Have you contemplated whether your pets see their lives a being as short as you do? Did you ever wonder why it is so difficult to successfully swat a fly? Why do they always know when you are going to strike? It turns out that the answers to these questions are hidden in the differences in the way different species of animals “see” the world.
Kevin Healy, a Phd student at Trinity College in Dublin, Ireland, wondered the same things. His research in the recent edition of Animal Behavior suggests that animals perceive the length of their lives as no shorter than our own. Why? The experience of time is subjective, not objective, so the individual perception is the basis for the way we look at the length of things. However there is an objective measure of visual perception.
The critical flicker fusion (CFF) is the lowest frequency of a flickering light that is perceived to be a constant light. Some refer to this as the refresh time necessary to process visual information. For humans, this period of CFF is 60Hz or 60 times a second. This is the same refresh time for the image on a TV screen so we see it as a constant image rather than a series of images that are occurring at 60 images per second.
Dogs have a CFF of 80Hz. When they watch TV is like watching a group of rapidly changing still photographs. This is why most dogs do not enjoy watching TV. This may be bad news for the DOGTV people.
Flies have a CFF of 250Hz. When you swat at them they perceive the flyswatter as moving in extreme slow notion. They easily escape our swat. Now you know why they win most of the time. But this could also mean they perceive their lives moving in the same slow motion. Their perception of their lives could be longer than our perception.
Mr. Healy was intrigued by this possibility. He suspected that the determination of an animal’s CFF was it size and metabolic rate. The smaller the animal the less distance was required for signals to reach the brain. A higher metabolic rate meant that there was more energy to process this neural information.
It is known that the smaller the animal the higher the metabolic rate. This means that all body functions occur faster as the size of the animal decreases. This also typically correlates with life span. Animals with lower metabolic rates tend to live longer than those with higher metabolic rates. Mr. Healy compared size, metabolic rate and CFF.
He found that there is a correlation between animal size, metabolic rate and CFF. He concluded that evolution favors animals to view their world in the slowest possible time.
Our perception of the life span of other species is based on our own perception of our life span. Other species don’t see it the same way. From a fly’s perspective, their 15 to 30 days is just as long as our 75 years. Your dog and cat feel the same way about their 15-20 years.
Dr. Ken Tudor