Females can sting, but will only do so if bothered. Males appear aggressive as they fly around people and pets, but they are not harmful since males do not have a stinger.
Carpenter Bees
Non-professionals commonly confuse carpenter bees with bumblebees; the simplest rule of thumb for telling them apart is that most carpenter bees have a shiny abdomen, whereas bumblebee abdomens are completely covered with dense hair. Males of some species of carpenter bees have a white or yellow face, unlike bumblebees, while females lack the bare corbicula of bumblebees; the hind leg is entirely hairy.
Carpenter bees make nests by tunneling into wood, bamboo, and similar hard plant material such as peduncles, usually dead. They vibrate their bodies as they rasp their mandibles against hard wood, each nest having a single entrance which may have many adjacent tunnels. As a subfamily, they attack a wide range of host plants, but any one species may show definite adaptations or preferences for particular groups of plants. The entrance is often a perfectly circular hole measuring about 16 mm on the underside of a beam, bench, or tree limb. Carpenter bees do not eat wood. They discard the bits of wood, or reuse particles to build partitions between cells. The tunnel functions as a nursery for brood and storage for the pollen/nectar upon which the brood subsists.
Woodpeckers eat carpenter bees, as do various species of birds, such as shrikes and bee-eaters as well as some mammals such as ratels.