Bert Langerwerf was 10 years old when he first became interested in lizards. He found a small lizard in a ditch by his home in the Netherlands and was immediately fascinated by the creature.
That was 50 years ago. Today, Mr. Langerwerf lives in America and still loves lizards. But now he breeds and sells them to people all across the country who share his fascination for these amazing critters.
In 1988, Langerwerf settled in Alabama because the warm climate was ideal for raising many types of lizards. "The weather in Holland was not good to raise reptiles," he says. "It was too cold and wet."
People like Langerwerf, who breed reptiles as a hobby and sometimes sell them, are called herpetoculturists, according to Ken Marion, a biology professor at the University of Alabama at Birmingham. The scientists who study the biology of reptiles are called herpetologists.
Even though Langerwerf is not a trained herpetologist, he knows a lot about lizards. Much of what he learned he taught himself by studying lizards, reading books, and talking with other people who have kept lizards.
He has bred more than 150 species, many of them for the first time in captivity, and has made some important discoveries about lizards.
In 1976, Langerwerf discovered that in certain species, it was the temperature of the lizard eggs in the nest that determined whether the lizards would hatch to become males or females (see sidebar above for another of his discoveries).
He has also written several hundred articles about lizards for scientific magazines and journals, and receives many invitations to travel around the United States and overseas to talk about lizards. Langerwerf has earned the respect of herpetoculturists and herpetologists around the world.
He says there are many types of interesting lizards in the US. One of his favorites is the anole (pronounced a-NO-lee), which is most often seen in the Southeast. He says anoles are easy to spot, because the males have what's called a dewlap, a pink fan-shaped flap of skin on their throats.
"They show their dewlap to attract females or chase away other males," says Langerwerf. "They can also change color like chameleons. But they are actually related to iguanas, not chameleons."
Most of the lizards Langerwerf raises are not native to America. That's because people who collect lizards are usually interested in the larger species that are found in other countries.
His biggest lizard comes from Argentina and is called a tegu. The babies hatch in July and sell for about $50 each. Within a year or so, they can grow to more than four feet long and have sharp claws and powerful jaws.
Tom Scollins of Baltimore, Md., who owns several lizards, has been bitten by his tegus, but says, "It was my fault for underestimating their strength."
Despite their size, Argentine tegus are usually gentle when raised in captivity, Langerwerf adds.
Nicole Russell, who lives in New Jersey, also owns some tegus. She often takes "Nico," her male tegu, to visit students in local schools so they can learn more about lizards.
"He loves children," she says, "and is really the most docile, sweet animal in the world."
Langerwerf recently visited Mountain Brook Elementary School in Birmingham, Ala., where the fifth-grade classes were doing a project on lizards. In addition to a young tegu, he took along an Australian water dragon. These are big lizards, too, about half the size of a tegu, and live along the rivers of eastern Australia. The males have beautiful red bellies.
Naturally, the kids wanted to see the lizards up close. So Langerwerf walked around the classroom and allowed students to carefully touch them.
The students enjoyed this. Megan thought the skin felt beady and rough, while Marjorie thought it felt like a loose-fitting jacket. "Lizards are cool, awesome creatures," she said.
Katherine received a special thrill. "One of them sniffed me with his tongue," she said, when the tegu's forked tongue darted in and out of its mouth and brushed against her fingers.
"What do lizards eat?" asked one student.
Langerwerf told them that his wife, Hester, visits local grocery stores to collect leftover bread and vegetables, which she feeds to the animals. He said he also breeds rats, which provide live food for some of the larger lizards.
Since lizards also eat insects, Langerwerf brought along a jar containing several six-spotted cockroaches. These are two-inch-long bugs that his lizards love. He let one crawl on his hand, but it fell on the ground inches in front of the students, who were sitting on the floor throughout the presentation.
"Oops!" he said with a grin on his face as the class erupted with screams, and a brief "roach-on-the-loose" panic swept through the room.
After recapturing the giant roach, he went on to tell the class that lizards in the wild are beneficial to people, because they eat insects. He also reminded the kids that all his lizards are bred in captivity and that they should not buy animals that have been taken from the wild.
"It's not good to upset the balance of nature, and we might even contribute to the extinction of rare animals," he said.
After the visit, a teacher, Suzanne Andrews, said the class really enjoyed the hands-on experience: "This whole project gave the kids an opportunity to take a closer look at their environment. I hope they learn about lizards, what it takes for them to survive, and the role they play in our ecosystem."
• Find more information about Bert Langerwerf and his lizards at his website, www.agamainternational.com.
In the warmer parts of the United States, you may be able to find a number of lizards in your backyard. Here's how to identify some of the most common:
Anoles are identified by their pink dewlaps (or flaps of skin hanging from their throats). They can change color from green to brown and back again in just a few seconds.
Broad-headed skinks live on the ground, like most skinks, but also like to climb trees. They have dark- colored bodies with stripes. Their bright blue tails fade as they get older. Males usually have a red or orange head.
Fence lizards like to sit on fences on sunny days. They're hard to catch, as they dart away if you get too close. Males have patches of blue on their throats and bellies, while females have dark wavy lines on their backs.
Racerunners are some of the fastest lizards in the world. They have six light stripes along their brown bodies.
Glass lizards are often mistaken for snakes because they can grow to several feet long and have no legs. Few adult glass lizards still have their tails. Although lizards' lost tails usually grow back, glass lizards' tails break off very easily.
About 30 years ago, Bert Langerwerf made a scientific discovery about lizards that even herpetologists (scientists who study lizards) didn't know. His experiments showed that lizards need sunlight.
This was an important discovery for all lizards in captivity, says Randy Smith, a reptile keeper at the Birmingham (Ala.) Zoo. It showed there was a close connection between lighting and the animals' well-being.
Today, zoos and those who keep many lizards know that it's important to give these reptiles proper lighting. Indoors, that usually means using UVB (ultraviolet) fluorescent lights where the lizards live.