On the Aging of Species
By Christine J. Charvet
Research into comparative aging in humans and other primates is offering clues about diseases, development, and evolution.
This Article From Issue
September-October 2026
Volume 114, Number 5
Page 298
Most of us have heard that we can calculate a pet's human-equivalent age by multiplying by seven. But the truth is more complex and far more fascinating. Across species, including our fellow mammals and closer primate cousins, development and aging may unfold at different rates, with some life stages compressed while others are stretched. Because age strongly shapes disease risk, identifying corresponding ages across species can help guide the design of age-appropriate treatments that are relevant to both animals and humans. Therefore, understanding how human developmental milestones compare with those of other animals could advance our understanding of health and disease. The problem lies in figuring out how to make those comparisons.
QUICK TAKE
- Mammals age quite differently, with milestones occurring at different ages and developmental stages taking more or less time in one species compared with another.
- Translating ages among species and across the lifespans of humans and other mammals requires integrating numerous lines of evidence from brain, body, and behavior.
- Insights about aging could guide medical research and aid in the design of treatments for age-related diseases that affect humans and other animals.
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