Last month, a group of Sumatran tigers reportedly killed one man and treed five others in Indonesia after the men accidentally killed a tiger cub in a jungle deer trap. Sumatran tigers are listed as critically endangered: Only 400 to 500 exist in the wild. Damai gave birth to the first cub around 6:15 p.m. and the second around 8:23 p.m. Keepers have been monitoring the cubs and both appear healthy. Damai was only 2 years old when she came to the National Zoo. Male Indian tigers weigh almost twice as much. She will go toe-to-toe with her brother (who is much larger than she) over food and enrichment items. Caption Take a look at some of the animals born at the National Zoo. It’s all a part of growing up—and it certainly hasn’t curbed their appetite. Keepers are hand-raising this female sloth bear, seen March 18, 2014, cub at the National Zoo. We haven’t observed nursing for some time now, so we are almost certain they’re weaned off Damai’s milk. Two rare Sumatran tiger cubs snuggle and nurse with their mother at the Smithsonian’s National Zoo in Washington, D.C. (Smithsonian’s National Zoo) 
 
 Two rare Sumatran tiger cubs snuggle and nurse with their mother at the Smithsonian’s National Zoo in Washington, D.C. (Smithsonian’s National Zoo) 
 
 The keepers knew that their Sumatran tigers had last mated in April. “Tigers are one of the few species of cats that enjoy taking a dip in water,” said Craig Saffoe, curator of Great Cats. Linda Davidson/The Washington Post Buy Photo Wait 1 second to continue. The male cub weighs about 21 pounds and the female weighs about 19 pounds. They are not very good at pouncing on each other yet, but it’s a lot of fun to watch them try! September 5, 2013: Cubs are one month old 
 
 The tiger cubs are one month old today. Veterinarians and keepers report the cubs are healthy, plump and growing quickly. The cubs will not be on exhibit for several months until they have completed a series of four additional health exams, during which they will receive all necessary vaccinations. (Smithsonian's National Zoo) 
 
 “How many people on the planet have seen this kind of thing happen before?” Saffoe said. Look at these pictures of the cubs the keepers got this week. “We knew at that point, ‘Okay, it's alive.’ ” 
 
 1 of 15 Full Screen Autoplay Close Skip Ad × D.C.’s zoo babies View Photos Take a look back at some of the animals born at the National Zoo. The cubs will be examined when the keepers are able to lure the mother outside or into a separate enclosure. These are also the dens she was in for her quarantine period when she first arrived at the Zoo. The cubs will then be given a quick exam in a corridor outside the den. For a few moments, as the mother groomed the cub, the keepers couldn’t tell if it was alive. Not only are our two new Sumatran tiger cubs the cutest cubs in town but they are also a huge conservation success. “It’s taken more than two years of perseverance getting to know Damai and Kavi and letting them get to know each other so that we could reach this celebratory moment,” said Craig Saffoe. Staff trained Damai to participate in ultrasound procedures, which allowed them to confirm her pregnancy on June 21, 2013. This is Damai’s first litter of cubs, sired by the Zoo’s 12-year-old male tiger, Kavi. Tiger fans may be able to watch the newborn tiger cubs at the National Zoo reach every milestone for the next several weeks via live webcams on the Zoo’s website. During the next few weeks the cubs will open their eyes, become more mobile and potentially even start to explore the other dens that Damai can access.
– Endangered Sumatran tigers got two new additions this week: A female named Damai at the National Zoo in DC gave birth to a pair of healthy cubs on Monday. Only about 500 of the tigers exist in the wild, with 65 in zoos in North America, notes the Washington Post. (That includes Damai's mate, Kavi.) The cubs won't be on exhibit for a few months, but you can check them out via a webcam at the zoo's website. "All I can do is smile because the team has realized our goal of producing critically endangered tiger cubs," says a zoo biologist. "Damai came to us as a young tiger herself, so it's really special to see her become a great mom."