Head to head
Komodo Dragon vs Asian Water Monitor
The Komodo dragon is a monitor lizard, in the same genus, Varanus, as the water monitors, tree monitors, and the perentie. It is simply the largest of them, and an unusually specialised one. Setting it beside the Asian water monitor, the lizard most people picture when they hear "monitor," shows how far one branch of the family has gone.
| Komodo Dragon | Asian Water Monitor | |
|---|---|---|
| Scientific name | Varanus komodoensis | Varanus salvator |
| Weight | 70 kg average, up to 80 to 90 kg | Typically 15 to 25 kg |
| Length | Around 2.5 m, up to just over 3 m | Up to about 3 m, mostly tail |
| Range | Four islands in eastern Indonesia | South Asia through Southeast Asia to Indonesia |
| Diet | Ambushes large mammals; also carrion | Generalist: fish, crabs, rodents, birds, eggs, carrion, refuse |
| Habitat | Dry savanna and monsoon forest on islands | Rivers, mangroves, coasts, farmland, and city canals |
| Venom | Yes, with a strong anticoagulant effect | Yes, as in all monitors, but with little effect on people |
| Conservation status | Endangered | Least Concern |
Komodo Dragon vs Monitor Lizard: common questions
Is a Komodo dragon just a big monitor lizard?
Essentially, yes. The Komodo dragon belongs to the genus Varanus, the monitor lizards, which contains around 80 species from the tiny short-tailed monitor of Australia up to the Komodo dragon and the crocodile monitor. It shares the family's forked tongue, long neck, powerful limbs and claws, and, as recent research has shown, venom glands in the lower jaw. What sets the Komodo dragon apart is its size, which is the largest of any living lizard, and its ecology as an ambush hunter of large hoofed prey, made possible on its islands by the absence of big mammalian predators and by a past when the islands also held dwarf elephants. It is the monitor design scaled up and pointed at big game.
Which is more dangerous to people?
The Komodo dragon, clearly. It is large and powerful enough to see a person as potential prey or a serious threat, its bite combines deep slashing wounds with venom that prevents clotting, and there is a short list of documented attacks on humans on the Indonesian islands, some fatal, usually involving children or people who got between a dragon and a carcass. Visitors are always accompanied by rangers with forked staffs. The Asian water monitor is far less of a concern: it is usually wary and flees into water, and although a large one can deliver a painful bite, a tail lash, and deep scratches if cornered or grabbed, unprovoked attacks are essentially unknown, and the millions of people who live alongside water monitors in Asian cities generally ignore them.
Why is one Endangered and the other doing fine?
Range and adaptability. The Komodo dragon exists only on a handful of small islands, so its total population is only a few thousand and it is inherently vulnerable to fire, disease, poaching of its prey, tourism pressure, and sea-level rise shrinking its habitat. The Asian water monitor occupies an enormous swathe of Asia, breeds well, and is a supreme generalist that actually benefits from human landscapes, feeding at fish markets, rubbish dumps, and drainage canals. It is one of the most heavily traded reptiles in the world for its leather, with millions of skins exported, and yet its range and flexibility keep it classed as Least Concern.