Philippine Wildlife · Quiz Article
The Monkey-Eating Eagle That Doesn't Mainly Eat Monkeys
The Philippine eagle's old name made it famous, but field studies tell a different story. Find out what's really on its menu and how this rare raptor lives, then climb the canopy in our 10-question quiz.
For most of the twentieth century, the Philippines' largest eagle was known around the world as the "monkey-eating eagle." The name was dramatic, memorable and easy to sell in nature documentaries. It was also misleading. When researchers sat beneath active nests and logged every animal the adults carried home, monkeys turned out to be a small part of the menu.
3/59
At the first Philippine eagle nest documented on Luzon, researchers recorded 59 prey deliveries. Only 3 were monkeys. Snakes, cloud rats and monitor lizards showed up far more often.
So what does the Philippine eagle really eat, and why did the monkey story stick for so long? This article separates the legend from the field data, introduces one of the world's most remarkable birds of prey, and explains why its future depends on the forests of just a few Philippine islands.
A name that oversold the monkeys
The bird entered Western science in 1896. The English explorer John Whitehead was collecting specimens on the island of Samar, and the first eagle specimen was obtained there by his team. The ornithologist William Robert Ogilvie-Grant described the species that same year, giving it the scientific name Pithecophaga jefferyi.
The genus name comes from Greek: pithekos means "ape" or "monkey," and phagos means "eater." The species name honors Jeffery Whitehead, the explorer's father. Early accounts reported that the eagle hunted monkeys, and the English name "monkey-eating eagle" followed naturally.
The label wasn't invented from nothing. Philippine eagles do catch long-tailed macaques, and a big monkey is an impressive meal. The trouble is that a dramatic occasional prey item became the bird's whole identity, while the animals it catches most often were left out of the story.
A name describes what people noticed first. A diet study describes what actually happened, one prey delivery at a time.
Meet the eagle: field profile
The Philippine eagle is one of the largest and most powerful eagles on Earth. In length and wing area it ranks among the very biggest. It has a shaggy crest of long brown feathers, a cream-white face and underside, pale blue-gray eyes, and a massive, deeply arched blue-gray bill built for tearing.
Specimen label · Accipitridae
Pithecophaga jefferyi
Ogilvie-Grant, 1896
- Common name
- Philippine eagle (formerly "monkey-eating eagle")
- Local names
- Haribon, Banog
- First collected
- Samar, 1896
- Range
- Luzon, Samar, Leyte and Mindanao
- Habitat
- Old-growth and mature tropical forest, often on steep slopes
86–102 cmbody length, bill to tail
1.8–2.2 mwingspan
4–8 kgweight; females are larger
~392estimated breeding pairs (2023)
1 eggusually, about every 2 years
CRCritically Endangered (IUCN)
The bird is found only in the Philippines, and only on four major islands: eastern Luzon, Samar, Leyte and Mindanao, which holds the largest population. It does not live on Palawan, Cebu or the other islands of the Visayas. DNA studies suggest that its closest living relatives are the snake eagles, a link that makes more sense once you see how many snakes turn up in its diet.
The eagle's menu, by the numbers
Prey delivered to a Luzon nest, grouped by animal type (Abaño, Salvador & Ibañez, 2016).
Sample: 59 prey items, 91.4 kg of identified prey biomass.
Unidentified items have no weight estimate, so they are left out of the weight view.
Two lessons jump out. First, by count, monkeys are a small slice: 3 of 59 items, or about 5%. Snakes alone made up a quarter of all deliveries. Second, by weight, monkeys matter more. A long-tailed macaque is heavy, so those three catches supplied about a fifth of the food by mass. Both views are true, and together they show why scientists measure diets in more than one way.
So is the old name wrong?Not entirely. It's misleading. "Monkey-eating" suggests monkeys are the main food, when the data point to a flexible hunter of many forest animals. That is why scientists and conservationists prefer "Philippine eagle."
Different islands, different menus
What an eagle eats depends on what lives in its forest. The Philippines' islands have different wildlife, so the eagle's diet changes from one population to the next.
Mindanao
Largest population- Philippine flying lemurs (colugos), gliding mammals that are often reported as the main prey
- Palm civets and other civets
- Monkeys, snakes, flying squirrels, birds and other medium-sized animals
Luzon
No flying lemurs live here- Northern Luzon giant cloud rats, large tree-dwelling rodents
- Snakes, including rat snakes
- Monitor lizards
- Birds, civets, fruit bats and some macaques
A 2003 study of a breeding pair on Mount Sinaka in central Mindanao, published in The Wilson Bulletin, found that civets and flying lemurs made up the bulk of the prey brought to the nest. Across its range, the pattern is the same: the Philippine eagle is an opportunistic predator of medium-sized forest animals, not a monkey specialist.
How a forest eagle hunts
Open-country eagles often soar high and scan wide landscapes. The Philippine eagle lives in dense forest, so it relies on patience, surprise and short, powerful attacks. Its broad, relatively short wings and long tail help it steer between trunks and branches.
Perch & watch
It sits quietly on a branch in the middle or upper canopy, watching for movement.
Drop & move
If nothing appears, it glides to a lower perch and repeats, working its way through the forest.
Strike
Prey is seized with huge, strong talons, often from a tree trunk or branch.
Pairs have also been observed hunting together. One eagle may draw the attention of a group of monkeys while its partner swoops in from another direction, a reminder that monkeys are on the menu, even if they aren't the main course.
One chick every two years
Philippine eagles are thought to pair for life, and a pair needs a large territory. Their breeding is extremely slow. A pair usually raises a single chick in a full cycle that lasts about two years, and they breed only once in that time.
A two-year family timeline
Approximate stages, drawn to scale across 24 months.
Month 06121824
CourtshipNest building and display flights.
IncubationUsually one egg, about 58–68 days.
NestlingThe chick fledges at about 4–5 months.
DependenceParents keep feeding it, around 20 months of care in total.
Females reach breeding age at about five years and males at about seven. One chick every two years means that each adult lost to a bullet, a trap or a power line takes years to replace, which is why every individual counts.
From "monkey-eater" to national bird
In 1978, a presidential proclamation under Ferdinand Marcos officially changed the bird's name from "monkey-eating eagle" to "Philippine eagle." The new name was more accurate and tied the species to the country where it lives.
On July 4, 1995, President Fidel V. Ramos signed Proclamation No. 615, declaring the Philippine eagle the national bird. Many Filipinos also know it as Haribon, from haring ibon, "king of birds," and in parts of the country as Banog.
Seeing one responsiblyThe Philippine Eagle Foundation runs the Philippine Eagle Center in Davao City, where visitors can see eagles in care and learn about conservation. Its captive-breeding program produced its first chick in 1992.
Why it's critically endangered
The Philippine eagle is listed as Critically Endangered on the IUCN Red List, the highest risk category before extinction in the wild. A 2023 study in the journal Animal Conservation, highlighted by the Philippine Eagle Foundation and Mongabay, mapped suitable habitat across the country.
392
The study estimated that the remaining forests could support an average of 392 breeding pairs, with a range of 318–447 pairs. That is higher than some earlier guesses, but still a tiny number for a whole species.
Forest loss
Logging, farming expansion and mining remove the large, old trees eagles need for nesting and hunting.
Shooting & trapping
Eagles are still killed by hunters or caught in traps set for other animals, often illegally.
Huge space needs
A Mindanao pair's home range has been estimated at about 133 km², including roughly 68 km² of forest.
Low genetic diversity
A 2026 genome study led by University of the Philippines scientists found very low genetic diversity, which can make a species less resilient.
The genome research, reported by the Philippine Daily Inquirer, analyzed DNA from 35 eagles cared for by the Philippine Eagle Foundation. It adds a new concern: even if forests are protected, a small and genetically similar population may struggle to adapt to disease or environmental change.
Protection & how to help
Under the Philippines' Wildlife Resources Conservation and Protection Act (Republic Act No. 9147), killing a critically endangered species like the Philippine eagle can bring up to 12 years in prison and fines of up to ₱1 million. Laws alone are not enough, though. Protecting the eagle means protecting whole forests and the communities that live around them.
- Learn and share accurate facts. Correcting the "monkey-eater" myth is a small but real step toward understanding the species.
- Support credible conservation groups, such as the Philippine Eagle Foundation, which work on research, rescue, breeding and community-based forest protection.
- Choose responsible ecotourism. Visit accredited centers and guided programs rather than anyone offering to show you a nest.
- Report wildlife crimes, such as captured or injured eagles, to the Department of Environment and Natural Resources (DENR) or local authorities.
- Back reforestation with native tree species in the eagle's range.
Chapter 10 · Quiz
The Canopy Climb
Ten questions: some "Fact or Fable?", some multiple choice. Every correct answer lifts the eagle one step through the forest, from the forest floor toward open sky. Can you reach the top?
Question 1 of 10
Height: Forest floorFrequently asked questions
Why was it called the monkey-eating eagle?
Early reports said the bird hunted monkeys, and its scientific name, Pithecophaga, means "monkey-eater." It does catch macaques, but diet studies show monkeys are only one of many prey types.
What does the Philippine eagle mainly eat?
It depends on the island. On Mindanao, flying lemurs (colugos) and civets are major prey. On Luzon, where flying lemurs don't live, one nest's prey was dominated by snakes, giant cloud rats and monitor lizards.
How many Philippine eagles are left?
A 2023 habitat-based study estimated about 392 breeding pairs (range 318–447). Population figures are estimates, and the species remains Critically Endangered.
Where can I see a Philippine eagle?
The safest and most responsible way is at the Philippine Eagle Center in Davao City, run by the Philippine Eagle Foundation. Wild nests should never be disturbed.
Is the Philippine eagle the biggest eagle in the world?
It is among the largest. By length and wing area it ranks near the top, while some eagles, such as the harpy eagle and Steller's sea eagle, can be heavier.
Sources & further reading
- Abaño, T.R.C., Salvador, D.J.I. & Ibañez, J.C. (2016). "First nesting record of Philippine Eagle Pithecophaga jefferyi from Luzon," Forktail 32.
- Ibañez, J.C. et al. (2003). "Notes on the breeding behavior of a Philippine Eagle pair at Mount Sinaka, Central Mindanao," The Wilson Bulletin 115(3).
- Philippine Eagle Foundation, "Priority conservation areas and global population estimate for the Philippine Eagle" (on the 2023 Animal Conservation study).
- Mongabay, "New map boosts Philippine eagle population estimate but highlights threats" (March 2023).
- Philippine Daily Inquirer, "Philippine eagle faces higher risk of extinction, study finds" (June 2026).
- EDGE of Existence, Survival Blueprint for the Philippine Eagle (PDF), including home-range figures.
- Republic Act No. 9147, Wildlife Resources Conservation and Protection Act (summary).
- Wikipedia, "Philippine eagle", a general overview with references.