Henry the world's oldest known crocodile is celebrating his 124th birthday at a conservation center in South Africa today (Dec. 16).

The Nile crocodile (Crocodylus niloticus) has lived at the Crocworld Conservation Centre in Scottburgh, South Africa since 1985. He was originally captured in the Okavango Delta in Botswana in 1903.

Henry, now a vigorous senior resident at the Crocworld Conservation Center, is said to have fathered over 10,000 offspring with numerous partners since he arrived there almost 40 years ago.

While his exact birthday is unknown, Crocworld representatives estimate he was born around 1900 and celebrate his birthday on Dec. 16 each year.

"He's clearly old," Steven Austad, a biologist studying animal aging at the University of Alabama, told Live Science. "Whether he's 100 or 130, we don't really know. An age of 124 is not inconceivable for a crocodile."