Complete the analogyMigration : Siberian Cranes :: ____________ : Bear

The correct answer is Option (2) → Hibernation

The analogy pairs a way of escaping unfavourable conditions with an animal that uses it. Siberian cranes migrate: they fly away from the Siberian winter to warmer places such as Keoladeo National Park in Rajasthan. A bear that cannot migrate escapes the winter in time: it sleeps through it.

Option (1) Regulation — Incorrect. Regulators keep their body temperature and salt balance constant by physiological means, as mammals and birds do. It is not a way of escaping the winter.

Option (2) Hibernation — Correct. In hibernation the animal goes into a deep winter sleep with very low body activity. Bears hibernate during winter.

Option (3) Aestivation — Incorrect. Aestivation is a summer sleep, used by some snails and fish to avoid heat and drying.

Option (4) Diapause — Incorrect. Diapause is a stage of suspended development, seen in many zooplankton of lakes and ponds.

Note: This question is from the topic “Responses to Abiotic Factors” in Chapter 13, Organisms and Populations, of the pre-rationalised NCERT book. This portion is not in the present NCERT book, where the chapter is now Chapter 11, Organisms and Populations. The extract below is from the pre-rationalised edition.

NCERT Extract (Pre-rationalised edition, Chapter 13, Organisms and Populations):
Responses to Abiotic Factors – “… (iii) Migrate : The organism can move away temporarily from the stressful habitat to a more hospitable area and return when stressful period is over. In human analogy, this strategy is like a person moving from Delhi to Shimla for the duration of summer. Many animals, particularly birds, during winter undertake long-distance migrations to more hospitable areas. Every winter the famous Keolado National Park (Bharatpur) in Rajasthan host thousands of migratory birds coming from Siberia and other extremely cold northern regions. (iv) Suspend: In bacteria, fungi and lower plants, various kinds of thickwalled spores are formed which help them to survive unfavourable conditions – these germinate on availability of suitable environment. In higher plants, seeds and some other vegetative reproductive structures serve as means to tide over periods of stress besides helping in dispersal – they germinate to form new plants under favourable moisture and temperature conditions. They do so by reducing their metabolic activity and going into a state of ‘dormancy’. In animals, the organism, if unable to migrate, might avoid the stress by escaping in time. The familiar case of bears going into hibernation during winter is an example of escape in time.”