The Tigans are tall, strong, and quick. Often referred to as serious-minded and refined, the Tigans are well-muscled and covered with short, sleek fur, giving them a seal-like appearance. They have bristly whiskers on their noses, sharp teeth, and long tails. They are excellent swimmers. Taller and more slender than humans, they have long bodies and short limbs. Tigans are equally comfortable walking upright or on all-fours. Each hand or foot is equipped with retractable claws for climbing or defense. The Tigan race is believed to be descended from a predatory aquatic mammal which lived in riverside burrows, but later dug deeper into the ground and farther from water. Each burrow is inhabited by all members of a Tigan family; collectively, they are called a sept. Each sept is distinguished by its lone fertile male breeder. This male, along with the one fertile female, give birth to the sept's members. All male Tigans are born fertile; one of every hundred Tigans born is a male. Of 500 female Tigans, only one will be fertile. These fertile members of the sept, while revered for their fertility, are forced to remain in the burrows. The sterile females run the day-to-day activities of the sept. Non-familial groupings of Tigans, such as the government, are called dens. Each den is made up of sterile females. The Tigans have learned that dealing with other aliens, especially humans, is dangerous. Thus, only specially-trained females ever leave their burrows and contact the outside world. These females learn Basic in addition to the normal conversational Tigan tongue. All Tigans can also speak a modified language of sounds that is used in their burrows. Its pure sounds are not affected by echoes or other auditory anomalies caused by the burrows.