Assertion (A) : The mammals we see around do not hibernate. Reason (R) : Unlike other kinds of animals, mammals feed their young ones with milk.

Assertion (A) is false because many mammals do hibernate to survive extreme environmental conditions and food scarcity. Examples include bears, bats, and rodents like the Columbian ground squirrel [t1, t3]. These mammals enter a state of torpor or prolonged hibernation to maintain homeostasis and conserve energy [t1]. Reason (R) is true as a defining characteristic of mammals is that they possess mammary glands and nurse their young with milk [c1, t6]. While both statements involve mammalian biology, there is no causal link between lactation and the absence of hibernation. In fact, some mammals like brown bears even give birth and nurture their young with milk while in a state of hibernation, using fat and lean mass reserves to support the energetic costs of reproduction [t2]. Therefore, A is false but R is true.

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 9: Indian Biodiversity Diverse Landscape > Mammals > p. 154
2. [2] https://pmc.ncbi.nlm.nih.gov/articles/PMC4184349/
3. [3] https://www.sciencedirect.com/science/article/abs/pii/S0304380013004213