Age in Human Years

Notes

• Where this number comes from, and what it is not. There is no official conversion for goats the way there is for dogs and cats, whose charts come from veterinary bodies. This figure is built by anchoring on two things that are documented — a goat is adult at about 9 months, and lives on average about 16 years — and mapping those onto 18 and 80 human years, interpolating between. Every honest chart of this kind is built the same way; most simply do not say so.
• Goats keep growing new teeth until about four, and the number of adult incisors is how their age is read — a "four-tooth" or "full-mouth" goat is a statement of age, not of dentistry. After that the teeth wear and spread, and a "broken-mouth" goat is an old one.
• Averages hide most of what decides an individual life. The recorded maximum for a goat is around 22 years, roughly 1.4 times the average. Housing, diet, whether the animal is neutered, and whether problems are caught early move an individual far more than the species average suggests.
• Ageing is not linear, and that is the whole reason a conversion is needed. A goat does most of its growing up in the first few months, then ages slowly. Dividing a lifespan by a single number gives the wrong answer at both ends — which is why the figure above bends at maturity rather than running straight.