Can a Canary be considered a sentinel for humans?

Well into the 20th century coal miners used canaries to monitor levels of Carbon monoxide gas in the mine. Their measurement was very simple … when the canary fell off it’s perch, the miners had a very short time to evacuate the mine. When the miners suspected their might be major methane gas issues, they posted a guard to literally watch the canary. The good news was it worked for the miners … not so much for the canaries!

Researching the subject of animals as sentinels gives one a new perspective on the importance of our animal kingdom.

Animal sentinels, or sentinel species, are animals used to detect risks to humans by providing advanced warning of a danger. The terms primarily apply in the context of ecological hazards rather than those from other sources. Some animals can act as sentinels because they may be more susceptible, or have greater exposure to a particular hazard than humans in the same environment. People have long observed animals for signs of impending hazards or evidence of environmental threats. Plants, and other living organisms have also been used for these purposes.

Some historical examples:

There are countless examples of environmental effects on animals that later manifested in humans. The classic example of animal sentinels is the “canary in the coal mine“.

In Minamata Bay, Japancats developed “dancing cat fever” before humans were affected, as a result of eating mercury contaminated fish. Dogs were recognized as early as 1939 to be more susceptible to tonsil cancer if they were kept in crowded urban environments. Similar studies did the same for animals exposed to tobacco smoke.

Some characteristics of the animals

Animal sentinels must have measurable responses to the hazard in question, whether that is due to the animal’s death, disappearance, or some other aspect.

For example, honey bees are susceptible to air pollution. Similarly both bats and swallows have been used to monitor pesticide contamination due to their diet of insects that may have been affected by the chemicals. By the same token, aquatic animals, or their direct predators, are used as sentinel species to monitor water pollution.

Some species may show effects of a contaminant before humans due to their size, their reproductive rate, or their increased exposure to the contaminant.

Today it is a common belief that cancers in dogs and cats have been linked to household exposures to pesticidescigarette smoke, toxic cleaning agents and other carcinogens. Some speculate that animals could provide early warning of a terrorist attack using biological or chemical agents.

From a futuristic perspective there has been a call for linkage of human and veterinary medicine in a “One Health” approach that recognizes disease occurring in the animal kingdom may indicate human health risk. This approach would involve greater information sharing between human health, veterinary clinicians and public health professionals.

So, if you have made it to the end of this article … You now know why I like talking about Animals being guardians for our health. 

1st graders healthier by using natural cleaning products

East Central Wisconsin

For 2 ½ months a substitute teacher took it upon herself to disinfect her classroom with a natural based, non toxic disinfectant, while influencing other1st grade teachers to do the same. The result, kids stopped becoming sick and classroom attendance underwent a dramatic improvement.

How in the world did this happen … Mrs. C., as previously reported in this blog (1st-grade-classroom-goes-green May, 2012) had previously experienced health improvements by cleaning her classroom with natural products. So as she moved into the role of substitute teacher, this was a natural thing to do.

In the spring of 2011 Mrs. C. retired from teaching, By the winter of 2012 she had accepted a substitute teaching position in her local community school system. After her very first week she realized she had major attendance issues in her classroom. Some days she had up to 8 students absent due to colds and flu.

Drawing on her previous experience she brought in Sol U Guard Botanical, the same natural based disinfectant she had used before. She immediately sprayed all of the surfaces in her classroom that the kids touched. Within 2 weeks her attendance started to improve.  Throwing caution to the wind she took bottles of the natural based disinfectant to each of the other 1st grade teachers and asked them to follow the same process she was using. She told me that she could tell things were happening because she could hear the squirting of the spray bottles as each classroom day ended.

The results after 2 ½ months … in the middle of February she had as many as 8 kids a day absent. By the end of April the entire 1st grade was experiencing their highest rate of attendance ever achieved, less than 1 student per week. While acknowledging that there are many factors that could be contributing to this improvement, it is the consensus of all of the 1st grade teachers that the natural based disinfectant was the main ingredient to the improvement. As one of the regular teachers commented; “our students are just not getting sick anymore”.

So how can you help … introduce me to a parent / teacher or principle that would be interested in hearing the details on how they can help improve their student attendance by being healthier.

Even our guardians need to rest …


An older, tired-looking dog wandered into my yard. I could tell from his collar and well-fed belly that he had a home and was well taken care of. He calmly came over to me, I gave him a few pats on his head; he then followed me into my house, slowly walked down the hall, curled up in the corner and fell asleep.

An hour later, he went to the door, and I let him out …

The next day he was back, greeted me in the yard, walked inside and resumed his spot in the hall again and slept for about an hour. This continued off and on for several weeks.

Curious I pinned a note to his collar: “I would like to find out who the owner of this wonderful sweet dog is and ask if you are aware that almost every afternoon your dog comes to my house for a nap.”

The next day he arrived for his nap, with a different note pinned to his collar: “He lives in a home with 6 children, 2 under the age of 3. He’s trying to catch up on his sleep … Can I come with him tomorrow?

This story 1st appeared in an email circulated wide and far .. I think it is so appropriate to be posted again as school is now in session … just a gentle reminder that it is most likely our pets get tired too!