As we well know, different breeds of dogs have different characteristics that affect their anatomy and behavior, among other aspects. One of them is life expectancy, since generally speaking small breed dogs live longer than those of large breed. Today, science relates the effects of free radicals with this fact and studies other theories.
The Colgate University Study
At the beginning of the year, the results of a study carried out by Josh Winward and Alex Ionescu, from Colgate University in New York. His team collected about 80 tissue samples from recently deceased puppies and adult dogs, both large and small breeds. They isolated the cells from these remains and cultured them in the laboratory for analysis.
With this, they found that the metabolism of large breed puppies is faster, since it consumes a huge amount of energy compared to small dogs. This causes an elevation of their levels of free radical, which can lead to cell damage, since its production of antioxidants to combat them is not enough. All this shortens the life of the animal.
A hormonal issue
Another theory relates the hormone called IGF-1, also known as growth factor 1, present in all mammals. It is responsible for stimulating cell growth and multiplication, so any alteration in it influences the size of the animal. In turn, it is associated with diseases such as cancer and cardiovascular problems. Smaller dogs have lower levels of this hormone, which could explain why they age more slowly than large breed dogs.
Heart size relative to body mass
In proportion to their size, large dogs have the smallest heart than smaller breeds. There is an unproven theory that relates the life expectancy of large dogs with the fact that they have to pump a greater amount of blood for their body, so their heart suffers more.