Martin Schneider, 60, of Blue Bell, got the teeth of the endangered whale in Britain and smuggled them into the country by hiding them among other goods he was importing. Prosecutors said he sold more than $500,000 worth of teeth from 1995 to 2005.

Lewis Eisenberg, 61, the former director of The Whalers Village Museum in Lahaina, bought teeth and resold them to collectors, many of whom trade in scrimshaw, an art form in which designs are etched into whale bone. Eisenberg, of Oak Harbor, Wash., sold teeth he got from Schneider for more than $45,000.

Both men pleaded guilty to violations of the Endangered Species Act, the Mammal Protection Act and the Lacey Act, which forbids the import or export of wildlife that is illegally transported or sold.

Acting on a tip, federal agents bought two whale teeth from Schneider in March 2005 for $2,100. Later that year, customs agents at Philadelphia International Airport intercepted a package of his that contained eight more teeth, authorities said.

Investigators then went to his home in suburban Philadelphia and found records showing he had sold $540,000 worth of teeth over 10 years.

Schneider's attorney, Gerald Stein, said his client believed the teeth came from whales that were killed by Russian fishermen before the implementation of the Endangered Species Act.

"He thought that these teeth were acquired at a time when it was legal to acquire them," Stein said.

An attorney for Eisenberg, Daniel-Paul Alva, said his client used bad judgment.

"He was silly," Alva said. "He knew it was wrong."

Both attorneys said they hoped their clients would be sentenced to probation, not prison.

Under federal guidelines, prosecutors said Schneider will likely get 30 to 37 months in prison, while Eisenberg is likely to get 10 to 16 months. Both face thousands of dollars in fines.

Authorities said the arrests came as part of a nationwide investigation, which has led to one other conviction in Hawai'i. But many collectors who bought teeth have not been located.

Assistant U.S. Attorney Manisha Sheth said that agreements from both clients to cooperate in the investigation could help nab additional suspects.

Investigators also hope such arrests can help crack down on the sale of whale teeth and other endangered animal parts. Wildlife smuggling is a multibillion-dollar illegal industry that federal officials describe as the second-largest black market behind narcotics.