Which of the following animals is known to be nocturnal?

Bats are known to be nocturnal, meaning they are primarily active during the night. This behavior has evolved as a survival strategy, allowing bats to feed on insects that are also more abundant during nighttime hours. Their echolocation abilities help them navigate and hunt in complete darkness, which gives them a distinct advantage over diurnal animals that are active during the day.

Frogs, while they can be active at night, are not exclusively nocturnal; many species can be active during the day as well. Snakes vary widely in their activity patterns depending on the species, with some being diurnal and others being nocturnal. Chipmunks are typically diurnal, actively foraging during daylight hours. Therefore, while other animals may exhibit some nocturnal behavior, bats are the most well-known and specialized for night activity among the options provided.