Ben Du Toit, a paramedic who arrived on the scene, told reporters the child had been dragged several yards away from the van after midnight while the family was sleeping. The father fought off several other dingoes besides the one that grabbed his son, Mr. Du Toit said.

Fraser Island gets about 400,000 visitors per year and is well known for its roughly 200 dingoes, which roam free on most of the island. Human-dingo interactions are relatively rare, and attacks on humans are even rarer.

But it was the third dingo attack this year on the island, where officials train visitors on how to stay safe from the dogs. A 6-year-old boy was bitten on the legs in January, and the following month a 9-year-old boy and his mother were both bitten. The latter attack led to the euthanization of two dingoes.

A dingo was also euthanized in July after biting a woman and a child.

When dingoes do attack humans, children are often the targets “because their size does not intimidate a dingo as much as an adult person,” according to the Queensland Department of Environment and Science.

It was not known why the dingo attacked the toddler on Friday.

Visitors to Fraser Island are encouraged never to feed the dingoes, which have a diverse range of prey, including fish, small reptiles, rodents, bandicoots, wallabies and kangaroos.