Which of the following families includes species which have retractable claws?

The family that includes species with retractable claws is Felidae. This family is commonly known as the cat family and encompasses various species, such as lions, tigers, and domestic cats. Retractable claws offer several advantages for these animals, including enhanced grip during climbing, improved hunting skills through stealth and precision, and the ability to keep claws sharp by retracting them when not in use.

The other families listed do not possess this characteristic. Canidae, which includes dogs, wolves, and foxes, have non-retractable claws that are always extended, allowing for better traction while running and hunting over varied terrains. The Ursidae family, comprising bears, also has non-retractable claws that are adapted for digging and climbing but do not retract. Mustelidae, which includes weasels, otters, and badgers, similarly features non-retractable claws, which assist with their various lifestyles, such as burrowing or swimming. Understanding the biology and adaptations of these families helps highlight the unique traits that allow each group to thrive in their respective environments.