Migrant Lizard, Having Made It in New York, Heads Elsewhere – via Herp Digest

by Jim Dwyer, 8/25/16 New York Times 

For centuries, New York City has been the gateway to a new land, and now residents believed to have originated around warm, sunny Tuscany are moving on after a few years of city life. How they managed to get by in this colder, more crowded climate is being studied by Colin Donihue, a biologist doing postdoctoral studies at Harvard University.

“It looks like they’ve moved up the Metro-North line into Connecticut,” Dr. Donihue said. “There’s also a population in Hastings-on-Hudson.”

His subjects are Italian wall lizards, escapees from pet stores in the Bronx and on Long Island during the past 40 to 50 years. They are less than four inches long. On the ground, they move at Usain Bolt speeds. They are also sprinters in evolutionary change.

“It’s a body plan that has been around for hundreds of millions of years,” Dr. Donihue said. “That’s the cool part of this story. We have this historical perspective that evolution is one of these processes that takes a really, really long time. But we’re also finding that evolutionary changes can take place over a few generations.”

The same lizard family proved its rapid adaptability when it was introduced to an island off Croatia. Instead of their usual fare of all insects, all the time, the lizards began eating flowers, berries and leaf bits. A researcher found that after being on the island for 36 years, they had developed a new pocket in their gut to help them process the plant material. What the New York branch did to survive city life and migration north is being studied by Dr. Donihue and Max Lambert and Greg Watkins-Colwell, colleagues at Yale University.

The adaptability of species to urban life is an area of blooming interest; cities are the dominant human ecosystem. Their intense environments make them ideal laboratories for watching the pace and character of change, as Menno Schilthuizen wrote in The New York Times’s Sunday Review last month. In Vienna, spiders learned to build webs near streetlights, letting them catch a bounty of moths. In Amsterdam, Madrid, Berlin and Prague, among other places, European blackbirds that left the forests for cities now sing at a higher pitch so they can be heard over traffic, and have developed calmer temperaments.

The boundaries of ecosystems, never really fixed, have been broken by long-distance air and ship travel. Bird-eating snakes got to Hawaii in the landing gear of airliners, and feral camels wound up roaming Australia, as Alan Burdick chronicled in his acclaimed 2005 book, “Out of Eden: An Odyssey of Ecological Invasion.”

How did the Italian lizards get to New York? A Bronx commercial pet dealer sold about 120 of them in the late 1960s as natural pest control to the township of Mount Laurel, N.J. Legend has it that a pet truck got in a crash in the Bronx. “That’s the origin myth,” Dr. Donihue said. More reliably documented are the lizards that made a break for it about 15 miles from the Bronx, getting out of a damaged carton at a pet store in West Hempstead, N.Y. Still others were released in Ohio, Kansas and British Columbia.

Around New York City, the lizards have been found in at least four of the five boroughs: at Queens College in Queens; the New York Botanical Garden and Pelham Bay Park in the Bronx; Washington Cemetery in Midwood, Brooklyn; and Baker Field in Upper Manhattan.

The Italian lizards are not pushing out native New York lizards; there were none. “Across the board, this is just an interesting ecological oddity,” Dr. Donihue said.

His study of their movement into Greenwich, Conn., was reported last month by Peregrine Frissell in The Hour, a local newspaper. Dr. Donihue hopes to track the lizards, though he has yet to find any tags that fit. He wants to find out how far north they can move, and what they do to survive winters much colder than in their native range. As hiding spots from predators like cats, snakes and birds, the rocky beds of the train tracks could be lizard nirvana, Dr. Donihue noted.

If these lizards are leaving the city for Connecticut, it is the reverse of the journey of Chester Cricket, the star of the 1961 book “The Cricket in Times Square.” Smelling liverwurst, Chester hops into a picnic basket in Connecticut and ends up being cared for by a boy whose family runs a newsstand in the Times Square subway station.

Do the lizards have a lovable classic in them?

“I think it’s possible they are jumping on a train,” Dr. Donihue said. “But it’s more likely that they are just running up the train tracks. They’re really fast, and it’s a straight runway.”