MCQ Detailed View

Animals can be categorized based on how they regulate their body temperature. They are generally divided into ectotherms (cold-blooded) and endotherms (warm-blooded). Hummingbirds belong to the endotherm category.

An endotherm is an organism that can generate and maintain its body heat internally, independent of the surrounding environmental temperature. Birds and mammals are the main groups of endotherms. They achieve this through a high metabolic rate, burning energy from food to produce heat. This allows them to remain active in different climates, even in cold conditions where ectothermic animals would slow down or become inactive.

Hummingbirds, among the smallest birds in the world, have extremely high metabolic rates to support their rapid wing movements, which can beat up to 70–80 times per second. To sustain this energy demand, they consume large amounts of nectar and small insects, converting the energy quickly into heat and muscle power. Their internal body temperature typically stays around 40–42°C (104–107°F), much higher than the surrounding air on cooler days.

The other terms in the options refer to:

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  Ectotherm: Animals like reptiles and fish that depend on external heat sources to regulate body temperature.

  
  


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  Exotherm: Not a standard biological classification; sometimes used informally for heat-releasing reactions.

  
  


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  Heterotherm: Animals that can switch between endothermic and ectothermic states, like bats or some small mammals during hibernation.

  
  

Hummingbirds cannot survive without maintaining a high, stable body temperature. Although they can enter a state of torpor (temporary low metabolism at night to save energy), they are fundamentally endothermic animals, actively generating heat most of the time.

Hence, the correct answer is Endotherm, as hummingbirds are warm-blooded birds with high metabolic energy production.