I believe we can all agree a Great dane and a Chihuahua don’t exactly look alike, right? Yet, these two are in the same specie: Dog (Canis lupus familiaris). How are two very different looking dogs of the same specie?
There are so many stories and theories on dog selection, it’s not even funny. Some theories suggest Shih Tzu dogs came to be because people would keep their ancestors in cages. This would caused stunted growth or malformations contorting the body. Smaller dogs resulting from this horrendous practice were used to breed the next generations and so on. Eventually, a smaller breed of dog was created.
But not every theory suggests such heinous practices. Most of your current breeds came from selective breeding practices. Breeders saw a physical or behavioral trait they much appreciated and would try to find creative ways to display that trait in the next generation. A good working example of this in current use are your synthetic breeds like the Labradoodle.
Sometimes blending two species to create a new one can actually be beneficial. Far too often, homogeneity occurs within a particular breed because the same genes are used to breed the next generation. This is where your hip dysplasia on German shepherds or Labrador retrievers comes from.
Even so, let’s get back to some of these dog breeds. I think, rather than focusing on what makes one dog different from the next, let’s look at what makes them similar.
Dogs are similar in that they are genetically identical and have the same anatomical features.
Twenty things most dogs have in common:
- Fused wrist bones
- A cardiovascular system that supports both sprinting and endurance
- Teeth designed to catch and tear
- An appetite designed to scavenge
- They are predators
- They have 4 critical behavior patterns following birth.
- Most have patterns of countershading or a natural camouflage pattern on their fur
- They have a higher metabolism rate
- They have exactly 78 chromosomes (39 pairs) and one member of each pair comes from each parent
- Normal body temperatures are a range between 100 and 102.5ºF
- Dogs begin their lives with 28 deciduous teeth (teeth that fall out – like puppy teeth) which cut through at 6-to-8-weeks-of-age. When puppies reach 6-to-7-months-of-age these puppy teeth fall out and 46 permanent teeth take their place.
- Dogs have 319 bones in total
- Dogs, on average, posses 300-million olfactory receptors which is 40-times more than what humans possess.
- Dog’s sense of taste is poor in comparison to a human’s (this might explain why some dogs enjoy the occasional taste of poop).
- Dogs can actually shut off their inner ear to filter out distracting sounds. They can also register sounds coming in at 35,000 vibrations per second (compared to 20,000 vibrations per second for humans).
- Dogs have poor eye sight, a tapetum lucidium which gathers light to highlight images, and a third eyelid which is a protective membrane visible at the corners of eyes.
- Normal gestation times are 63 days.
- Female dogs have less difficulty conceiving and carrying a litter to term if they breed before the age of 5-years-old.
- Dogs growl when cornered and fearful (wolves will not do this)
- Puppies are born blind and deaf and remain this way until 10 to 14-days-old.
It’s easy to see there are many reasons why dogs are still dogs even though they look so different from one another. As different as their appearances are, there’s more commonality keeping them as one specie.
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