World's Oldest White Rhino, a 'Good Giant' Who Played With Hippos, Dies at 54

The world's oldest captive white rhino has died at the age of 54, according to the Italian zoo he was kept.

The rhino, Toby—also known affectionately by zoo staff as "Grandpa Toby"—passed away on October 6 at the Parco Natura Viva zoo in Veneto, northern Italy.

He was accompanied by his keeper as well as vets and the zoo's CEO, Cesare Avesani Zaborra, who described the animal as a "good giant" and his death as "profoundly sad."

In a press release the zoo described how Toby was essentially an acquired grandfather to a group of little hippos, whom he allowed to play with his tail and horn.

The hippos were born and raised alongside the white rhino and shared a section of the zoo with him.

"And so, another piece of 20th century biodiversity goes away while the race against extinction…is increasingly played out in zoological parks," said the zoo, translated from Italian.

In a statement to AFP news agency, a zoo spokeswoman said white rhinos normally live up to 40 years old in captivity, highlighting Toby's longevity.

White rhinos, the world's second-largest land mammal, have a relatively small population. There are thought to be about 18,000 left in the wild, according to the World Wildlife Fund.

There are two subspecies: The northern and southern white rhino. Of the northern type, there were only two left as of March 2018—and both were female. They are based at a conservancy in Kenya.

Toby was a southern white rhino, a subspecies that was thought to be extinct until a small population of less than 100 was found in South Africa in 1895. Since then, conservation efforts have brought their numbers up and they are currently the only one of five rhino species not to be classified as endangered.

Yet in the last decade alone, poachers have killed nearly 10,000 rhinos across Africa in order to sell their horns on the black market, the International Rhino Foundation states.

White rhinos can grow to a height of around six feet and weigh nearly 8,000 pounds.

According to Parco Natura Viva, Toby is due to be sent to Italy's Trento Science Museum (MuSe) so that he can "continue to give a face and a form to the thousands of rhinos that are slaughtered every year."

The zoo is now left with just one white rhino, a 39-year-old named Benno, France24/AFP reports. Toby's life partner, a female called Sugar, died nearly a decade ago in 2012.