How do domestic rats die of old age? - briefly
In senior pet rats, death usually follows age‑related organ degeneration—commonly kidney failure, heart disease, or cancer—that leads to systemic collapse.
How do domestic rats die of old age? - in detail
Domestic rats typically live 2 to 3 years, with some individuals reaching 4 years under optimal care. As they age, cellular senescence and cumulative DNA damage reduce the regenerative capacity of tissues. The cardiovascular system shows thickening of arterial walls, diminished contractility of the heart muscle, and a higher incidence of arrhythmias. Pulmonary function declines due to loss of alveolar elasticity, making oxygen exchange less efficient.
Metabolic changes include reduced insulin sensitivity, altered lipid profiles, and decreased appetite, leading to weight loss and muscle wasting (sarcopenia). The gastrointestinal tract slows, resulting in constipation and a higher risk of intestinal obstruction. Renal function deteriorates, with glomerular filtration rates dropping and the likelihood of chronic kidney disease increasing.
Common terminal pathologies observed in aged laboratory and pet rats are:
- Neoplastic growths (especially mammary adenocarcinomas, lymphomas, and hepatocellular carcinoma)
- Severe heart failure (congestive or dilated cardiomyopathy)
- Chronic kidney failure (uremia, electrolyte imbalance)
- Pulmonary disease (emphysema, bronchopneumonia)
- Severe infections (sepsis secondary to opportunistic bacteria or fungi)
When organ systems can no longer maintain homeostasis, rats exhibit lethargy, hypothermia, and loss of righting reflex. Death often follows a cascade: cardiovascular collapse → reduced cerebral perfusion → respiratory arrest. Post‑mortem examinations frequently reveal multi‑organ atrophy, widespread fibrosis, and the presence of one or more malignant tumors.
Preventive care—balanced diet, regular health checks, and environmental enrichment—delays but does not prevent the inevitable physiological decline that culminates in natural mortality.