Thorough examinations confirmed that three newborn Sumatran tiger cubs born at the San Francisco Zoo are in good health.

The cubs, all male, were given a clean bill of health, with zoo veterinarians giving praise to their mother, 230-pound Leanne, for keeping the newborns well fed.

The mother is doing and "excellent" job, despite being a first-timer, according to Jacqueline Jeneck, the chief veterinarian.

According to the San Francisco Chronicle, the cubs were dangling on an average of 30 to 40 percent mortality rate for Sumatran babies - a number that farther dropped with those of first-time mothers.

Upon finally entering the enclosure after giving the mother time to bond with her three cubs, veterinarians examined the newborn babies, and determined that two were at 4.2 pounds, and the other at 4.8 pounds.

Zoo officials, upon first learning of the births, primarily thought Leanne had produced only one cub. They then discovered the two other cubs when the mother got up to have a drink of water.

Leanne, along with her mate George, are both part of the zoo's breeding program for their endangered species, according to the UPI.