Sarama is female and has always had that habit, though it was much worse before she was spayed. With her, it seems to be something of a dominance thing . . . but more in the bullying-you-because-you-will-let-me-get-away-with-it sense than in the I'm-trying-to-dominate-you sense. Social tension, or status-seeking, are probably better descriptions than 'dominance' honestly . . . especially since she's been spayed, I've almost taken it as 'neener-neener-neener you wimp!' than anything sexual, agressive, or even particularly dominant.