Spotted hyenas appear much like funny-shaped dogs, with a "skulky" walk like a dog who just ate something off the counter and wants to depart before being punished. They have a smooth, fast lope, and they blend amazingly well into the grass. Their voices carry a long ways and they have very interesting and complex calls to one another, the most famous of which is known as "laughing," because it sounds a lot like human laughter.
Female hyenas are slightly larger than males and are dominant. Females stay in the natal group they were born into and have very strict pecking orders. Males generally leave the pack when mature and hope to join another pack and earn breeding rights. Packs are composed of both males and females, and defend territories. Cubs are very competitive, and cubs are often cannibalized by other members of the pack. Unlike many species, the mother foes not bring back food and regurgitate it for the pups, and the other clan members do not help raise the pups. Perhaps because of this, pups nurse a lot longer than the young of other similar species.
Hyenas scavenge kills of cheetahs, lions, and other predators when they can, but they are also awesome hunters in their own right, and in fact most of their diet comes from live kills. Hyenas have tremendous jaw strength and can crush and chew bones. They eat so much bone that hyena scat is almost a pure, chalky white and looks like hardened, bleached dog poop.
Hyenas compete with lions. If a pack is large enough, they can actually drive lions off a kill. If they don't outnumber lions though, the lions win. Most hyena kills are actually lone kills, but when larger prey is at stake, they hunt in packs. While they look most like dogs, they are actually more closely related to meerkats than to African Wild Dogs. In captivity they are easily tamed.
I was lucky enough to find this hyena in the photo lazing around near a mud patch in the Serengeti. All the hyenas I came across were wallowing in mud or shallow pools to keep cool, and saving their energy. Usually we were able to get within 3-4 feet of them before they took off, but they did flee much before most of the other animals we found, suggesting an abundance of caution. Although they are a much-maligned animal, I found them to be among the most interesting to watch, and you have to admire the niche they have carved for themselves in a very competitive environment.
For information on research and conservation programs, as well as photos and general information about hyenas, visit this page of the African Wildlife Foundation.