This is Delta’s second litter (see Kym’s blog, Tiger Cubs Find a New Home), and she is proving to be a seasoned professional at mothering. After careful behavioral observations by her keepers, combined with hormone analysis by our researchers, Delta was bred to male Utan on July 31 and August 1. The average gestation for a Sumatran tiger is 104 days and Delta stayed close to this expected timeline, giving birth on day 105. For several days leading up to the birth, Delta was kept inside the tiger house, and keepers stayed with her 24 hours a day, monitoring her for any signs of labor via a camera system so as not to disturb her. She was provided with a den box filled with soft bedding hay as well as some extra heaters for warmth. Delta decided our efforts were satisfactory and chose to have her cubs in the box as we had hoped.
Sumatran tiger cubs are very small at birth, weighing only 2 to 3 pounds (0.9 to 1.3 kilograms) and their eyes remain closed for the first 7 to 10 days. We monitored the cubs and Delta for the first few days without interference. This allowed Delta to become comfortable with the cubs and regain her appetite. For the first several days, Delta was so occupied with being a mother that she did not leave the cubs alone while she ate. On November 19, the keepers separated Delta from her cubs for the first time, and we were able to physically meet the cubs. While Delta was eating in an adjacent room, we were able to sex the cubs and get weights on them all. The walls on the den box are about 12 inches (30 centimeters) high, and for the first several weeks sufficed as a barrier to the cubs, but they have since found their way out!
At one month of age, all of the cubs are mobile and climb freely in and out of the den box. Harimau Kayu is the most agile of the cubs and the most adventurous! He was the first out of the den and has explored the entire bedroom on increasingly steady legs. Damai has definitely taken after her mother: from one week of age she has had a ferocious temperament. She is definitely a little tiger! Kucing is our little rock: he stays close to his mom and his siblings, never straying too far on his own. They are growing at a steady rate of about 1.5 pounds (0.6 kilograms) per week; Damai is the smallest at 10.1 pounds (4.59 kilograms), followed by Kucing at 10.5 pounds (4.77 kilograms) and Harimau Kayu, the largest, at 10.6 pounds (4.83 kilograms).
The cubs are still far too small to go out into the exhibit and will remain in the safety and comfort of the house for the next couple of months. I will be sure to keep you posted on their progress!
Kym Nelson is a senior keeper at the Wild Animal Park.
Read Kym’s previous blog, A Strange New World for Kamau the Lion.