The 6-foot-5-inch kangaroo lunged without warning at 65-year-old Rosemary Neal as she went to check on some horses in a paddock on the property near Mudgee, 160 miles northwest of Sydney on Friday, son Darren Neal said.
The kangaroo "just jumped up and launched straight at her," Darren Neal said. "He hit her once and she just dropped and rolled. My dog heard her screaming and bolted down and chased him off.
"It wasn't for the dog she'd probably be dead."
Rosemary Neal was hospitalized for for deep cuts to her face, hands and back and a concussion, he said.
Kangaroos are widespread across Australia and there are dozens of species in the family, ranging from tiny, 17-ounce potoroos to Red Kangaroos, the world's largest marsupial that can grow past 6 feet tall and weigh more than 200 pounds.
Most species are not considered aggressive toward humans, and attacks are extremely rare. But males fight each other for mates, rearing up on their tails to scratch at the soft belly flesh of their rivals with the powerful legs they more commenly use for their trademark leaps.