The genus name was coined after specimens collected in the late nineteenth century, when the eagle was reported to prey on monkeys. The English name monkey-eating eagle followed and was official until 1978, when it was changed to Philippine eagle.
Diet studies at nests give a different picture. On Mindanao the Philippine flying lemur, a gliding colugo rather than a true lemur, is the dominant prey item, supplemented by civets, rodents, snakes, monitor lizards and birds including other raptors. Macaques are taken but do not dominate. Prey composition also differs between islands, which is part of why early accounts were misleading.
The species remains among the rarest large eagles. Population estimates are in the low hundreds of pairs, forest loss is the main pressure, and shooting still occurs. Because pairs need large tracts of mature forest and raise one chick at long intervals, replacement is slow and any adult loss matters.