Australian “Crocodile Hunter” and Discovery Networks personality Steve Irwin was killed Monday by a stingray while filming off Queensland’s Great Barrier Reef.

The 44-year-old was shooting a segment for an upcoming Animal Planet documentary called “Ocean’s Deadliest” when he swam too close to a stingray. The animal’s barbed stinger pierced his heart, according to media reports. Boat crew members called emergency services and administered CPR as they rushed Mr. Irwin to the nearest medical facility, where he was pronounced dead.

Mr. Irwin was best known stateside for Discovery Networks series and specials, beginning with 1992’s “The Crocodile Hunter.” His khaki uniform, exuberant style and use of the catch-phrase “Crikey!” helped make the colorful Mr. Irwin a household name.

But for viewers, Mr. Irwin’s most captivating trait was his willingness to take risks. Until Mr. Irwin, most nature documentary hosts were observational. But Mr. Irwin helped pioneer a new gonzo style. He would not only find deadly animals such as crocodiles and snakes, but pull them into the open and demonstrate their traits and reflexes. He would tease and wrestle the creatures, prompting them to strike — with Mr. Irwin staying just out of reach.

Occasionally critics would say Mr. Irwin took too many chances. In 2004, he held his infant son in one arm while feeding crocodiles with another, promoting public outrage.

Irwin owned and was a star attraction at the Australia Zoo. In addition to his television documentaries and talk show appearances, Mr. Irwin also appeared in the theatrical films “Dr. Dolittle 2” and “The Crocodile Hunters: Collision Course.”

Mr. Irwin is survived by his American-born wife Terri, their daughter, Bindi Sue, and son, Bob.