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Discovering Butikaw a New Species of Monitor: A Case Study

By: Dr Gareth Evans - Updated: 21 Aug 2012 | comments*Discuss
Butikaw Bitatawa Varanus Monitor Lizard

For the most part, animals that are new to science tend to be fairly small; it’s being little and relatively inconspicuous amongst the undergrowth that allows them to avoid detection for so long, despite the relentless incursions of humans into their natural habitats. The novel discovery of large species, particularly in a relatively heavily populated and fairly deforested area, is much more unusual – and when that creature in question is a 2-metre long, brightly patterned lizard, weighing 10kg, it is all the more remarkable.

A Well Kept Secret

As is often the case, the existence of this creature was well known to the indigenous Ayta and Ilongot tribes people who share this monitor’s mountainous home in the northern Philippines – in fact they’d been eating what they knew as the Butikaw or Bitatawa for centuries! Scientific suspicions that there was a new species lurking in the region, however, only really arose in 2001, when a photograph of a Butikaw that had been killed for the pot came to the attention of a group of biologists. Eight years later, suspicion began to turn into certainty after a visiting student from the University of Kansas by the name of Luke Welton, obtained the first known example of the new monitor from one of the tribal hunters.


Back in Kansas, the dead lizard was examined extensively by a team lead by the University’s Dr Rafe Brown to determine if it was simply an unusual pattern variation of Gray’s monitor (Varanus olivaceus), or whether it really was something altogether new. After a careful scale-count, meticulous investigation of its internal organs and having its DNA sequenced, the team were sure – and the reptile world had a brand new species!

Varanus bitatawa, the Northern Sierra Madre Forest monitor, was formally described in April 2010, its official scientific label reflecting the name by which it had been known – and eaten – by local people for hundreds of years.

An Odd Group

Although this animal is obviously a relative of the Komodo Dragon and all the other monitors around the world, it and its immediate kin form a particularly unusual group. Along with Gray’s monitor and the Panay monitor (V. mabitang), the Forest monitor is almost entirely frugivorous, eating a range of local fruits, particularly from the Pandanus tree, seemingly supplemented by the occasional snail.

They are also remarkably arboreal in their habits, spending most of their lives high in the trees – routinely 20 metres or more up – only venturing down onto the ground for around 15 minutes a week. Conservationists studying the new species have speculated that this may have been one of the main reasons why the monitor had managed to escape detection for so long. Daniel Bennett, one of the team involved in studying these rare animals, has described them as “incredibly secretive”; it seems that may be a bit of an understatement. Certainly if the Butikaw behaves in the same way as the closely related Gray’s monitor (known locally as the Butaan), it will almost never leave the forest to cross open areas of ground – and that makes the chances of spotting one pretty low, despite all its gold spots.

An Important Discovery

The discovery of any new animal is, of course, important, but what makes this one additionally significant is what it implies for the chances of finding other large “unknown” reptiles in relatively small areas. It appears that this monitor lives in a restricted strip of mountainous forest on the island of Luzon, separated by three river valleys and 90 miles of terrain from the habitat of the related Gray’s. If physical barriers are enough to enable two “sister” species to develop on this small island, there are probably other pairs to be found elsewhere in the Philippines, and indeed the world.

It is an exciting prospect, but clearly recognition alone will not be enough; loss of habitat already threatens the Gray’s monitor and studies may well ultimately reveal that the Butikaw is endangered for the same reasons. Only time will tell if this remarkable new species will join the depressing list of animals that have been discovered and become extinct within the same century, but if Welton, Brown and Bennett have anything to do with it, the Northern Sierra Madre Forest will keep its monitor for years to come.

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