Since Jack Russell Terriers are loyal, affectionate, and hyperactive dogs, they can give you company when going out to hunt or exercise. With the following Jack Russell Terrier: size comparison to human guide, you’ll understand how your size relates to that of JRTs, so you don’t end up exhausting it.
Jack Russell Terrier: Size Comparison to Human
The life expectancy difference between humans and dogs poses a challenge when comparing their sizes. For instance, there is a significant size difference between a 3-month-old and a one-year-old JRT, while there is no significant difference between a 3-month-old child and a one-year-old child.
Although the life expectancy of a JRT might vary depending on the diet, health condition, and genes, JRTs have an average lifespan of around 13 to 16 years and are considered to be fully grown after one year.
On the other hand, the average lifespan of a human in the US is 78.79 years and humans are considered fully grown after around 25 years. Converting the various ages of JRTs to human years gives the following size and weight differences between humans and JRTs of varying ages.
Due to the lifespan difference between dogs and humans, the first year of a dog’s life is equivalent to 15 human years. A three-month-old JRT has a height of around 4 to 7 inches and weighs around 6 to 8 pounds.
When you convert this age to human years using the simple math: 3 x 15 / 12, this age is equivalent to a 3.75-year child. On the other hand, the average size and weight of a 4-year-old kid are around 40 inches tall and weigh approximately 40 pounds.
A 6-month-old JRT is around 11 to 14 pounds and stands around 10 to 12 inches. Again, you will need to convert this age to human years to get the equivalent age of a human being.
6 x 15 / 12 gives us an equivalent age of a 7.5-year-old child. Considering that children tend to grow for around 2 to 3 inches and gain around 4 to 5 pounds per year, an 8-year-old kid has an average height of around 50.5 inches and weighs about 57 pounds.
Keeping in mind that a 12-month-old JRT is considered mature, a 9-month-old JRT is the equivalent of a human teen. Usually, a 9-month-old JRT weighs around 12 to 16 pounds and stands 11 to 14 inches.
In most cases, you won’t notice any size difference between a male and female JRT of this age. On the other hand, 9 x 15 /12 gives an equivalent age of an 11.25 years teenager. In most cases, female teens tend to be slightly bigger and heavier than their male counterparts.
Teen girls weigh around 91.5 pounds and have a standing height of about 59 inches. On the other hand, a teen boy weighs around 88 pounds and has a standing height of about 58.7 inches.
A one-year-old JRT is considered to be fully grown, and in most cases, it will have attained the maturity weight of 13 to 17 pounds and a standing height of 11 to 15 inches. Unlike the previous conversions, a one-year-old JRT is comparable to a mature human aged 20 to 25 years.
In most cases, a 20-year-old man will be heavier than a 20-year-old woman. 20-year-old men have an average standing height of 69.7 inches and weigh around 155 pounds. On the other hand, 20-year-old women have an average standing height of 64.3 inches and weigh around 128 pounds.
In most cases, both JRTs and humans maintain these sizes and weights for the rest of their lifespan. However, both older people and senior JRTs might start losing weight during the last days of their lifespan.
Factors That Affect the Sizes of JRTs and Humans
Although there is a significant difference between the size of a JRT and a human, the following factors can affect how big both humans and JRTs can grow.
- Genetics: The size of both JRTs and humans depends on the ancestry history and gene combinations
- Health: Different health conditions can affect both JRTs and humans and cause growth and development issues
- Diet: Malnourishment can cause stunted growth in both humans and JRTs
Are Humans and JRTs Prone to Obesity?
Yes, humans and JRTs can be prone to obesity depending on their diet. Usually, obesity results from a high-calorie diet and lack of exercise, which both JRTs and humans can be prone to.
Is a Mature JRT Heavier Than a Newborn Baby?
Yes, a mature JRT is heavier than a newborn baby. Usually, a mature JRT weighs around 13 to 17 pounds, while a newborn baby weighs around 7 to 8 pounds.
The Jack Russell Terrier: Size Comparison to human guide reveals the size differences between a JRT and a human at different life stages. Remember to convert the dog’s age to human years to get a realistic size comparison.