The Pennsylvania Game Commission has determined the ingestion of plant parts from a common ornamental shrub is the likely cause of death for a 300-pound female bear and her three cubs.

The family of four was found Dec. 6 near a church parking lot in West Wyoming, according to the Pennsylvania Game Commission."The bears showed no signs of bullet wounds or other external trauma and were found dead in or around the same tree. There was no evidence of thrashing or stumbling in the area around the bears, suggesting they died suddenly," said the commission in a released statement.The unusual condition the bears were discovered in prompted the Game Commission to consider the deaths suspicious, requesting anyone with information regarding the incident to contact the agency.The Commission transported the sow and one cub to the Penn State Animal Diagnostic Laboratory in State College for autopsy and toxicological testing with the remaining two cubs retained at the region office.The findings released after an examination of the stomach contents of both bears revealed the recent consumption of leaves and seeds from an English yew (Taxus baccata) plant.The yew is a coniferous tree native to Europe, Africa, and southwest Asia. The plant has lance-shaped leaves and produces a red berrylike cupped structure called an "aril" that contains a single brown seed. An English yew can grow to a height of 30 feet. It is widely used in the States as an ornamental shrub in urban areas similar to where the bears were found.All species of yew contain the alkaloid compound "taxine" that is highly toxic to most animals and humans if ingested. Some animals, such as white-tailed deer, are more resistant to effects of taxine because they possess mechanisms to prevent the absorption of the toxin into their system.Taxine is found in all parts of the yew with seeds containing the highest concentrations of the toxin. The yew is toxic year-round however, toxin levels increase during the winter months."Black bear feeding activity increases just before hibernation as they accumulate fat that will sustain them through the winter," explained Game Commission bear biologist Mark Ternent.Poisoning from the plant can cause sudden death in animals due to cardiac arrhythmia within one to three hours after being ingested. Several yew shrubs were in proximity to the dead bears."This is the first case of black bear deaths attributable to yew intoxication that I have heard of," said Game Commission wildlife veterinarian Justin Brown."The denning and hibernation of the sow and her cubs were likely imminent and bear cubs will follow the lead of the sow when foraging for food. Wildlife conservation officers and agency biologists encounter bears that have died from unusual causes every year, but this may be a first," said Ternent. "This unfortunate occurrence was extremely rare and one we hope will not be repeated."