In bear years, that means he is now officially a teenager, since pandas becomes sexually mature at age 5 or 6, according to the Zoo.
It remains to be seen if Tai Shan starts ignoring the zoo rules, or trashes his pen, or begins taking driver's ed classes, but visitors are expected to check him out in person and on the panda cam.
To honor the birthday boy, the zoo put together an unusual frozen birthday "cake." Made of bamboo, shredded beets and beet juice, the frozen treat took nearly two weeks to make. We're sure he'll devour it much faster than that.
Feel free to head over to the Zoo Web site and send Tai Shan some birthday wishes.