<human>:  Why do Rocky Mountain locusts have such a long lifespan?
<bot>: The Rocky Mountain locust has a lifespan of about a year. They are the largest locust in the world, and they can grow up to 1 meter (3 feet) long. They are also one of the fastest animals in the world. Their legs can reach speeds of up to 35 miles per hour (56 km/h).