A naked mole rat colony, like a beehive, wasp's nest, or termite mound, is ruled by its qu

een, or reproducing female. Other adult female mole rats neither ovulate nor breed. The queen is the largest member of the colony, and she maintains her breeding status through a mixture of behavioral and, presumably, chemical control. Queens have been long-lived in captivity, and when they die or are removed from a colony one sees violent fighting for breeding status among the larger remaining females, leading to a takeover by a new queen.

Eusocial insect societies have rigid caste systems, each insect's role being defined by its behavior, body shape, and physiology. In naked mole rat societies, on the other hand, differences in behavior. are related primarily to reproductive status (reproduction being limited to the queen and a few males), body size, and perhaps age. Smaller non-breeding members, both male and female, seem to participate primarily in gathering food, transporting nest material, and tunneling, larger non-breeders are active in defending the colony and perhaps in removing dirt from the tunnels. One work has suggested that differences in growth rates may influence the length of time that an individual performs a task, regardless of its age.

Cooperative breeding has evolved many times in vertebrates, but unlike naked mole rats, most cooperatively breeding vertebrates (except the wild dog, Lycaon pictus) are dominated by a pair of breeders rather than by a single breeding female. The division of labor within social groups is less pronounced among other vertebrates than among naked mole rats, colony size is much smaller, and mating by subordinate females may not be totally suppressed, whereas in naked mole rat colonies subordinate females are not sexually active, and many never breed.

Which of the following most accurately states the main idea of the passage？

A．Naked mole rat colonies exhibit social organization based on a rigid caste system.

B．Behavior. in naked mole rat colonies may well be a close vertebrate analogue to behavior. in eusocial insect societies.

C．The mating habits of naked mole rats differ from those of any other vertebrate species.

D．Naked mole rat colonies are the only known examples of cooperatively breeding vertebrate societies.