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A question of cuteness

Why baby animals are almost as appealing as baby humans

What is the thing that makes all young animals look cute to us humans? And do they generally look less cute when they mature?  Joe, Singapore

Baby animals (and some adults) look cute because they resemble baby humans. 

Humans feel a surge of affection for animal babies like their own, with large eyes, bulging craniums and retreating chins. Drawing courtesy of Wikipedia and Neitram.

The 1973 Nobel Prize winner zoologist Konrad Lorenz lists babyhood features that few can resist:  "A relatively large head, predominance of the brain capsule, large and low-lying eyes, bulging cheek region, short and thick extremities, a springy elastic consistency and clumsy movements."   Also, playfulness.  What human can watch tiger cubs wrestle or pounce on one another without a smile?

These characteristics distinguish our young from adults, and trigger an affectionate, nurturing response, Lorenz theorized.  It's basic; we must help our young survive, when they are least able to help themselves, or our species would die. 

Our species, however, changed to recognize our young's special features — not the other way around. 

Moreover, this ability to recognize immature members is general among primates and all mammals, emails biologist Michael C. LaBarbera of the University of Chicago.  Our species inherited its ability to recognize our young's special features.  Furthermore, "at least some species (including humans) seem to generalize this recognition of immatures.  [For instance,] Koko the gorilla adopted a kitten and, just a few years ago, a female gorilla at Chicago's Brookfield Zoo protected a child that had fallen into the gorilla exhibit."

Indeed, babies did not evolve to look or act cute.  Instead, primate bodies (and all mammalian bodies) develop in much the same fashion dictated by survival needs. 

For instance, a disproportionately large head houses a large brain.  Relative to body weight, a newborn macaque monkey's head is more than three times heavier than an adult's, writes anthropologist Adrienne Zihlman of the University of California at Santa Cruz.  Even at birth, a primate's brain contains the development a baby needs to survive.   He can see, hear, feel, smell and cling.  For the development he lacks — primarily muscles (for locomotion, finding food and protection) — he relies on his mother. 

In fact, all baby mammals have large heads, says LaBarbara, primarily because their bodies produce most brain nervous tissue while in utero.  Baby mammals have short snouts relative to cranium size; their snouts elongate as the animal approaches weaning.  Probably this is why squirrels seem cute.  Even as adults, they tend to have short snouts.

But the baby must change.  "All mammals go through a regular series of shape changes as they grow and mature," says LaBarbera.

As a primate becomes independent of his mother, his proportions change.  A newborn's body has almost equal amounts of skin, bone and muscle.  As he matures, the amount of skin and bone in his body shrinks relative to his entire body mass while his muscle-mass doubles (changing from 25 to 42% of total body mass), says Zihlman.  Now, an adult, he can handle life; he needs no triggered kindness.  And, in general, he doesn't look cute anymore. 

Further Reading:

D.R. Bolter and A.L. Zihlman. "Primate growth and development. A functional and evolutionary approach." Invited paper for Primates in Perspective, S. Bearder, C. Campbell, A. Fuentes, K. McKinnon, editors. Oxford University Press. 2006.

The biology of B_movie monsters by Michael C. LaBarbera, University of Chicago, Organismal Biology & Anatomy, Geophysical Sciences, the Committee on Evolutionary Biology

Konrad Lorenz. Part and Parcel in Animal and Human Societies, in Studies in animal and human behavior, vol. 2. pp. 115-195. Cambridge, Mass.: Harvard UP, 1971 (originally pub. 1950).

Readers contributed answers to this question.  The next question is:  Can an average person develop the skill to reliably detect liars?  Click here to give April your answer: Answer the question.  Deadline:  June 29.  We will publish the best answers on July 13.

Readers' Answers to the current question:

• The perception that immature animals are "cute" is a mechanism to curb our natural hunting instincts and allow our "prey" to mature to an age of procreation before we start hunting them for food.

  Humans are arguably the most successful and prolific predators in the history of planet Earth, no other species has been able to cause the types of mass extinctions that I have witnessed in my short lifetime, and immature animals are the easiest of prey. If something didn't stop us from eating animals before they're old enough to procreate we would quickly exhaust our supply of animal protein, a ready source for high-quality proteins which our metabolisms require to survive.

  If you believe in creation, it's easy to understand this as part of God's plan. If you believe in evolution, it's easy to see a group of humanoids without the "cute filter" would target immature animals for food, quickly wiping out species by species in their region until finally there would be no animals left. The lack of a high-protein food source would lead to a type of malnutrition we now know as Kwashiorkor, leading to a decline and eventual disappearance of the group and removing that group from the gene pool. Only the groups with the "cute filter" would survive and grow to contribute to our modern population.

  Rob Donelson, Texas, USA
   

• I have seen a show called The most extreme, in which they mentioned why teddy bears are so popular. They have big eyes, a wide space in between their eyes and hair and little mouths.

  All babies have traits similar to that so that humans will feel maternal towards them and raise them/keep them safe. It's pretty much a survival technique, though all animals get similar characteristics. I don't remember seeing other animals (unless they were recently mothers) taking pity on lone baby animals and raising them though.

  Elena K., Montreal, Quebec, Canada
   

• The appeal of younger animals to humans relates to our instinct to nurture, care-for, and love those that are too young to fend for themselves. When most of us see a young animal that is almost totally helpless, our maternal instinct kicks in and we have the urge to love and care for it because it cannot do so on it's own.

  One does tend to lose the original interest they had in the once so adorable animal after it gets older, because it has matured into something that can take care of itself, for the most part. We still find the domestic dogs and cats that we love so dearly to be adorable, due mainly to the fact that most of them wouldn't be able to survive a week without our help.

  Rihanna, Arkansas, USA

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(Answered May 11, 2009)