Laboratory Mouse
Caloric restriction extends their lives 30-40%, turning a two-year lifespan into nearly three.
Laboratory mice live fast and die young - heart rates at 600 beats per minute, eating half their body weight daily, lifespans of 2-3 years - making them perfect for studying what happens when you try to change that equation. Caloric restriction extends their lives 30-40%, turning a two-year lifespan into nearly three. This is the closest mammalian model we have for understanding whether humans can do the same, and the results are revealing: it's not just about eating less - it's about the cellular machinery that responds to scarcity.
Mice with broken autophagy genes don't benefit from caloric restriction at all. Mice given rapamycin - a drug that mimics some effects of CR - live 10-15% longer even when treatment starts late in life, equivalent to starting at human age 60. Overexpress SIRT6 and lifespan extends 15%. Reduce mTOR activity by 50% and lifespan jumps 20%. The mouse's rapid metabolism and short lifespan compress decades of human aging into months, making them evolution's gift to longevity research: iterate fast, measure lifespan extensions in years not decades, test interventions at scale.
But the speed comes with tradeoffs. Mice burn energy so fast relative to size that they must eat constantly - 50% of body weight daily versus an elephant's 2-3%. This is Kleiber's Law in action: metabolism scales as mass to the 0.75 power, meaning small animals are metabolically intense but inefficient per gram. The business parallel: rapid iteration cycles and short feedback loops let you test more, but high metabolic rates mean high operational costs. You can move fast or move efficiently, but rarely both.
Notable Traits of Laboratory Mouse
- 30-40% longer lifespan with caloric restriction
- ATG5 knockout mice show autophagy is required for CR benefits
- Rapamycin extends lifespan even when started late
- SIRT6 overexpression adds 15% lifespan (males)
- Darcin protein pheromone
- Pheromone-triggered memory formation
- Burns 50% body weight daily
- High metabolic rate per kilogram
- Weighs about 20 grams
- Eats ~50% of body weight daily
- Heart rate 500-600 bpm
- Heart rate ~600 bpm
- Bones ~5% of body mass
- Lifespan 2-3 years
- ~1.5 billion lifetime heartbeats (same as elephant)
Laboratory Mouse Appears in 5 Chapters
Mice show 30-40% longer lifespan with caloric restriction. Key findings: mice with broken autophagy don't benefit from CR; rapamycin extends lifespan 10-15% even when started late; SIRT6 overexpression = 15% longer; 50% reduced mTOR = 20% longer.
Longevity Interventions →Male mice produce darcin protein in urine, attracting females and triggering memory formation. Females remember locations where they detected the scent - demonstrating how chemical signals influence both immediate behavior and long-term memory.
Chemical Memory Formation →Small mammals with high metabolic rates per kilogram, burning up to 50% of body weight daily (vs. elephants at 2-3%). Illustrates Kleiber's Law: metabolism scales as mass^0.75 - larger animals more efficient per pound.
High Metabolic Rate Costs →Reference point for Kleiber's Law, sitting between shrew and larger mammals. At ~20 grams, requires eating ~50% of body weight daily with heart rate of 500-600 bpm.
Metabolic Reference Point →Small mammal in Kleiber's metabolic scaling research. Slender limbs with bones just ~5% of body mass (vs. 13-15% in elephants). Heart rate ~600 bpm. Lifespan ~2-3 years, following 'live fast, die young' pattern.
Scaling Law Demonstration →