Indonesia's fierce dragons

A large, stocky lizard ambles to a shaded spot near a watering hole and lies patiently in wait. It blends in with the surrounding vegetation and as a water buffalo stops for a drink, the reptile explodes into action, its sharp claws and teeth tearing into the prey.

Known as Komodo dragons, these monitor lizards are near perfect predators and will eat anything from carrion to humans on the Indonesian islands they've made home.

They can reach up to 10 feet (three meters) in length and achieve an adult weight of around 300 pounds (136 kilograms), making them the heaviest lizards on earth. Nonetheless, over short distances, they can run as fast as man. 

But their speed and size are only part of what makes them dangerous. Having torn into their prey, they inject it with powerful, anticoagulant venom that lowers blood pressure. Even if the victim manages to escape the Komodo dragon's jaws, it will bleed out as it tries to find a place of safety.  

Once the dragon has secured and slain its prey, it settles in for a huge feed. It can consume up to 80 percent of its own body weight in a single sitting and only needs to eat every few weeks. The rest of the time, it does what lizards do best — lounge around in the sun.

Playful predators

The stuff of nightmares though they may seem, Komodo dragons aren't all claws and sharp teeth. Researchers believe they also like to engage in play similar to that of cats and dogs. One female at the Smithsonian Zoo in the US capital Washington D.C., alerted researchers to this behavior when she developed a close bond with her keepers, according to Science Blogs. 

Kraken, as the dragon is called, would tug at shoe laces and objects in her keepers' pockets, so staff at the zoo began to introduce boxes, blankets, frisbees and other items. A study of her behavior concluded that she was playing with the objects, indicating that such reptiles have much more complex cognition than previously thought.

No males required

Female Komodo dragons are among the tiny number of vertebrates that can reproduce asexually. They do so through parthenogenesis, which sees the mother's half set of chromosomes double up to create a full set, so no sperm is needed.

Zookeepers observed asexual reproduction in two females at zoos in the United Kingdom in 2006. The females had been kept separate from their male counterparts but — to the surprise of their keepers — became pregnant. A genetic analysis of the females showed no male had fertilized the eggs. 

Researchers believe the Komodo dragons evolved this ability because of their remote natural habitat. It may have helped them to spread to other islands in the Indonesian archipelago, wrote Scientific American at the time of the discovery.

Dragon's blood

It also seems that the Komodo dragon has at least one other trick up its scaly sleeve. Or between its scaly jaws. When scientists realized the animal's saliva is teeming with harmful bacteria that don't seem to affect it, they started looking to the animal to help develop new antibiotics capable of fighting multi-drug resistant superbugs. 

A 2017 study carried out by scientists at George Mason University in Virginia identified 48 protein-like compounds that fight bacteria in the lizard's blood. They created a synthetic compound based on one particular molecule with antimicrobial effects, which they hope could provide the basis for future antibiotics.