How Do Cassowaries Work?

These flightless birds are the second heaviest birds in the world -- they can grow as large as an adult human. Learn about them in this episode of BrainStuff, based on this article: https://animals.howstuffworks.com/birds/cassowary.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff, a production of I Heart Radio,
Hey brain Stuff Lauren Vogelbaum here. The cassowary is a massive,
flightless bird that's been called the most dangerous bird in
the world, the reason being that it could seriously injure
or kill a human or pet in an instant with
its deadly claws. And they're very quick. They are powerful

(00:25):
legs let them run at about thirty miles an hour
more fifty kilometers an hour through dense forest underbrush. In Florida.
Cassowaries are listed as Class two animals, along with alligators
and wildcats due to the risk they pose, which means
anyone who wishes to own one must pass numerous tests
and get a special permit from local authorities. Alike their

(00:48):
emu cousins, cassowaries are rattites, or birds that have flat
breastbones and are unable to fly, and they boast bristly feathers,
a vivid blue face, two red bottles hanging from their neck,
and a prominent helmet or cast atop their head. Three
different species of cassuaries are native to tropical forests of

(01:09):
Australia and Southeast Asia, although size varies across those three species,
the Southern, Northern, and dwarf. They can stand up to
six and a half feet tall that's two meters, and
weigh as much as a hundred and thirty pounds or
sixty kilos. If you happen to be familiar with swans,
this is the equivalent of about six swans, presumably stacked

(01:31):
in a cassowary shaped trench coat. They cannot fly, but
they do have those muscular legs, and that brings us
to the hazardous point of these birds their inner claw.
For the article this episode is based on, has to
Fork spoke with Rick Schwartz, a global ambassador for California's

(01:51):
San Diego Zoo, which currently houses several Southern cassuaries in
its Safari park. He explained the claw on the inner
of each foot is what is so impressive between the
three species. That claw is very sharp and can range
from three to five inches or seven to twelve centimeters long,
and the cassowary will use these sharp claws and their

(02:12):
powerful kick to defend themselves. It's often stated that they
can eviscerate a human in a single kit, though there
is no record of this happening. They also have a
lot of weight to throw around. A Swart said. Cassowaries
are the heaviest bird in Australia and the southern cassuary
is the second heaviest in the world. The world's heaviest

(02:33):
bird is the ostrich. With that in mind, they also
have very small wings. When stretched out, their wings extend
less than a foot or point three meters from their body.
A cassowary has dense, black feathers that are long and thin,
compared with the wide and shapely feathers of a flighted bird.
A Schwartz said, from a distance, some people even say

(02:55):
the feathers of the cassowary look more like hair. The
cassowaries feathers are not suitable for flight, but they work
very well for a ground dwelling bird living in a
forest ecosystem. The longer, thinner feathers helped direct water away
from the body and also protect the bird's body from
low branches, but sharp twigs and thorns. Meanwhile, they are

(03:16):
prominent facial features. That cask and those wattles are something
of a mystery. Evolutionarily speaking, the cask or that helmet
is made of keratin, the same protein that birds feathers, nails,
and beaks are made of and our hair and nails
too for that matter. Schwartz explained. The outer covering is
thick and hard, but the inside is very porous. The

(03:38):
purpose of the cask is not completely understood, but several
theories exist, including that it can help amplify vocalizations, serve
as head protection as the bird pushes headfirst through dense forest,
or it may be another way for the birds to
display age and vitality. As for those bright red wattles,
Schwartz explained, of the three species of castaways, only the

(04:00):
northern and southern cassuaries have wattles. It's thought that they
can help communicate the bird's current demeanor, indicate an individual
bird's vitality to other cassawaries, or give other cues and
communications only known by cassuaries at this time. For as
fearsome as they may seem, cassuaries are frugivores, meaning they

(04:22):
feed on fruits, which makes them very important to their
surrounding ecosystem. Schwartz explained. As they eat fruit, they walk
around and pass the seeds through their digestive tract. Thus
they're droppings deposit seeds that are surrounded in natural fertilizer,
helping to spread the diversity of plants in their region.
They're considered a keystone species due to their large size.

(04:45):
They're able to spread larger seeds than most other birds,
and those claws help them dig deep in the leaf
litter for fallen fruit that other species might miss. But
don't worry too much about those claws. You'll probably never
encounter a cassuwary in the wild, Schwartz said. What they're
excellent hearing. They will hear you coming long before you

(05:08):
even know they're there, and they will most likely disappear
into the forest to avoid you. However, should you ever
come across one in the wild, it's best to give
them plenty of room and not approach them or try
to feed them. Should you happen to be near one,
though you probably won't hear it, however you might feel it,
and that's because cassuaries call is Schwartz said, a deep,

(05:32):
low frequency, booming sound. It's the lowest known call of
any bird, and it's so low that it borders on
being inaudible to the human ear. If you are nearby
when it does this call, you can feel the vibrations
in your chest. Female cassuaries lay large, beautiful eggs that
typically arranging color from pastel mint to lime green to

(05:54):
vibrant avocado. But after they do they abandon the clutch
and it's up to the male birds to incubate the
eggs and care for the chicks. After they hatch, a
short said, the female returns to her solitary life and
does not participate in incubating the eggs or caring for
the young. This may be a way to allow her
to have several clutches of eggs in one breeding season

(06:15):
with different males, thus diversifying her genetics into the next generation.
But cassawari's population is dwindling. An organization called the International
Union for Conservation of Nature keeps the world's most comprehensive
inventory of the global conservation status of planted animal species,
and they list all three species of cassowary as either

(06:37):
vulnerable or near threatened. Schwartz explained, unlike many species, their
biggest challenges are the loss of habitat due to human
population growth, roads being built causing car strikes, and human
introduced species of animals rating nests. The good news is
that the governments of the country's cassawaries call home are

(06:57):
stepping up their conservation efforts. For example, dogs will kill
young cassowaries. Humans have sometimes hunted the birds for their
meat and stunning feathers. There may be less than a
thousand cassowaries left in the wild, but as Schwartz said,
groups are working to protect and restore cassowaries habitats as

(07:18):
well to create safe passage for these and other rainforest
creatures by a strategic buy back of rainforest properties and
the regeneration of damaged rainforest. Today's episode is based on
the article the cassowary is the World's most dangerous bird
on housetofworks dot com, written by Wendy Bowman. Rain Stuff

(07:40):
is production of iHeart Radio in partnership with how stuff
works dot com, and it's produced by Tyler Playing Before.
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