Sydney  - The family of a 5-year-old who went missing Sunday in far-north Queensland while out with his 7-year-old brother fear he may have been taken by a crocodile.

Police said the boy jumped into the Daintree River to rescue his dog, but disappeared under the water.

"The 7-year-old suddenly saw the 5-year-old disappear," Inspector Dave Ellis said. "A very short time later there was a crocodile also seen."

The Daintree River is home to many crocodiles. dpa