Andear Bear Update: July 2011
By Keeper Karen Abbott
The National Zoo’s two Andean bear cubs, Chaska and Bernardo, are now 18 months old and continue to thrive. 
Read the news about their birth.
Bernardo weighs in at 77 kilograms (170 pounds) and Chaska at 49 kilograms (108 pounds). The size difference between male and female Andean bears expresses itself early. Both cubs are still with their mother and are still nursing. Some days I have observed them nurse as many as four times. They vocalize while they nurse, making a sort of humming sound. Most research suggests that bear cubs remain with their mothers for quite a long period—estimates range from 12 to 24 months. It is thought that because, they are omnivores, they have to learn extensive foraging skills from their mother.
In addition to their obvious size difference, Chaska and Bernardo have developed very distinctive personalities. Chaska is inquisitive, the first to inspect anything new. She is the first to try a new toy or a new food. She is the first to sort through a challenge and come up with a solution. I have seen her push two toys to a certain location and then stack them to make a ladder to reach something she wanted.
She will grab the food she wants and go off to eat it by herself to make sure that she actually gets to keep it. Bernardo dominates the food selection process because of the advantage his size gives him.
Bernardo, on the other hand, is very cautious about new things, letting either Chaska or his mother, Billie Jean, check them out first. Once they have established everything is all right, Bernardo joins in with gusto. One of his favorite things is a large stock tank filled with water that he can stand in and play with his sister.
He is incredibly strong and both he and his sister enjoy throwing things around their dens inside as well as the yard outside. Outside, the throwing is geared toward getting the object closer to the moat. Their last throw lands the object in the moat and concludes their game. Last weekend they managed to empty and throw a 100-gallon stock tank I had dragged in to the yard into the moat. It was a collaborative effort with Billie Jean also participating in the endeavor.
Now that summer has hit D.C., their behavior patterns have changed a bit. During the heat of the day they are difficult to see, a fact that is not surprising as their black coats absorb the heat. Our Andean bears are offered indoor access when the temperature is above 85 degrees. During the warmest part of the day they seem to prefer lying on their backs on the cool concrete.
If it is below 85 degrees, they are on exhibit on weekends from 10 a.m. until 2 p.m. Early in the day is when they seem to do most of their climbing. It looks as if Chaska might be trying out her nesting skills in the first large tree. If you look at the second tree, you will see where Bernardo has stripped a large amount of bark of it and chewed on it, a natural behavior for an Andean bear.
Since most data suggest that this species is solitary in the wild, except for mating times, their father, Nikki is kept in the next exhibit over. He does show some interest in Billie Jean, Bernardo, and Chaska. If you are lucky enough to be there at the right time you might hear him vocalizing at the group in the next yard. The best time to see Nikki is also is early in the day, where he often can be found asleep on the wall.
