulated that the dependence on God may stem from a cultural development in which the young within a culture, rather than being allowed to shed, with age, the innate, instinctual drive to trust, love, and obey parental figures were actually conditioned to transfer that drive towards the non-existent deity believed to control the fortune and fate of the culture of their uprising). In other words, imagine that we're a bunch of directionless college students sitting in a lounge, with nothing better to do with our time than have a lively discussion about a topic utterly and completely inane and non-applicable to our lives on this planet.

Anyway, the sidebar question, in nutshell, is whether homo sapiens "lead" the animal kingdom in the "dependency of offspring on parents". In order to resolve this utterly useless question, we need an objective measure of offspring dependency.

May I suggest defining an offspring dependency ratio (ODR) calculated as

ODR = (Average timespan for a species between birth and ability to surive independent of parental aid) / (Average timespan between birth and death)

In the US, for instance, we'd probably see an average ODR something like (18 years)/(75 years), or ODR=.24. For dogs, however, the ODR is more along the lines of (2 years)/(12 years), or ODR = .17. If we look at the pre-historic homo sapiens as the base ODR for our species, I imagine the ODR would be significantly greater - on the order of (15 years)/(30 years), or ODR = .5.

Question 1: If this definition of offspring dependency is accepted, do any of the biology experts in this thread know of any species which would have ODR's matching or exceeding that for homo sapiens? (Note: those species born with no basic dependency on adults, such as the house fly, have ODR = 0)

Question 2: Can anyone think of other objective measurements for offspring dependency.

Question 3: Am I the only one who spent hours and hours in college debating such topics (e.g. without reference to any resources, debating how many earths would fit in the sun - a discussion which, after a period of 2 hours of debating, led to a roomful of 12 college guys pondering the question: how many mice could an elephant eat, if elephants ate mice)?

butswana

I read somewhere/saw on tv, that humans could be self sufficient in the wild by age five. Can't remember the specifics though.

joshack

I believe that chimps (and possibly orangs) are reasonably dependent on their parents/mother for a period of about 10 years. Your way of calculating this dependency does not implicate food-gathering or reproductive self-sufficiency (which are other ways to calculate it), instead more of a social self-sufficiency. In that case, I think chimps and elephants as well would give humans a run for their money.

As far as humans surviving independently at age 5, it's possible, but I think very unlikely, especially in a resource-scarce environment.

Coragyps

Quit picking on poor Dr Dino!!!