Why Are Komodo Dragons So Deadly?

We used to think Komodo dragons harbored bacteria in their mouths that made their bites deadly, but it turns out they have venom and iron-tipped teeth to thank. Learn more in this episode of BrainStuff, based on this article: https://animals.howstuffworks.com/animal-facts/komodo-bite.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff,
Lauren bobobam here. The world thought Komodo dragons were mythological
until about nineteen eleven. During World War One, a plane
crashed near Komodo Island and the pilots survived to tell
the world about the animal. He was very lucky to

(00:24):
tell the tale. Komodo dragons live up to their fierce reputation.
They will attack and devour a human being unprovoked, and
they're part of a group of lizards known as monitors.
And they're the biggest lizards in the world. The largest
kimodo ever measured was more than ten feet long that's
three meters, and weighed three hundred and sixty six pounds

(00:45):
that's about one hundred and sixty six kilos. To get
a feel for how powerful this creature is, consider that
when a kimoto weighing just one hundred and twenty pounds
or fifty five kilos in the London Zoo needs a
blood test, it takes two people to hold down its tail.
Compared to the largest on record, the average kimodo is

(01:06):
about eighty percent of the length but only two thirds
of the weight. Many scientists think the record animal may
have eaten a big meal just before weighing in. A
kimodo can consume about eighty percent of its body weight
in just twenty minutes. It can swallow huge pieces at
a time because its skull and jaw are flexible like
a Snake's Komodo prey includes chicken, wild boar, deer, goats,

(01:30):
and animals as big as water buffalo. The komodo is
the only known lizard that will attack prey bigger than itself,
and about one tenth of the komodo diet is other
komodo dragons. There aren't many animals that can survive a
komodo attack. A human and another kimodo are pretty much
the only ones. This endangered animal, down to fewer than

(01:53):
three thousand in the wild, is at the top of
the food chain in its habitat. Okay, What is it
that makes this lizard such a good predator? Kamodo dragon's
adult teeth are highly specialized. They're curved into a shape
like a comma, with a sharp serrated edge along the
entire curve of the tooth and extra deep ridges on

(02:16):
the inner curve that's the cutting edge. The lizards use
a puncture pull motion to tear into prey. The enamel
on their teeth is relatively thin, but that serrated edge
has a serious advantage. It's tipped in an iron infused
coating that strengthens each tooth and keeps it sharp and
turns it a little bit of a rusty orange. They

(02:38):
have some sixty teeth in total, each about half an
inch or a centimeter long, and like other reptiles and
therapod dinosaurs for that matter, they continually grow replacement teeth
in case one breaks or wears down. They have up
to five replacements for each tooth growing at any given time,
and will start to grow a new one every forty days.
That's faster tooth replacement than ever any known reptile or dinosaur.

(03:03):
The real brilliance in the Kmodo system, though, lies in
the guarantee of a meal. Their byte strength is a
bit weak compared with other large reptilian predators, and its
attack doesn't usually kill its prey out right, But a
bitten animal will almost always die within a few hours
or at most a few days. The komodo can wait patiently,

(03:25):
following it for miles in a leisurely fashion, and then
locate the dead animal by its smell. Like most lizards
and snakes, a komodo dragons have a very good sense
of smell, but it's not the kind of smell most
of us are familiar with. Like a snake, a kimodo
smells by collecting air with its forked tongue and then
depositing that air on scent receptors on the roof of

(03:46):
its mouth. Using this method, it can detect a dead
animal up to about five miles away that's eight kilometers.
Why exactly an animal usually dies after the fact has
been a object of some debate. Until the past decade
or so, scientists thought that it was a komodo dragon's
oral bacteria that killed its prey within days after an attack.

(04:10):
It's a decent explanation. A bite wounds from all kinds
of animals, including humans, can transfer bacteria into the bloodstream,
causing infection, sepsis, and organ shut down throughout the body.
It was also traditionally thought that most reptiles don't produce venom.
Venom is a toxin that's secreted by special glands and

(04:31):
injected into an animal by a bite or sting. We
knew that lots of snakes are venomous, but only two lizards,
the Gila monster and the Mexican bearded lizard, were known
to harry venom, but beginning in the two thousands, research
has proven otherwise. In two thousand and five, scientists concluded
the komodo dragons and actually all monitor lizards as well

(04:54):
as iguanas, produce venom. The researchers started looking specifically for
venom in komodo because they believed it was unlikely that
a bacterial infection could kill an animal in as little
as a day or two. They found venom in komodo saliva.
In two thousand and nine, further research involving magnetic resonance
imaging of a preserved Kmodo dragon head discovered a venom

(05:16):
gland and ducks with openings between those sharp teeth. The
researchers noted compounds in the venom that induced muscle cramping, hypothermia,
and low blood pressure, a dangerous combination, especially since the
venom also contains anticoagulants. Basically, without serious intervention, most animals

(05:36):
bitten by a komodo will go into shock and bleed out.
It's not as potent as a cobra venom, which can
kill in minutes but still undeniably fatal. In the case
of large animals like water buffalo, for which the amount
of venom transferred during a couple of bytes might not
matter much. The komodo dragon's aforementioned mouth bacteria might help

(05:58):
finish the prey off. The deepness of the bites might
allow environmental bacteria to enter the wounds. Because kmodo dragons
don't get sick from the bacteria in their own mouths,
it's thought the components of their blood might have applications
in medical research. Back in twenty seventeen, a team of
researchers found a promising peptide in komodo blood and used

(06:21):
it as inspiration to create a synthetic peptide that's antibacterial.
It both weakens bacteria membranes, making them less able to survive,
and it prevents them from forming up into tough biofilms,
which could help us fight antibiotic resistant diseases. And compounds
found in various venoms have been used to create treatments

(06:42):
for everything from high blood pressure to diabetes. Here's hoping
that this and other research and komodo dragons fascinating adaptations
might lead to lots of real world applications. Today's episode
is based on the article Arkmoto Dragon's mouths Deadlier than

(07:02):
Cobra's venom on how stuffworks dot Com, written by Julia Layton.
Brain Stuff is production by Heart Radio in partnership with
how stuffworks dot Com and is produced by Tyler klang A.
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