question: how does animal age works and why its different than our age?
comment: Different animals have different lifespans. A dog, depending on the breed, may live 12 years, but human lifespan is about 85 years. Seven times as long. A middle aged dog is 7 years old. A middle aged person is 42 years old. That's 7 in dog years.
passages: BULLET::::- The other common system defines "dog years" to be the actual calendar years (365 days each) of a dog's life, and "human years" to be the "equivalent age" of a human being. By this terminology, the age of a 6-year-old dog is described as 6 dog years or 40–50 human years, a reversal from the previous definition.
  
  However, regardless of which set of terminology is used, the relationship between dog years and human years is not linear, as the following section explains.
  
  Section::::Aging profile.
  
  They can be summarized into three types:
   BULLET::::- A study on the pattern of extinction of the Irish elk, as indicated by radiocarbon data from fossil specimens from western and eastern Europe, is published by Lister & Stuart (2019).
  
  BULLET::::- A mandible of the giant muntjac ("Muntiacus gigas", considered by the authors to be synonymous with "M. vuquangensis") is described from the Late Pleistocene to Early Holocene deposits in the cave site of Hang Boi (Vietnam) by Stimpson "et al." (2019).
   In fact, the aging of a dog varies by breed (larger breeds tend to have shorter lifespans than small and medium-sized breeds); dogs also develop faster and have longer adulthoods relative to their total life span than humans. Most dogs are sexually mature by 1 year old, which corresponds to perhaps 13 years old in humans. Giant dog breeds and bulldogs tend to have the strongest linear correspondence to human aging, with longer adolescences and shorter overall lifespans; such breeds typically age about nine times as fast as humans throughout their lives.
  
  Section::::Time.:Galactic year.
   BULLET::::- A study on the diversity and the environments of hominins in the early Pleistocene of the Omo-Turkana Basin (East Africa) is published by Bobe & Carvalho (2019).
  
  BULLET::::- A study comparing ages at death of hominin specimens from the early Pleistocene sites of Drimolen and Swartkrans, and on their implications for inferring mechanisms of hominin skeletal accumulation at these sites, is published by Riga "et al." (2019).
   A chronology based on mammal taxa has been defined on all the continents except Antarctica. Because the continents have been separated through most of the Cenozoic, each continent has its own system. Most of the units are based on "assemblage zones", layers of strata that contain three or more distinctive fossils.
  
  Section::::Land mammal ages.:North America.
   Aging in dogs
  
  Aging in dogs ("Canis lupus familiaris") varies from breed to breed, and affects the dog's health, physical ability and life expectancy.
  
  As with humans, advanced years often bring changes in a dog's ability to hear, see and move about easily. Skin condition, appetite and energy levels often degrade with geriatric age, and medical conditions such as cancer, renal failure, arthritis, dementia, and joint conditions, and other signs of old age may appear.
   BULLET::::- A study of the phylogenetic relationships of the Paleocene placental mammals is published by Halliday, Upchurch and Goswami (2017).
  
  BULLET::::- A study on the impact of the Eocene Thermal Maximum 2 on the evolution of the body size in four placental lineages, especially in the early equid lineage "Arenahippus pernix", is published by D'Ambrosia "et al." (2017).
   BULLET::::- for Brown rat, 3.8
  
  BULLET::::- for dogs, 29 (See List of oldest dogs)
  
  BULLET::::- for cats, 38 (See List of oldest cats)
  
  BULLET::::- for polar bears, 42 (Debby)
  
  BULLET::::- for horses, 62
  
  BULLET::::- for Asian elephants, 86
  
  The longest-lived vertebrates have been variously described as
  
  BULLET::::- Large parrots (macaws and cockatoos can live up to 80–100 years in captivity)
  
  BULLET::::- Koi (a Japanese species of fish, allegedly living up to 200 years, though generally not exceeding 50 – a specimen named Hanako was reportedly 226 years old upon her death)
  
  BULLET::::- Tortoises (Galápagos tortoise) (190 years)
   BULLET::::- A study on the bone growth pattern of different-sized hipparionins as indicated by bone histology, and on its implications for inferring the possible mechanisms and causes underlying trends in size reduction of European hipparions in the late Miocene, is published by Orlandi-Oliveras "et al." (2018).
  
  BULLET::::- Review of fossils of members of the family Equidae from the Pleistocene site of lac Karâr (Algeria) is published by Sam (2018).
   Asian land mammal ages are more recently named and more tentative than the ages for the above continents, with poor geochronological constraints. There is no consensus for the names of some of the ages. However, the picture is rapidly improving, since Central Asia has some of the world's best records of Neogene mammals. In Africa, sequences of fossils (including those of primates) have been determined and some land mammal ages designated, but not yet formally defined.
  
  Section::::Land mammal ages.:Land-vertebrate ages.
   The terms "dog years" and "human years" are frequently used when describing the age of a dog. However, there are two diametrically opposed ways in which the terms are defined:
  
  BULLET::::- One common nomenclature uses "human years" to represent a strict calendar basis (365 days) and a "dog year" to be the "equivalent portion" of a dog's lifetime, as a calendar year would be for a human being. Under this system, a 6-year-old dog would be described as having an age of 6 human years or 40–50 (depending on the breed) dog years.
   Section::::Geology.:Principles of relative dating.:Faunal succession.
   My Life in Dog Years
  
  My Life in Dog Years is a non-fiction book for children written by the American author Gary Paulsen, together with his wife, Ruth Wright Paulsen. It was published first by Delacorte Press in 1997.
  
  The book contains a chapter about each different dog in his life. As he goes through each chapter, he delves into the personality of each dog as companions and not just animals.
   The regular term of service of a member of the Commission is 6 years. Members can be re-elected up to a total of three full six-year terms in a row. After 18 continuous years of elected service, a break of at least 3 years is prescribed before the member can stand again for election.
  
  Section::::Activities.
   The graph below represents the length growth per year of FHSM VP-2187 according to Shimada (2008)
  
  Section::::Paleobiology.
  
  Section::::Paleobiology.:Prey relationships.
   BULLET::::- Aging
  
  BULLET::::- List of oldest dogs
  
  BULLET::::- Old age
  
  BULLET::::- Pet loss
  
  BULLET::::- Dog year
  
  Section::::External links.
  
  BULLET::::- Convert Dog years and Human years (Basic and Advanced methods)
  
  BULLET::::- Dog Years Calculator – Uses Pets.WebMD.com method of calculation
  
  BULLET::::- From petplace.com:
  
  BULLET::::- Index of articles on senior and geriatric dogs
  
  BULLET::::- A compilation of dog longevity data from multi-breed and single-breed surveys (K. M. Cassidy)
  
  BULLET::::- Dog/Human Age Calculator
  
  BULLET::::- Dog/Human Age Calculator and Guidance (courtesy FPSI French Property)
  
  BULLET::::- A discussion of factors that affect dog aging that includes a table to help determine age 
   In general, dogs age in a manner similar to humans. Their bodies begin to develop problems that are less common at younger ages, they are more prone to serious or fatal conditions such as cancer, stroke, etc., they become less mobile and may develop joint problems such as arthritis, and in old age often become less physically active and may even develop dementia. Additionally, they become less able to handle change, including wide climatic or temperature variation, and may develop dietary or skin problems or go deaf. In some cases incontinence may develop and breathing difficulties may appear.
   The aging profile of dogs varies according to their adult size (often determined by their breed): smaller dogs often live over 15–16 years, medium and large size dogs typically 10 to 13 years, and some giant dog breeds such as mastiffs, often only 7 to 8 years. The latter reach maturity at a slightly older age than smaller breeds—giant breeds becoming adult around two years old compared to the norm of around 12–15 months for other breeds.
  
  Section::::Terminology.
   BULLET::::- A study on the age of the fossils of "Siderops kehli" is published by Todd "et al." (2019).
  
  BULLET::::- A study on long bone histology of specimens of the cryptobranchid species "Eoscapherpeton asiaticum" of different age is published by Skutschas "et al." (2019).
  
  BULLET::::- A study on the life history of the cryptobranchid "Aviturus exsecratus" from the Paleocene of Mongolia will be published by Skutschas "et al." (2019).
   BULLET::::- Size/breed specific calculators – These try to factor in the size or breed as well. These are the most accurate types. They typically work either by expected adult weight or by categorizing the dog as "small", "medium", or "large".
  
  No one formula for dog-to-human age conversion is scientifically agreed on, although within fairly close limits they show great similarities.
   Section::::Analyzing age class structure.
   The mesowear method or tooth wear scoring method is a quick and inexpensive process of determining the lifelong diet of a taxon (grazer or browser) and was first introduced in the year 2000.
  
  The mesowear technique can be extended to extinct and also extant animals.
   The first modern theory of mammal ageing was formulated by Peter Medawar in 1952. This theory formed in the previous decade with J. B. S. Haldane and his selection shadow concept. Their idea was that ageing was a matter of neglect, as nature is a highly competitive place. Almost all animals die in the wild from predators, disease, or accidents, which lowers the average age of death. Therefore, there is not much reason why the body should remain fit for the long haul because selection pressure is low for traits that would maintain viability past the time when most animals would have died anyway.
   BULLET::::- 1993 - 10th Biennial Conference, Galveston, Texas, USA, 11–15 November
  
  BULLET::::- 1991 - 9th Biennial Conference, Chicago, Illinois, USA, 5–9 December
  
  BULLET::::- 1989 - 8th Biennial Conference, Pacific Grove, California, USA, 7–11 December
  
  BULLET::::- 1987 - 7th Biennial Conference, Miami, Florida, USA, 5–9 December
  
  BULLET::::- 1985 - 6th Biennial Conference, Vancouver, British Columbia, Canada, 22–26 November
  
  BULLET::::- 1983 - 5th Biennial Conference, Boston, Massachusetts, USA, 27 November - 1 December
  
  BULLET::::- 1981 - 4th Biennial Conference, San Francisco, California, USA, 14–18 December
  
  BULLET::::- 1979 - 3rd Biennial Conference, Seattle, Washington, USA, 7–11 October
   Section::::History.
  