The Los Angeles Zoo has welcomed a trio of new lizards … and they’re pretty special. Staff were thrilled to announce the successful hatching of three healthy Gray’s (or Butaan) monitor lizards (Varanus olivaceus), marking only the second time that this Asian species has been bred successfully in the Western Hemisphere.

“We have had clutches of eggs in the past, but this has been the healthiest fertile clutch,” said Ian Recchio, curator of reptiles and amphibians at the zoo. The facility is home to the only known breeding male of the species, and it's also one of only two US zoos accredited by the Association of Zoos and Aquariums (AZA) that is working with Gray’s monitors. 

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Image: Ian Recchio

One of the largest lizards in Asia, Gray’s monitors are extremely shy and spend most of their time in the trees, so very little is known about their reproductive cycles. The secretive species was thought to be extinct in the wild for over 130 years, until it was rediscovered inhabiting a handful of islands in the Philippines (where the lizards are thought to inhabit an area of just 20,000km²). The olive-green reptiles can grow to 6 feet (1.8m) in length and weigh up to 20 pounds (9kg).

The zoo's eggs were incubated over a 270-day period under the optimistic watch of reptile zoo staff who had to draw on experience hatching similar Asian species like Komodo dragons. Although the zoo has been home to Gray’s monitors since 1998, the animals were received through illegal confiscations, so staff have never dealt with hatchlings before.

Their unusual diet of indigenous invertebrates and fruit from the Philippines makes it very tricky to keep Gray’s monitors in captivity, and zoo staff are forced to experiment a bit to make sure the "lizardlings" get the sustenance they require.

“We treat them like smaller versions of the adult monitors,” Recchio explains. “Sometimes we have to get pretty creative to get these monitors to feed, and we’ve been known to try tricks like injecting baby food into the dead mice they eat. Currently this clutch is responding best to food items such as snails, insects and smaller pieces of fish.”

It's hoped that the new arrivals will help grow our knowledge of this vulnerable species and expand the breeding programme in the US. “Before you can establish a captive breeding and conservation program, you have to understand how to keep the animal alive and ultimately how to reproduce it in captivity,” said Recchio. “We have taken huge strides forward in understanding the captive management of a rare and poorly understood Asian lizard.”

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An adult Gray's monitor lizard photographed at the Los Angeles Zoo. Image: Loren Javier

Although the baby monitor lizards are being kept in isolation, guests can still view the adult Gray’s lizards at the Living Amphibians, Invertebrates and Reptiles (LAIR) building at the Los Angeles Zoo. And with a fresh clutch of eggs currently incubating in the zoo’s holding facility due to hatch in July, there may just be a whole heap of mini-lizards on display in the near future!