Paedomorphism
Paedomorphism, also known as ‘Neoteny’, is the retention of
juvenile traits into adulthood. That is, those features that we associate with
infants and babies is carried through into adulthood and do not mature as would
normally be expected. It is these features which we focus on when we are
describing someone or something as being “cute” “baby-faced” or “adorable.” All
words which are warm and fuzzy and get our maternal and paternal emotions
heated up. Below is a diagram which summarises the main features that are considered
paedomorphic. Large eyes in relation to face size and a large domed head
disproportional to the body are what I would consider the most obvious features
that can be recognised in paedomorphic individuals.
Anything can be paedomorphic, from humans, animals to even
inanimate objects such as toys. A very interesting article I recently read has
shown that paedomorphism has been influencing toy makers. The old ‘Barbie’
dolls and ‘My Little Pony’ toys used to look very similar to adults and mature
horses, in terms of their proportions and features. In today’s world however
paedomorphosis has taken over and now we are seeing dolls such “Bratz” which
have enormous eyes, tiny mouths and large heads in comparison to their bodies.
This is the same with the modern “My Little Pony” toys who also have the
exaggerated large eyes and domed foreheads.
It seems the toy makers have found a money maker in getting
the “cute factor” in their products. Studies have shown that humans find
paedomorphic features more attractive whether that be in humans, animals or
even teddy bears and we will subconsciously choose to look at that face over a
mature face. This is mostly put down to the infantile features tickling our
subconscious need to care for a younger individual. If you want to look up more
about the history of Neoteny then do a good old wiki search and you will come
across a very interesting and useful page explaining pretty much everything you
need to know. What I will be doing here is relating paedomorphism to our good
old canine companion.
If any of you have watched the BBC Horizon programme on dogs
(It was a couple of years ago. But I’ve found a youtube link for anyone
interested in watching..) paedomorphism or neoteny in domestic dogs was
mentioned and it was this that first sparked my interest in this topic. It has
been documented that our domestic dog species exhibit a large amount of
paedomorphism and are likened to juvenile wolves. This can be in their
behaviour as well as their aesthetics. The best examples of neoteny are the
dogs in the toy group e.g. the Cavalier King Charles Spaniel, Chihuahua,
Pekignese, Yorkshire Terrier, and Pug to name a few. This can be seen quite
clearly; Lets take the pug for example,
When you compare their faces with the cartoon above you can
see that they have a large domed head, large eyes and small noses and mouths
(so small infact that they have difficulty breathing, but that’s another
topic..). And that is exactly the reason why dogs like the pug, and those
others listed are considered the “cutest” of the dog breeds and are
specifically companion dogs rather than working dogs, because they are
reminding us of human infants. They are ticking all the boxes in terms of
replacing a human child and that is why they are nutured so much. Perhaps a
little more than they need to be at times…
So our dog breeds are very cute, and we love them. That I do
not deny. But what happens when you select of paeodmorphism? What happens when
you selectively breed an animal to retain infantile or juvenile features. In
turns out there are a lot of inadvertant results from producing something
adorable. But I’d like to start this by first reversing the question, which
takes me to one of my favourite studies in canids:
The silver foxes of
Russia. Scientists in Russia wanted to learn more about the domestication
of canines and so took a population of silver foxes and began selectively
breeding them. They took the tamest foxes and bred them, and selectively only
breeding from the next generation who were also tame. As generations continued
they did produce a population of foxes who were extremely tame and began
showing very dog like behaviours such as wagging their tails when a human
approached etc. This was very exciting as it was the first evidence that there
is a “tame” gene. To confirm this was not by chance they also selectively bred
from the most un-tame or aggressive foxes and produced a completely opposite
population of foxes who would not accept any human contact and were even
described as “Dragons” by the scientists. How this links to paedomorphism is
the tame foxes began to change in their appearance. They stayed looking like
fox cubs for longer and even began developing features we most often relate to
dogs such as patchy coats, and big floppy ears.
This fascinates me. It seems that by selecting for a tame
gene you have inadvertatly produced a paedomprhpic individual. Or if you look
at it from a different angle, you get tame individuals by choosing animals who
have degrees of paedomorphism to start with….So paedomorphism has a link to
tameness. This is supported by other behavioural studies who have shown that
the more paedomorphic breeds like the Cavalier King Charles Spaniels have fewer
behavioural repertoires and were more likely to approach unknown dogs in a
playful manner like puppies compared to dogs like the German Shepherd who
approached with more caution and showed a wider range of behavioural
repertoires. Whats more, the communication between the dogs is affected by
paedmorphism, and this can be visually observed. Just take a moment to think
about the amount of subtle body language us humans are capable of.. Dogs have
this too. Or more to the point, wolves are capable. A wolves body language can
range from a slight twitch of the upper lip, a complete snarl, an ear pinning
back against the skull, ears perked forward, tail up and bushy etc. etc. And
this is extremely important in the pack to settle hierarchy and communicate
with other wolves. But our paedmorphic breeds lack the features to do this. The
pug cannot erect its tail, a springer spaniel cannot perk its ears up, a
pekignese would struggle with a lip twitch due to its condensed face etc. So by
selecting for paedomorphism, while they are aesthetically pleasing out beloved
dogs have lost the ability to communicate as successfully as their ancestors
would.
Is behaviour the only thing altered by the loveable faces?
Sadly no. There is a great deal of evidence that almost all of us know by now
is that changing the morphology of dogs in the way paedomphism does can have
devastating consequences on their health. The pug and its breathing is just the
start, there are eye problems, dental problems, and the one close to my heart,
neurological disorders that occur from the infantile head.
The Cavalier King Charles Spaniel suffers from Chiari-like
Malformation (CM). This is a condition where the occipital bone of the dogs
skull forms too quickly and fuses too early, so the cerebellum of the brain
grows too big for the skull and herniates. From this Syringomyelia (SM) can
develop which is fluid filled vesicles collecting along the spinal cord. These
can result in devastating clinical signs causing the animal horrendous pain and
suffering. And why does it occur? Because we have changed the Cavaliers skull
shape to benefit our visual desires. In order to get a paedomorphic head the
skull needs to change in a way that the skull remains domed and doesn’t grow
with the skeleton as in normal maturation. In the Cavalier this has resulted in
CM and SM.
The Cavalier King Charles Spaniel is an amazing breed of
dog, which the best temperament and is an extremely sweet looking dog. But it
has all come at a terrible cost, to which I would even say the breed should not
exist at all…I am very interested in paedomorphism and would love to find out
more about how using it as a selective pressure can alter our dogs, in hope
that we can find ways to reverse the adverse consequences. My dissertation has
excitingly shone light upon the idea that gait may also be affected in
paedomorphic breeds and I am hopefully on the next few steps to publishing this
data. But we will have to wait and see for that..
