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An Explorit "Science Bytes" article by Karen Cebra (2000)

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Meet Explorit's Bearded Dragons 

By: Karen Cebra

Ah! The pungent smell of the eucalyptus tree. They are everywhere in California. But did you know that eucalyptus is not a native of California?

Part of the Myrtle family, the 500 species in the genus Eucalyptus are all native to Australia. Because the climate of Australia is much like that of northern California, the 75 or so of these species (for example, Blue Gum and Red Ironbark) that have been introduced to California do quite well here. The favorable climate of California allows Australian animals to thrive as well. The San Francisco Zoo can maintain its koalas with local sources of fresh eucalyptus leaves on which the koalas depend. (Other zoos without such a source either do not have koalas or must have eucalyptus shipped to them at great cost.)

Another Australian native, the bearded dragon, does very well in California. In fact, it can survive outside year round in some parts of California. No, a bearded dragon isn't a huge, fire-breathing beast with a beard. Rather, it is a lizard with enlarged scales that cover its throat and that reaches up to two feet in length from nose to tail tip. When threatened or displaying, the animal can inflate its throat causing the scales to stand out. A predator or rival may be intimidated enough by the display that it will leave the lizard alone. 

There are eight species of bearded dragon belonging to the genus Pogona occupying habitats in Australia ranging from desert to woodland. In order to protect its native species, Australia has very strict rules regulating their export. To take a bearded dragon out of Australia would be a violation of at least Australian law and the Lacey Act. It is for this reason that the bearded dragons kept in captivity in the United States are almost entirely bred from captive animals. In fact, one species, Pogona vitticeps, predominates the captive animal population in the United States.

Bearded dragons are omnivorous, eating everything from insects to vegetation. If you see one, you will notice that it blends in very well with its background. This crypticity helps the lizard in its strategy as a sit-and-wait predator. Rather than chase down prey, an energetically expensive approach, the lizard will lie in wait for something to come near enough for it to quickly seize and eat. 

Bearded dragons exhibit a number of interesting behaviors which make them fun to watch—arm waving, head bobbing, and beard inflating among them. If you watch long enough, you can gain an understanding of what these behaviors mean. For example, an arm wave by a female may be a gesture of appeasement and a head bob by a male may be an indication of aggression. 

Much of their time "behaving" is spent lying about or basking. Part of being a reptile includes having to regulate ones body temperature externally. This can be accomplished by simply lying about on warm rocks to increase body temperature or moving into the shade to decrease it. Life is not all lying in the sun though. Bearded dragons may fight over territory or mates, especially during breeding. During this time, they are much more active.


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