"I am working to improve the way we train and manage pandas in captivity so that we can help save this iconic and endangered species."

Ayala was excited the first time he saw the pandas up close at the base, but when he thought about how he was going to train the pandas, he became worried.

"Pandas can be 150 kilograms. The first time I fed a panda, I was very nervous because its mouth was so big and its jaws are so powerful. It could take your hand right off," he says.

The first panda Ayala trained for an ultrasound was Jing Jing. She is very famous because she was chosen as the living mascot for the 2008 Beijing Olympics. She symbolized the black Olympic ring and was one of the five Fuwa mascots who represented different endangered species of China.

Based on his past experience in animal training, he knew the first step was to gain her trust and establish a working routine with her.

"All animals respond differently to training and interaction with people. However, the principles of positive reinforcement, which we use to train animals, are the same. You always want to reward 'good' behaviors and encourage the animal to feel positive about the work you are doing," Ayala says.

He decided to begin by observing panda habits.

"Pandas eat mostly bamboo. But they really love sweet things such as honey and apples. So we use this as a treat for training," Ayala says.

Jing Jing is in her breeding stage when she has a chance to conceive. Because of this, it is essential to monitor her for pregnancy. A panda can behave as if she is pregnant and the hormones from her urine and feces can indicate she is pregnant. However pandas have the ability to fake pregnancy and not give birth. An ultra-sound is the only way to tell for certain whether a panda is pregnant, so it is important to train her to undergo the examination voluntarily. Before a veterinarian can perform an ultrasound on Jing Jing, Ayala had to teach her to lie down and rollover.

To position the panda, he trained her to touch her nose to the tip of a pole. Together to lie down, he put the tip very low on the ground so she had to lie on the floor.

When Jing Jing acted as he wanted her to, Ayala would reward her with a slice of apple and a scratch on the back.

After working with Jing Jing for six months, Ayala found her restless one day and thought she might be pregnant. He managed to make her lie down and roll over before an examination.

"However, a baby could not be seen. Jing Jing has never been pregnant. This is the perfect example of the pseudo or 'false' panda pregnancy," Ayala says.

After Jing Jing, Ayala used the same method to train three other pandas to have the ultrasound examination.

Other panda experts in the base say Ayala's job is very important and essential to their work in preparing the animals to be released into the wild.