The weather in Portland, Oregon, is very temperate, with temperatures rarely dipping below freezing in winter or getting too hot in summer. That's good news for the Oregon Zoo's family of Asian elephants, whose range countries tend to be temperate as well. But what about those rare days when it is cold outside?
Like all mammals, Asian elephants heat and cool their bodies through an internal process called thermoregulation. Elephants' large size helps them to maintain fairly constant core body temperatures, and research on elephant thermoregulation indicates their size and metabolic rates combined "result in heat production rates that exceed heat loss rates." That means their bodies hold on to more heat than they lose throughout the day. This extra body heat can be a challenge for some elephants on very hot days, but studies have found it to be "a considerable advantage in cold weather."
All year, Oregon Zoo elephants have the choice to be indoors or outside.
The elephant family at the Oregon Zoo keeps warm in other ways as well. They have nearly 24-hour access to Forest Hall, one of the largest indoor elephant habitats in the world. It's kept at a steady temperature of around 70 degrees â€” warm and comfortable for the elephants 365 days a year, rain or shine. Even on colder days, some individuals choose to leave the heated indoor area and spend more time outdoors, while other members of the herd choose to remain indoors.
When temperatures do drop below freezing, the herd often goes outside for short periods of time. This is especially true on snow days, when the elephants can be seen venturing out to explore, sometimes choosing to spend time under the heated shelters located throughout their habitat. Though they're not usually outside in these temperatures for more than a short time, their care staff says they enjoy these rare snowy experiences.
Elephant Lands was built on the zoo's philosophy that all animals' lives should be filled with choice. The elephants can choose whether to swim in their pool or play in their mud wallow; they can choose to spend time inside or outside. When the temperature drops they can usually be found in Forest Hall, but when they do go outside in the cold their bodies help them to stay warm.