Dens of two female snow leopards with cubs have been located in Mongolia and the first known video of a mother and her cubs has been shot, conservationists say. Scientists from the Snow Leopard Trust and Panthera, a wild cat conservation organization based in New York, located the dens of the secretive and elusive cats in the country\'s Tost Mountains. \"We have spent years trying to determine when and where snow leopards give birth, the size of their litters, and the chances a cub has of surviving into adulthood,\" Panthera\'s Tom McCarthy said in a release. \"This is one of those exceptional moments in conservation where after years of effort, we get a rare glimpse into the life of an animal that needs our help in surviving in today\'s world.\" Using a camera mounted on an extended pole, Panthera researcher Orjan Johanssen made a short video of one female and her cub bedded down in one of the dens. Researchers entered the two dens -- while the mothers were away hunting -- to weigh, measure and photograph the cubs, two of which were fitted with tiny microchip ID tags under their skin for future identification. The utmost care was taken in handling the animals to ensure they were not endangered, they said. The researchers monitored the mothers\' locations to ensure that they returned to their dens and their cubs, which they successfully did without apparently sensing the intrusion.