Grizzly bears hibernate. Their behaviors are closely synchronized with the seasons. 灰熊会冬眠。它们的行为与季节变化紧密地保持一致。 During the summer, they have to pack on enough body fat to survive the winter. 在夏季,它们必须储存足够的身体脂肪,以度过冬天。 Without it, they would either starve...