In winter, when temperatures dip below freezing and food supplies dwindle, some animals enter hibernation—an inactive state in which metabolism nearly stops, body temperature drops, and heart rate may slow to one or two beats a minute. Though the exact stimulus that triggers hibernation is unknown, infusing an extract from the blood of a hibernating animal into an active potential hibernator has been shown to induce hibernation, indicating that the cause may be blood-borne. What is estivation? Discuss
Source: The Free Dictionary