1.   First, while puppies of a given breed may look almost exactly alike, there can be wide behavioral differences among individuals within a single litter.

2.   It is hard to think of another behavioral difference so observable and so fundamental that has not been explained.

3.   Now, scientists think they know why, and the answer offers a rare example of a behavioral difference linked to a single gene.

4.   Perhaps the best explanation lies in behavioral differences between boys and girls.

5.   She says she breaks with some feminists in believing the scientific evidence suggests that a few behavioral differences between men and women are innate.

6.   The researchers, writing in Nature, suggest that the behavioral differences are due to differences in the abundance and distribution of food in the two seas.

7.   What are the behavioral differences among gorillas of the same subspecies, but differing environments?

8.   When I was growing up, the sartorial similarities between good girls and bad girls did not erase the behavioral differences.

9.   While scientists stop short of calling the underground bugs a new species, they say the behavioral differences are stark.