How many rats can live underwater? - briefly
Rats cannot sustain life underwater; they can hold their breath for only a few seconds to a minute before drowning. Consequently, the number that can live submerged is effectively zero.
How many rats can live underwater? - in detail
Rats are terrestrial mammals; their physiology does not support sustained respiration in a fully submerged environment. They possess lungs that require air, and while they can hold their breath for short periods, they lack the specialized adaptations seen in aquatic mammals such as blubber, streamlined bodies, or oxygen‑binding mechanisms that extend dive times.
Breath‑holding capacity
- Typical laboratory rat: 30–45 seconds of apnea at rest.
- Trained or conditioned individuals may extend this to approximately one minute, but performance rapidly declines with activity or stress.
Physiological limits
- Absence of a dorsal or ventral air‑filled cavity that can be compressed or expanded for buoyancy.
- No ability to extract dissolved oxygen from water; gill‑like structures are absent.
- High metabolic rate leads to rapid oxygen consumption, making prolonged submersion lethal.
Survival scenarios
- In shallow water (≤ 5 cm depth) a rat can remain afloat while breathing air at the surface; mortality occurs if the water level rises above the animal’s head for more than a minute.
- In experimental settings where rats are placed in water tanks, mortality rates approach 100 % after 2–3 minutes without rescue.
Conclusion
Under no circumstances can a rat live permanently underwater. The maximum duration any rat can survive beneath the surface is limited to about one minute of breath‑holding, after which hypoxia and drowning ensue. Consequently, the number of rats that can inhabit an underwater environment is effectively zero.