Quick Answer. There are 50 to 60 million kangaroos living on the Australian continent. There are 48 kangaroo species, and the current population is the highest on record, as of 2014. The kangaroo is the most common large wild mammal on Earth because of its growing numbers. There are twice as many kangaroos in Australia as there are sheep. There are nearly three times more kangaroos than cows in Australia. The kangaroo eats grass just like cattle and sheep, so the grassland consumption of kangaroo populations is monitored closely.