The cassowary, a large, flightless bird native to the tropical rainforests of New Guinea and northeastern Australia, has earned a fearsome reputation as the world’s most dangerous avian species. Standing up to six feet tall and weighing up to 160 pounds, it is the second-heaviest bird on Earth, surpassed only by the ostrich. Its striking appearance, featuring brilliant blue and red coloring on a featherless neck and a casque, or helmet, on its head, belies a powerful, solitary creature. Its danger stems from its physical capabilities and highly defensive nature when threatened.
The Anatomy of Danger
The cassowary’s ability to inflict serious injury is tied to the powerful structure of its legs and feet. Its three-toed feet are equipped with sharp claws, but the true threat lies with the dagger-like claw located on the inner toe. This specialized weapon can grow up to five inches long and is straight, sharp, and capable of cutting deep into flesh. The inner claw is the bird’s primary defensive tool, used for inflicting severe injury with a swift kick.
Powering this are immensely strong legs built for both speed and force. Cassowaries can achieve speeds of up to 30 miles per hour and jump nearly seven feet straight up. These powerful legs allow the bird to deliver a forceful, forward-directed kick with enough impact to break bones and cause severe internal damage. The casque, a keratinous growth on its head, is thought to serve multiple functions, including protection from falling debris, a shield in dominance disputes, and an aid in pushing aside leaf litter during foraging.
Triggers and Tactics of Aggression
The cassowary’s aggressive reputation stems from its specific, highly effective tactics when it perceives a threat. Attacks are rarely unprovoked and are typically defensive responses to protect a food source, defend territory, or shield eggs and chicks, which are diligently guarded by the male. Many recorded attacks are also linked to birds accustomed to being fed by humans, leading them to aggressively demand food.
The attack sequence often begins with a warning display, such as hissing, deep booming calls, or erecting the feathers to appear larger. If the threat does not retreat, the cassowary will charge, often leaping into the air and driving its feet forward with a powerful, two-footed kick. The bird aims to strike the opponent with the inner claw, frequently targeting vulnerable areas. The cassowary may also ram opponents using its casque to knock them to the ground, where kicking can be more easily delivered. A study of 221 cassowary attacks found that in 71% of incidents, the bird charged or chased the victim.
Assessing the Actual Risk
Despite its fearsome reputation, the actual risk posed by a cassowary to a cautious human is low. The species is naturally wary and solitary, preferring to avoid human contact deep within the rainforests. Encounters most frequently occur near the edges of their habitat, often where human development has encroached on their territory or where people attempt to feed them.
Historical records show that cassowary-related fatalities are exceedingly rare. A 2003 study of 150 attacks on humans found only one fatality, and a second well-documented death occurred in 2019 when a captive bird attacked its owner who had fallen. While the bird has the physical tools to be lethal, it is not a predatory threat to humans. The best way to avoid an encounter is to maintain distance, never attempt to feed the birds, and slowly back away if one is sighted, as the vast majority of attacks occur when the bird feels cornered or is expecting food.