Once released into the wild, numbats (Myrmecobius fasciatus) that were bred at Perth Zoo struggle to survive. Some become victims of predators, while others die due to various causes such as starvation, a study says.

According to a study published in the Australian Journal of Zoology, the number of numbats in South Australia's Yookamurra sanctuary and western New South Wales' Scotia sanctuary is gradually increasing. However, while the Australian Wildlife Conservacy's sanctuaries are fenced and are protected from foxes and cats, the endangered species still face a high mortality rate.

'The trouble is once they're released the numbats struggle to identify predators [at Yookamurra and Scotia],' Australian Wildlife Conservancy researcher Matt Hayward told the Science Network. At least 80 percent of the released marsupials have reportedly died or have their tracking collars fail. Four out of the 30 numbats released became victims of raptors. Another nine also died because of starvation and other reasons.

Before releasing the species, Perth Zoo trained young numbats to recognise the calls of various predators and to flee and hide in burrows once they hear them. Despite that, Hayward said that the different sounds or calls of local raptor birds might not have been integrated in their training programme, making the numbats fail to know that it is time to hide.

Parents of young numbats also fail to train their young. 'Often the young are just left back at the den site and the adults go off and forage,' Hayward said. Because of this, they receive only a small amount of time to learn effective strategies to avoid predators.

The numbat, also known as the banded anteater, is classified as endangered by the International Union for Conservation of Nature in their Red List of Threatened Species. Under Australian law, the species is also listed as threatened.