Monday 9 July 2012

Word of the day - Pedomorphosis

I enjoy learning new words and sometimes you come across a really good one! Pedomorphosis is not as bad as it sounds and was being used in the context of why dogs are not as aggressive as Wolves. Basically, it means changing into a child.

The explanation is quite nice as well: Used in the context of dogs, it describes the phenomenon that domestic dogs actually show lots of the same behavioral traits as Wolf pups but remain forever in that ancestral puppy-like state while real Wolves go on to develop their classic behaviors and aggression. Barking is an example - adult Wolves don't bark but prefer howling. Barking is a Wolf pup behavior associated with begging for food or play for instance. Whining and submissivness would be other examples. So our domesticated dogs are really just retarded Wolves! It goes further too with the concept of Neoteny where toy Dog breeds actually start to look like neonatal (newborn) Wolves.

So why does this happen? It seems that it is actually concomitant with domestication as demonstrated by the Farm-Fox experiment (web page)(pdf) - a lifelong project in domestication for Dmitry Belyaev started in 1959 and still ongoing 27 years after his death. By breeding Silver Foxes (Vulpes vulpes) and selecting for tameness, a number of morphological, biochemical and behavioral changes were noted over just a short number of generations (~30). These included increased prevalence of piebald coat colour and curly fur, floppy ears and shortened, curly tails for morphological traits and significant (>75%) reductions in corticosteroid plasma levels (corticosteroids act as stress hormones - this is presumably related to aggressiveness). Some of the morphological  changes were greater than 1000% (10 times) compared to the non domesticated population and up to 7000%! All of this has been associated with the creation of a population of very tame animals in an evolutionarily short space of time.

Photo (CC)- TRiver

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