As the days get shorter and cooler, we inevitably get more questions about the elephants’ ability to deal with the cold, and how we manage them through the long cold winter months here in DC. In fact, they handle the cold fairly well, though they have some issues walking on ice and snow. I know how well elephants manage cold weather from watching the three I have worked with, but also by looking at the natural history and distribution of elephants around the globe. I have also learned a lot from researchers studying mammalian physiology.
Let’s start with the last: the general rule of thumb is that large animals lose heat more slowly than small animals because of their ratio of body mass to surface area changes. A mouse has a much larger surface-area to body mass ratio than an elephant does. A mouse has much more surface area, which can either allow body heat to escape or absorb heat from other sources. An elephant, when moving from a warm barn to a cold habitat takes a lot longer to lose its body heat and feel the cold than a mouse would. The catch is that if the elephant’s body temperature does drop and they start to feel cold, it takes a correspondingly long time for them to warm up again.
|Kandula enjoying a snow day. Photo courtesy of Courtney Janney, NZP.|
At the Smithsonian’s National Zoo, our elephants have access to the outside most of the year, and even overnight, in the winter down to 28 degrees. But they also always have the choice to retreat to the barn, which we keep at a cozy 65 degrees Fahrenheit. The barn is this warm largely for the sake of grand dame Ambika, 63. If it was just Shanthi and Kandula, we could go as low as 55. We keep the elephants inside every day after their morning baths until they are dry if the outdoor temperature is below 55.
Another factor that determines whether we give the elephants outdoor access is precipitation. The bottom line is that elephants don’t make good ice skaters. While they may enjoy the first snow of the year, like for some of us, the 20 inch accumulation we get in February can be a little annoying. Elephants like to have a sure footing. They avoid areas where there is ice on the ground from rain or from elephant-compressed snow. Unfortunately, they will traverse ice carefully if they think they’ll find food on the other side, but then they’ll be very hesitant to cross it again to get back to the barn. We spend a lot of time in the winter months inspecting the yards and making sure that there are no hidden patches of ice more than a yard in diameter (a size set by us), and that there are cleared pathways through the yards so that the elephants never feel like they are stuck.
Several years ago we took the time to look back over our records and determined that on an average the elephants are locked inside (without outside access) for a total of two weeks each year. This may have changed in the last two years with the blizzards of 2010 and 2011 but with the new barn’s more efficient HVAC system working so well, we do not expect to have that number of lock-in days in the years to come. Also, “lock-in” days are not as bad as they may sound. Elephant lock-in days equal super enrichment days. We spend all day entertaining the elephants. Like parents with kids stuck inside, keepers end up exhausted but we have happy, content dependants scattered around the barn playing with new toys.
In the wild, scientists study how elephants adapt to colder temperatures. Asian elephants living in areas of Nepal and Northeastern India regularly experience near freezing temperatures at night in the Himalayas. African elephants live at the southern tip of Africa and at upper elevations on the slopes of Mount Kenya and Kilimanjaro in Tanzania.
Having been lucky enough to visit the Aberdere Range and Mount Kenya several years ago in April, I know that it can get quite cold at night, and there were elephants all around us. We have a similar set up in ECC or Elephant Community Center here at the Zoo. Elephants living in areas where it is cold because of high elevations can descend to lower elevations if they get too cold. Here they can move indoors to warm up and still be on a substrate similar to what they would walk on in the wild.
We will have had two important milestones this year. On November 25, our boy Kandula turned ten. We celebrated in-house by giving him a birthday cake made from elephant-approved ingredients. And there were edible (for an elephant) banners that he ripped up like wrapping paper as he made his way to the cake. We’re also celebrating a significant anniversary for Ambika. She arrived at the Zoo 50 year ago!
There have been a couple of neat additions to the Phase II construction. Last week the new skylights were installed. These are the same as the ones in Phase I that are designed to automatically open and close based on different conditions to optimize heating and cooling and to make the building more energy efficient.
We saved the original 1937 brass inlaid floor medallions showing the different animals that lived in the house for the new public area. These were designed by Charles R. Knight who also designed the cast aluminum plaques that were above the enclosures and the relief murals that are located above each set of entrance doors. Knight was a very well known and influential artist in the late 19th and early 20th century who created many works of art depicting dinosaurs and other prehistoric animals. His pieces can be seen in many natural history museums around the country.
Questions and Comments?
I now have an account where people can email questions about the elephants at the Zoo and elsewhere. I will always try to answer the questions as accurately as I can but I can’t guarantee it will be in the form of an email to the sender. I may decide the best way to answer is to post my reply in an Elephant Diary.