A few months after the last of the elephants left Chicago's Lincoln Park Zoo in May, amid complaints from activists that Illinois doesn't have a climate fit for such animals, remains of their ancient relatives were showing up around the state.

"It almost seemed that mastodons and mammoths were falling out of the trees for a few weeks," said paleontologist Jeffrey Saunders, the curator of geology at the Illinois State Museum in Springfield. He's frequently the expert called in to verify and identify the teeth, bones and tusks of the giant Ice Age mammals when they are found in the state.

Saunders was a very busy man in September.

One of his trips was to a site on Sugar Creek in Logan County, where a Lincoln College freshman found two mammoth tusks while studying river mussels. He also went to Pratts Wayne Woods Forest Preserve in DuPage County, where a contractor found mastodon teeth while working on a wetlands restoration project. Saunders' subsequent digging there turned up a rib and tusk fragments.

And on the same day the teeth were found, a man developing a golf course in Kendall County called Saunders to say one of his workers had found a mastodon tooth there, and he wanted to know how much to pay him for it.

He said the recent spate of findings may be due to this summer's drought, which shrank the wetlands where mastodon remains are usually found. It also may reflect the spread of construction projects into Chicago's outer suburbs.

"But whatever the reason, there's no doubting that we have a rich record of large Pleistocene fauna here in Illinois," Saunders said, referring to the giant mammals of the last Ice Age. "There are about 80 localities of record here for American mastodons, and about 60 for mammoths. And I'd suspect that probably only one out of every 10 finds is reported. I'd love to know how many remains are being used as doorstops or are sitting in private curiosity cabinets."

One long-hidden find was by John Dewey Thomas, who unearthed two mammoth teeth while building a new house in unincorporated Wilmington 25 years ago. Thomas told The (Joliet) Herald News recently he tried to keep the teeth a secret for nearly 20 years because he was afraid someone would dig up his yard. But Thomas has since gone public with his find, and has achieved new local fame, thanks to the artistic talents of his daughter-in-law, Donna Thomas, of Belvidere. She recently completed a 25-by-60-foot mural of mammoths on the side of a metal pole barn on his property.

Saunders said that since the animals were mammoths, rather than mastodons, the lack of new remains was typical.

"Mastodons browsed off trees and lived in wetlands, so they were occupying their own burial grounds, and we often find fairly complete specimens," he said. "But mammoths were grazing animals that haunted the grasslands where the glaciers had just retreated. They lived and died in open fields, and their remains were scattered. Streams often carried their teeth and bones into wetlands and gravel pits."

While both mastodons and mammoths were quite prevalent in Illinois until some 10,000 or 11,000 years ago, Saunders said, there's no way of knowing what their total populations were. And although both animals resembled modern elephants, they were not closely related to each other.

"You can think of elephants and mammoths as first cousins, but mastodons were only distant relatives," he said.

"Mammoths were hairier than modern elephants, and had longer tusks, but they stood tall like elephants, had the same sort of teeth and the same high-domed skulls," Saunders said. "Mastodons were huge, but low-slung, and their teeth were a completely different shape. Their skulls were long and flat."

Saunders said that in Illinois, mammoths typically seemed to have roamed glacial plains about 60 miles to the north of the swamps where the mastodons were living. He said both beasts died out — along with more than 30 other types of large mammals — during North America's Great Extinction about 10,000 years ago.

"There hasn't been a smoking gun found for the Great Extinction, but there are several hypotheses," he said. One is sudden environmental change, another is overhunting by early humans and a third is that the animals were killed by diseases probably brought from Asia by the early humans, he said.

"Some people are now willing to merge hypotheses, and some aren't," Saunders added. "I personally feel that nature loaded the gun, and man pulled the trigger."

Saunders said no one knows when the last mammoth or mastodon died, but the animals lived on enough in tribal memory that when Thomas Jefferson (who collected mammoth remains himself) sent Lewis and Clark west in 1803, he told them to keep an eye out for such animals.