Speed Reads

It wasn't all bad

After 16 years of infertility, southern white rhino gives birth to first calf

Researchers at the San Diego Zoo Safari Park believe a change in diet could be behind a southern white rhino baby boom.

On April 30, a southern white rhino named Kiazi gave birth to her first calf, following 16 years of regular breeding. After nine years of study, scientists at the San Diego Zoo Institute of Conservation Research discovered that southern white rhinos born in zoos are often infertile, and that's likely due to compounds, called phytoestrogens, that are found in the soy and alfalfa they are fed. In 2014, the zoo changed their diets, and two years later, two female southern white rhinos, which are a near-threatened species, were pregnant.

"The birth of Kiazi's calf gives us a great deal of hope that by feeding low phytoestrogens at our institution and others, we can once again have a healthy, self-sustaining captive southern white rhinoceros population," said Dr. Christoper Tubbs, senior scientist in reproductive sciences at the San Diego Zoo Institute for Conservation Research. The calf was born weighing 125 pounds, and by the time she is 3 years old, she could weigh between 4,000 and 5,000 pounds. Catherine Garcia