Enclosure status
IUCN status
Scientific name
Varanus macraei

Blue tree monitors have a prehensile tail which they use to travel between the branches. They are isolated to a small island in Indonesia, Batanta, which is around the same size as the Isle of Wight. 

Blue tree monitor facts

  • This strikingly coloured lizard was only described by science in 2001, by 2003 it could already be found in the wildlife trade, where its bright colouration and novelty meant it commanded a high price.  
  • The species is known to exist in the wild only on Batanta Island and the surrounding islets off the coast of Irian Jaya, Indonesian New Guinea. Batanta island has a total area of just 455 km2 meaning this species has one of the smallest distributions of any monitor lizard.
  • Locals report that it is no longer present on one of the offshore islands on which it was known to occur due to over collection for the international pet trade.
  • The overall commercial value of exports of this species from Indonesia over the past decade is estimated at $1.15-2.01 million.
  • In the period 2003– 2010, Indonesia claimed 1,670 exports of individual blue speckled monitor lizards.
  • Our ZSL team recently documented play behaviour in this species and studied the effects of different enclosure heaters on behaviour. Both studies were published.
Blue tree monitor climbing
Blue tree monitor on a branch

Blue tree monitor puzzle solving

Blue tree monitors are very intelligent, and are known for their ability to problem solve. Our blue tree monitor, called Ayem after their native home, is given puzzle boxes to test his cognitive skills and find food. 

Blue tree monitor threats

Collection for the international wildlife trade which is compounded by the restricted range of this species makes it particularly vulnerable to overexploitation.

Our reptiles

  • King cobra
    Ophiophagus hannah

    King cobra

    These massive snakes grow 18 feet long and primarily eat other snakes.

  • Philippine Crocodile at London Zoo
    Crocodylus mindorensis

    Philippine crocodile

    There are one only around 120 left in the wild, but we are working to recover Philippine crocodiles at the Zoo and in the field.

  • Two Galapagos tortoises at London Zoo
    Chelonoidis niger

    Galapagos tortoises

    With a lifespan of 177 years old, some Galapagos tortoises alive today would have around since before the American civil war. 

  • Anam leaf turtle at London Zoo
    Mauremys annamensis

    Annam leaf turtle

    The anam leaf turtle is one of the most endangered reptiles on earth, there are only around 50 remaining individuals in the wild. Little is known about them, but we are working to better understand the species.