Have You Hugged Your Komodo Dragon Today?

Komodo dragon, resting on a rock. Image taken at Woodland Park Zoo, Seattle.

Komodo dragons are crazy cool lizards, with no natural enemies. They’re only found on a few small islands in Indonesia and most of what we know about them we’ve only learned in the last 30 years. They are the largest living lizards in the world, averaging 150 lbs (68kg) and 8 ft. (2.4m) in length, though they’ve been known to grow as much as 300 lbs and 10 ft. in length. And actually, since they can eat 80% of their body weight in one sitting (!!), a male that just finished a large meal can be weighed at more than 550 pounds. This big lizard had big ancestors. Their largest ancestor was the Megalania prisca, which grew to over 23 ft and 1,400 pounds and was the largest venomous animal to have ever lived (as far as we know).

A resting Komodo dragon. Image taken at the Woodland Park Zoo, Seattle.

Predominantly ambush predators, these lizards can hunt animals 5 times larger than themselves and 15 times their weight, including deer and water buffalo.  Although they appear toothless, because their gums cover their teeth until they’re ready to bite, they have 60 inch-long teeth and deliver deeper and more damaging wounds than a crocodile. When they eat, their gums tear and bleed. The blood mixes with the saliva and makes a slime that allows them to swallow their food whole. Every part of the prey is eaten, even hooves, and it all gets dissolved in their strong stomach acids. The lizard may have to sleep for up to an entire week while its food digests after eating a big meal.

Resting Komodo dragon at the Woodland Park Zoo, Seattle.

Oh and they’re venomous. What’s that you say? No they’re not? You learned a long time ago that the Komodo dragon has bacteria in its mouth and it’s a bacterial infection that causes the slow, agonizing death of the prey? Yeah, so did I. It wasn’t until 2009 that scientists discovered that they are venomous. They have venom glands in their mouth and venom causes their prey to continuously bleed. They die from blood loss and infection.

Komodo dragon. Image taken at the Woodland Park Zoo, Seattle.

Nothing is safe from a Komodo dragon-not even Komodo dragons. They are cannibalistic, with healthy dragons eating the young, old or injured dragons. Young Komodo dragons make up about 10% of an adult dragon’s diet. For this reason, when young dragons hatch, they dash up into the trees to avoid being eaten. But many won’t make it. Birds, snakes and other Komodo dragons-sometimes even their mothers- will catch them before they can reach the safety of the tree. They have to be cautious and quick when they come down for water and sometimes they may roll around in feces to mask their odor from adults.

A Komodo dragon. Image taken at Los Angeles Zoo.

One reason why they eat their own young may be that they need to in order to reach their huge size. The young eat insects, and small lizards and mammals, but there are very few medium sized animals on the islands. Those that are there were introduced and so weren’t always around. Perhaps eating their own young gets them to the next size level where they can go after bigger animals.

Komodo dragon resting on a big rock. Image taken at the Woodland Park Zoo, Seattle.

These predators have excellent senses. They have a forked 16-inch tongue that works like a snake’s tongue-flicking it out into the world, they can taste/smell with their tongue. They can find carrion more than 5 miles away. They are covered in hard scales, each one with a sensory plaque for increased sensitivity. On their face and feet, each scale has 3 or more sensory plaques, further heightening their sensitivity. They can see in color. We used to think they were deaf, but that was disproved by a zookeeper that trained one to come when it heard her voice. Now we know that they only hear sounds in the low range of pitches. They can even distinguish between different human voices.

A Komodo dragon checking us out. Image taken at the Los Angeles Zoo.

Male Komodo dragons are territorial. Females and young can inhabit their territory, but males are only allowed to pass through when the visitor is tracking prey. They will fight other males to breed, standing on their hind legs and balancing on their tales. After the loser falls, he will lie still while the winner scrapes his claws along the loser’s back and tail as a sign of dominance.

Females use their claws to dig egg chambers. Since Komodo dragons will raid each others’ nests, the mother dragon will dig mazes of false tunnels to confuse any would-be egg raiders.

Komodo dragon claws, front foot. Females use their claws to dig egg chambers. Males will scrape them across defeated Komodos. Image taken at Los Angels Zoo.

Front feet of the Komodo dragon.  Image taken at the Los Angeles Zoo.

Komodo dragon claws, hind leg. Image taken at the Los Angeles Zoo.

Females will also guard their nests for up to 3 months. She’ll leave once the rainy season hits, since the chances of her eggs being disturbed are substantially less.

In 2006, we discovered another surprising fact about Komodo dragon reproduction. The females can be parthenogenetic! In London’s Chester Zoo, a female produced 8 offspring without ever having met a male, giving us our first glimpse at this cool adaptation.

Komodo dragons can live 50 years in the wild and up to 9 months without water. They are strong swimmers, able to travel between islands and dive to depths of 15 feet.

Time to cool off. A Komodo dragon about to take a swim. Image taken at the Los Angeles Zoo.

Komodo dragon going for a swim. Image taken at the Los Angeles Zoo.

People in Komodo and Rinca take precautions to avoid attacks from Komodo dragons. They don’t wander into the forests or grasslands alone and they never antagonize or approach the dragons. They’ve also had a long-held belief that if they feed the old dragons that could no longer hunt, throwing them old deer heads and hides and fish heads and guts, it was sort of a peace offering and it kept them and their children safe from getting attacked. Younger dragons sometimes ate the food as well. There was only 1 human death recorded in 30 years (since records started) from 1965-1995.

However, in 1995 Komodo park authorities banned the feeding of Komodo dragons, which environmentalists thought would make them grow lazy and forget how to hunt themselves. They also outlawed the dogs, which are considered an invasive species, which have been used to keep the dragons out of the villages. Since these things have been put in place, several people have been killed by Komodo dragons since 2000 and some dragons have recently begun to enter school buildings and homes. That’s right. Imagine a giant 8-foot venomous lizard walking down your school hallway.

Komodo dragon. Image taken at the Los Angeles Zoo.

It may surprise you to know that King Kong was actually based on an expedition to collect Komodo dragons. The best trappers had extreme difficulty and the dragons were escaping. The movie producer Merian C. Cooper took the story and changed the giant lizard to an ape.

Komodo dragons appear in a few other movies as well. In The Freshman they used an Asian water monitor to be a “Komodo dragon.” In Komodo Dragon, the dragons are computer generated. It turns out that real Komodos don’t do well with handling.

You can also find cool Komodo dragon art, like this awesome statue that lives at the Woodland Park Zoo in Seattle, that kids are allowed to climb on.

A Komodo dragon statue in Woodland Park Zoo, Seattle. There are brightly colored tiles along its back. Children are allowed to play on it.

Alright, one last cool tidbit on this really long post. At a Singapore Zoo, they’ve used acupuncture to treat a sick dragon. It’s thought to have been successful.

Have one last photo of these beautiful animals.

Komodo dragon, clearly contemplating the meaning of life. Image taken at the Los Angeles Zoo.

What’s going on?

Dear Backyard Zoologist readers,

You’ve probably noticed a huge drop off in posts recently and I wanted to let you know what’s going on. In all honesty, I began this blog over a year ago because I enjoy sharing information and pictures of awesome wildlife. I still do, but at the moment I have a lot of cool but time consuming things going on and creating these posts on a regular schedule is starting to become more of a chore than something I do for fun. So, I’ve decided to only write new posts when the spirit moves me instead of on a regular schedule, to eliminate the dreaded deadline of Monday and Friday. Still, I hope you’ll check in periodically to see what’s new or better yet, sign up for e-mail notifications to let you know when I do post something new.

I still have lots to share…for example, did you know that this animal:

A giant green Anemone. Image taken at Fitzgerald Marine Reserve tidepools in California.

is used as a vertebrate heart stimulant? Or that this animal:

A 9 banded armadillo. Image taken at the San Francisco Zoo.

always gives birth to identical quadruplets? And naturally grows the bacteria responsible for leprosy on its feet? Scientists couldn’t cultivate this bacteria in a lab, so they brought in live armadillos to collect the bacteria to work with.

Or that this animal:

A tree shrew. Image taken at the Oregon Zoo.

Is very smart and has a larger brain size to body mass than humans do?

Or that this animal:

California kingsnake, Kali, my personal companion.

Is called a kingsnake because it eats other snakes, including rattlesnakes and is immune to rattlesnake venom?

Or that these animals:

Rock doves, a.k.a. pigeons. Image taken in San Francisco.

are one of the few birds that feed their young a type of milk?

Or that this animal:

A marine toad. Image taken at the San Francisco Zoo.

is one of the only toads that will sometimes eat vegetation and dead things? While other frogs and toads want to eat only moving things, this toad is even attracted by dog and cat food left in yards.

Or that this animal:

A lionfish. Image taken at the California Academy of Sciences.

is covered in highly venomous barbs and that dolphins will sometimes grab these fish by their tummies and use them as weapons to catch fish hiding in crevices?

They See Me Crawlin’, They Hatin’

A Northern Pacific rattlesnake. Image taken at the California Academy of Sciences.

Rattlesnakes! Very common and very venomous snakes on the west coast and fascinating reptiles to learn about. Where to begin? I suppose the most common questions I’ve encountered about snakes have to do with their venom and the way they catch and kill food.

Humans are most likely to have problems with rattlesnakes when the snakes are feeling threatened and are defending themselves. Venom is actually very energy expensive to make and not beneficial to the snake to waste, so if a snake is aware of you and it can get away, it is likely to disappear before you’ve even noticed it. But, if you do cross a rattlesnake and it is threatened, usually it will give you a warning by shaking its rattle as a threat. Usually. Young rattlesnakes do not yet have a rattle, and the pieces or “beads” of its rattle will come with each shed. (You can’t actually tell how old a rattlesnake is by its rattle because pieces of the rattle can fall off and the number of sheds a snake has varies.)This fact is most unfortunate, because young rattlesnakes are actually more dangerous than adults. Adult rattlesnakes control the amount of venom they use to try to conserve it, whereas the young don’t hold back venom.

There is another reason why this warning is sometimes absent. Humans are selecting against it. Human fear of rattlesnakes often causes them to kill rattlesnakes when they are discovered. Therefore, the snakes that don’t make their presence known are the ones that are surviving and reproducing. Apparently, the number of rattlesnakes not giving this warning anymore is significantly increasing. So thank you, ignorant humans.

A Northern Pacific rattlesnake's rattle and its distinctive stripey tail. Image taken at the California Academy of Sciences.

In any case, usually a rattlesnake will rattle and hopefully the creature that stumbled too close respects the warning. If not, the rattlesnake will bite to defend itself. Sometimes the bites are “dry bites,” where the snake bites but does not inject venom. And sometimes they are not. The NIH has some excellent suggestions for how to avoid snake bites and what to do if you are unfortunate enough to get bitten here. My favorite piece of info gleaned from this site? Don’t pick up dead snakes because they can still bite up to an hour after death. ZOMBIE SNAKES!!! (Or a really strong biting reflex.)

So, venom and rattle are a great defense. So great that rattlesnakes even have non-venomous mimics. Gopher snakes have a similar coloration to some types of rattlesnakes and will shake their tail in dry leaves and hiss to mimic the sound and the appearance of a rattle. Rattlesnake defense is very important because far from being top predators, these animals are right in the middle of the food chain. Various birds of prey, especially red-tailed hawks are known to consume these snakes.

Venom does not always work as the best defense, however. Kingsnakes, for example, are immune to rattlesnake venom and will eat rattlesnakes. Ground squirrels are also immune to Northern Pacific rattlesnake venom and will exhibit mobbing behavior, aka ganging up on them. So these animals have a lot to worry about.

But, they are not always the victim. They are also the hunter. Awesome hunters. Rattlesnakes have an extra sense to help them hunt. Take a look at the image below. See the big circular spot under his eye, above his mouth?

A Northern Pacific rattlesnake. Note the circular heat sensing pit. Image taken at the California Academy of Sciences.

This is a heat sensing pit. So, when you hold your hand over a stove, you can tell its hot without touching it right? Well imagine if that sense was so strong, you could feel the body heat of a furry creature at a distance. That’s what that pit does. So, even if the wind is blowing in the opposite direction and the snake can’t smell food, it can still find its prey. Neat, huh? And it uses its venom to hunt as well. This rattlesnake pictured here will bite its prey and let it go, but follow it until the animal stops running. The venom will actually partially digest the animal for the snake before it gets to it.

They’re not just great predators and great defenders, but the Northern Pacific rattlesnake is also one of the few snakes to exhibit any form of “parental care.” That is, young rattlesnakes are allowed to stay with their mother for a few weeks and gain protection from her presence. When its time to hibernate, they follow their mother’s scent trail to the same den year after year. Some of these dens have been occupied for over 100 years!

And one last way that these snakes might surprise you…they are actually great swimmers and have even been found several miles out to sea.