What unique ability does Cope's gray tree frog have?

What unique ability does Cope's gray tree frog have?

• A. It can freeze and survive the winter.
• B. It can change color rapidly.
• C. It lays eggs only in spring.
• D. It sings to attract mates underwater.

Answer: (A)

Freeze tolerance in amphibians is what this question is about. Cope's gray tree frog can survive winter by letting part of its body freeze and then thaw in spring. When cold sets in, ice forms in extracellular spaces while the frog protects its cells with cryoprotectants, especially glucose released by the liver. This lowers the risk of intracellular ice, slows metabolism to a near-hibernation state, and keeps vital systems from failing despite the freeze. When warmth returns, the ice melts, the heart and breathing resume, and normal life continues. So the unique ability is that it can freeze and survive the winter. The other traits listed are not distinctive features of this species.

Freeze tolerance in amphibians is what this question is about. Cope's gray tree frog can survive winter by letting part of its body freeze and then thaw in spring. When cold sets in, ice forms in extracellular spaces while the frog protects its cells with cryoprotectants, especially glucose released by the liver. This lowers the risk of intracellular ice, slows metabolism to a near-hibernation state, and keeps vital systems from failing despite the freeze. When warmth returns, the ice melts, the heart and breathing resume, and normal life continues. So the unique ability is that it can freeze and survive the winter. The other traits listed are not distinctive features of this species.