During the 20th century, as humans have encroached more and more on animals' territory, zoos have come to be more than just places to view wild animals.

Ironically, the powerful, dedicated canines profiled in Sled Dogs: An Alaskan Epic are little more than mutts. They are mixed-breed huskies that have endurance.

Ironically, the powerful, dedicated canines profiled in Sled Dogs: An Alaskan Epic are little more than mutts. They are mixed-breed huskies that have endurance.

Ironically, the powerful, dedicated canines profiled in Sled Dogs: An Alaskan Epic are little more than mutts. They are mixed-breed huskies that have endurance.

Ironically, the powerful, dedicated canines profiled in Sled Dogs: An Alaskan Epic are little more than mutts. They are mixed-breed huskies that have endurance.

Ironically, the powerful, dedicated canines profiled in Sled Dogs: An Alaskan Epic are little more than mutts. They are mixed-breed huskies that have endurance.

Though their glory days may be in the past, these hoofed creatures continue to enthrall us, as the NATURE program HORSES demonstrates in sparkling detail.

Though their glory days may be in the past, these hoofed creatures continue to enthrall us, as the NATURE program HORSES demonstrates in sparkling detail.

Though their glory days may be in the past, these hoofed creatures continue to enthrall us, as the NATURE program HORSES demonstrates in sparkling detail.

Though their glory days may be in the past, these hoofed creatures continue to enthrall us, as the NATURE program HORSES demonstrates in sparkling detail.