Winter hibernation and spring reproduction in bears are cued by seasonal changes in the secretion of
A) melatonin from the pineal gland.
B) melatonin from the hypothalamus.
C) thyroxine from the anterior pituitary gland.
D) acetylcholine from the pineal gland.
E) thyroid-stimulating hormone from the posterior pituitary gland.

Question

Quizplus · Accepted Answer

Melatonin secretion from the pineal gland is responsible for regulating seasonal behaviors in many animals, including bears. In the winter, melatonin secretion increases, leading to hibernation. In the spring, melatonin secretion decreases, triggering reproduction.

Therefore, the best choice is A) melatonin from the pineal gland.

Winter Hibernation and Spring Reproduction in Bears Are Cued by Seasonal