information:highlighting
Anthropogenic sources

Flying foxes species are declining or going extinct as a result of several human impacts to their environments, in addition to natural phenomena. Their populations are especially vulnerable to threats because the litter size is usually only individual and females generally only have one litter per year. Even when nearly every female (90%) successfully produces and raises young, if a population's mortality rate exceeds 22% annually, then it will steadily decline.

Invasive species such as the brown tree snake can seriously impact populations; the brown tree snake consumes so many pups that it reduced the recruitment of the Guam population of the Mariana fruit bat to essentially zero.

Many flying fox species are threatened by overhunting. While they have long been a dietary component of indigenous people, expanding human population and more efficient weapons have resulted in population declines, local extinctions, and extinctions. Overhunting is believed to be the primary cause of extinction for the small Mauritian flying fox and the Guam flying fox.

Flying foxes are also threatened with excessive culling due to conflict with farmers. They are shot, beaten to death, or poisoned to reduce their populations. Mortality also occurs via accidental entanglement into netting used to prevent the bats from eating fruit. Culling can dramatically reduce flying fox populations.In Mauritius, over 40,000 Mauritian flying foxes were culled in a two-year period, reducing its population by an estimated 45%. Flying foxes are also killed by electrocution. In one Australian orchard, it is estimated that over 21,000 bats were electrocuted to death in an 8-week period. Farmers construct electrified grids over their fruit trees to kill flying foxes before they can consume their crop. The grids are questionably effective at preventing crop loss, with one farmer who operated such a grid estimating that they still lost 100–120 tonnes (110–130 short tons) of fruit to flying foxes in a year. Some electrocution deaths are also accidental, such as when bats fly into overhead power lines.

Climate change causes flying fox mortality and a source of concern for species persistence. Extreme heat waves in Australia have been responsible for the deaths of more than 30,000 Australian flying foxes from 1994 to 2008. Females and young bats are most susceptible to extreme heat, which affects a population's ability to recover. Flying foxes are threatened by sea level rise associated with climate change, as several taxa are endemic to low-lying atolls.