Brain Size Linked to Maternal Care

Researchers at University College London and University of Cambridge say mammals with large brains may have evolved their larger brains due to the long-term investment of maternal care.

The British researchers focused on analyzing brain sizes of 197 marsupial mammals, such as kangaroos and possums, and 457 placental mammals, such as cats, dogs, and horses. They found marsupial brains to be of equal or even larger size than those of placental mammals.

A competing theory attributes larger brain size in mammals to metabolism. Physorg.org reported there has been such a focus on metabolic rate and brain size, that the role of maternal care has been overlooked. Dr. Anajali Goswami said, “If we take primates out of the equation, we discover that marsupials, despite having much lower metabolic rates, have similarly sized brains, or sometimes even bigger brains, than their placental mammal counterparts. So clearly, evolving big brains is not just about having a high metabolism. Instead, it seems maternal care is the most consistent factor driving the development of big brains across all mammals.” (Source: University College London)

Marsupial brains experience the most growth after birth, and placental brains during gestation. For marsupials, the British research may show the long lactation and period of maternal care is a critical phase of brain development.

Primate brains grow during gestation and after birth from maternal care. Research about metabolic rate in orangutans appears to be in alignment with British marsupial study. Orangutans were found to have a very low metabolic rate, and yet are one of the most intelligent mammals. Research from decades ago used inanimate fake mother figures with baby rhesus monkeys. It found the baby monkeys chose a non-feeding fake mother made from terry cloth over a wire fake mother which provided food. This research also found without the comforting aspect of a soft mother presence the babies experienced high stress, which interfered with their development.

Disclaimer: The views expressed above are solely those of the author and may not reflect those of
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colleen p.

7:15AM PDT on Aug 13, 2011

Melinda M. , like a grown man is going to care about a fake being? "you can have this body pillow, or a sex robot!!!!!!?????"

crule as it may be. it will show what is important. does the baby want food, or cuddles? cuddles were more important than food?

well one could argue if the TV makes a better baby sitter, mommy and teacher.

who wants to buy me some children and have them raised on various tv shows, with only electronic learning toys, talking books, video games and dollies for company. Just thow them some food, and see if they become derelects in comparision to children raised by educated, loving family where multi generation family raises and teaches them.

as for Marsupials not ruling the world. some think they are now out done by placental mammals.

send a green star

Debbie W.

8:49AM PDT on Jul 29, 2011

Yet another lesson from animals that points out how slow the human species really is. Scary.

KS G.

12:45AM PST on Jan 22, 2011

Thanks for the article.

Rhianna M.

10:45AM PST on Jan 21, 2011

Cute article! It's nice to hear interesting studies that aren't depressing. Along with others, I'd like to know how that affects humans. Thanks for sharing.

Melissah C.

5:05PM PST on Jan 4, 2011

thanks

Richard E C.

5:52AM PST on Jan 4, 2011

Who would ever know, very interesting.

Eternal G.

4:15PM PDT on Nov 3, 2010

So... why don't marsupials rule the world? Maybe they should research causality between placental vs. marsupial and agression? Nice looking pair of Brushtail Possums though, all bright eyed and bushy tailed!

johan l.

11:04PM PDT on Sep 21, 2010

Interesting article but no one has said how this would affect humans?

Darle W.

11:03PM PDT on Sep 20, 2010

I hope these researchers didn't have to hurt the animals to do the research.

1:16PM PDT on Sep 15, 2010

Hmm -- Maternal care affecting brain size -- questions spring to mind about so many people ...