Scientists use whale earwax to study pollutants and stress

Whale

Leanne Jenkins----The ear wax of whales has been found to offer good information on how a live animal is able to handle stress and pollutants, scientists have learned.

Because it's hard to study chemical exposure that is time-specific for animals, this newest finding is helpful, as the blue whale offers the path to learning more about how mammals of the sea, who are the world's largest inhabitant, manage stress.

Like other living creatures, the whale's life is filled with its own types of stress. The team of environmental scientists who have made the exciting discovery of how ear wax of whales can offer information on how the whale handles stress, studied a whale that had been killed by a ship off the California Coast. It was found to have had contact with environmental pollutants as well. High levels of cortisol were found in the animal.

Scientists can't tell, however, by analysis of blubber when a whale was contaminated by pollutants or how long the contamination lasted. But the earwax of the whale offers better clues to how the whale has managed its environment over time.

Researchers learned that exposure to the most active or most often found pollutants appeared greater in the first year of a whale's life, likely that occurred from the whale mother's womb and during the feeding of the infant whale. Mercury, an element that can cause brain damage, is found at about age five to ten years. Ten years is the time the whale reaches sexual maturity, and it is also the time when stress is greater because of competition from other whales. It's also the time when cortisol, which is a stress hormone, increases.

Whales are a species in need of protection because of the risks from climate change that have increased, bringing additional stress to the lives of these animals of the sea.  They also have suffered additional stress from seismic airgun testing.   To know when stresses most occur is helpful to scientists who want to expand the lifetime of the whale and preserve the lives of those now living and into the future for those infants who encounter stress early in life. That is especially important given the fact that, according to wildlife experts, seven out of 13 great whale groups are considered endangered or vulnerable.  And chronic stress can create serious health problems for whales, as it does in humans.