Cockroaches have six legs with tiny spines on them, two long antennae, and a broad head with chewing mouthparts. The nymphs (immature cockroaches) are smaller than the adults and may be gray or brown in color. Some species can also fly, although not all do. Regardless of their size or color, most cockroaches have a characteristic musty odor that is produced by special glands in their body. Additionally, some species of cockroaches may hiss or chirp when disturbed.