Why can evolution in mosquitoes be more easily observed than evolution in a population of squirrels?

Mosquitoes have a short lifespan and often die quickly due to humans, animals, or environmental causes. They also reproduce in a way that makes it easy to mate and to have as many offspring as possible. And due to their short lifespans, mosquitoes mate a lot more than squirrels.

Squirrels have longer lifespans and life expectancy and mate more like us, in a breeding season.