These two Sumatran Tiger cubs were recently born at the San Diego Zoo Safari Park. This is the 24th and 25th births of this critically endangered species for the Zoo. 

The cubs are still too small to leave their den and are being attentively raised by their experienced mother, Delta. On Thursday, keepers gave Mom a short break to stretch her legs and get a little sun while they took the opportunity to socialize with the cubs as shown in the video below. The 10- and 11-pound cubs are being desensitized to human touch in anticipation of vaccines and other necessary veterinary care.They are only just beginning to move around the den on their own paws. Keepers expect them to be more agile and ready to explore the outdoors in July.

Only about 400 Sumatran tigers are left worldwide. They're the smallest of the tiger species, but once grown, males can weigh up to 220 lbs. The San Diego Zoo is home to six Sumatran tigers and is fund-raising to build a new, forested tiger haven that will offer up-close views and highlight conservation efforts

Photo Credit: San Diego Zoo