Thermal Tolerance
An organism's ability to survive and function across a range of temperatures, from cold to hot extremes.
The range of temperatures within which an organism can survive, grow, and reproduce. It reflects the physiological limits set by an animal's or plant's biochemistry and evolutionary history. Species with narrow thermal tolerance are vulnerable to climate shifts; those with broad tolerance are more adaptable to temperature fluctuations.
What this means in real life
A penguin can survive in Antarctic waters near freezing but would die if moved to a tropical ocean; a desert lizard thrives in 50°C heat but cannot function in a cold climate. Each has evolved thermal tolerance suited to its native environment.
What it isn’t
It is not the same as heat resistance or cold hardiness alone. Thermal tolerance describes the full spectrum of survivable temperatures, not just endurance of one extreme.
Commonly misused online
Often conflated with 'climate adaptation'—people assume high thermal tolerance means an animal can easily adapt to climate change, when it actually just describes current physiological limits that may be fixed.