I could smell the electricity in the air this morning, and my tummy had been warning me of the approaching storm since yesterday evening. I wanted to go down to the woods before the storm started to see what the animals and birds were making of it all. So, Blaze and I took our usual route down the track, Blaze running back and for after her ball. The woods were eerily quiet, the creatures knew what was coming. There was a distant roll of thunder and a few birds squawked and cried before becoming silent again. In the distance a lone farm dog barked.
We headed back home as the occasional huge, heavy drops of rain plopped out of the sky and landed on the track, sending tiny clouds of dust into the air. Blaze was nervy. She wanted to walk ahead – but not too far. She was on high alert and I expect she could sense the electricity; smell the petrichor aroma – that instantly recognisable smell we experience when it rains; and hear the storm as it rumbled around the valley.
We passed the cows in the field alongside the track, and many of them were laying down; the swallows were flying low; and everything seemed to be pushed down towards the earth by the changing air pressure. My tummy continued to rumble just like the distant storm and my husband complained of the pressure in his head.
Each time there was a flash of lightning, I counted the seconds until the clap of thunder came. The storm was getting nearer and fortunately we made it into the house before the rains came.
Here’s a video and a poster about thunderstorms:
By lunchtime it was so dark we couldn’t see to read, and I was feeling very, very unwell. Blaze and I sat on the bed and watched the blue cracks of lightning shoot across the sky. I also faffed about on the internet in between the power cuts, researching what I could about how animals “know” what the weather will be like.
Animals have often been attributed with supernatural abilities; ESP; or in the case of Paul the Octupus – an ability to predict World Cup football match outcomes. Our folklore is full of tales of birds and weather prediction:
- Hawks flying high means a clear sky. When they fly low, prepare for a blow.
- Geese fly higher in fair weather than in foul.
- When seagulls fly inland, expect a storm.
Air pressure certainly does affect birds. Swallows, for instance, have sensitive ears; when the barometric pressure drops, they fly as close to the ground as possible, where air density is greatest. Low-flying birds are signs of rain; flying high indicates fair weather.
Studies in the past few years have shown that birds may also be responding to infrasound – those sound waves that humans can’t hear. It appears that some birds may hear the infrasound noise of a distant tornado as the soundwaves travel through the ground. This acts as an early warning signal and enables the birds to fly to safety long before the tornado arrives.
It is likely that animals “know” about approaching weather because of their incredible senses. I don’t think for one moment they can see into the future in a magical way. They can predict the future, but scientifically through using their eyes, ears, and noses. Different animals have different numbers of senses – humans have eight senses, whereas other animals have some extras like magnetoreception, and electroception. As well as that, the senses that other animals share with us can work outside of the ranges humans are used to.
I’ll describe one sense in detail to demonstrate how this works, and I’ll briefly explore some of the other senses.
Bears are thought to have the most sensitive smell. This is essential for helping them survive. Bears often forage for food, and the ability to smell something edible 20 miles away in the case of the Black Bear, or through 1 metre of ice in the case of the Grizzly, means they can conserve their energy and head straight to the food source instead of searching around.
Here’s a diagram showing how different animal’s sense of smell compares:
So how does it work? What makes certain animals specialist sniffers?
There are several things going on. Let’s take Blaze, my dog and compare her to me:
Her nose is a different shape to mine for a start. I breathe in and out through the same airways inside my nose. If I take a big sniff of something and then exhale, incoming scent is pushed out with the exhaled air. To get a really good smell of something, I have to keep sniffing it without breathing out at the same time – try it, have a good sniff of something nearby.
A dog’s nose is more sophisticated in the way it functions. Blaze’s nostrils, unlike mine, can move independently, helping her locate where scents are coming from. When I throw her ball and she doesn’t see it land, her nose goes to work – and I can see her nostrils quivering and sniffing in lots of different directions until she locates the path of the scent. This quivering, pushes the scent further up her nose so it doesn’t mix with new smells coming in – it helps her stayed focused.
Take a look at the photo of Blaze’s nose below or at your own dog or cat’s nose if you have one. When Blaze breathes out, the exhaled air leaves through the slits in the side of her nose, and the swirl of wind created by this exhalation helps send more new scents into her nose.
Smell Receptor Cells
The average dog has around 220 million smell receptor cells – some breeds have many more. A human has only 5 million scent receptor cells. A dog not only has more cells than a person, it has more types of cells. This enables a dog to detect a greater variety of smells.
A dog has another organ for smelling, absent in a human, called the vomeronasal organ.
It’s not just our sense organs that are important in smelling, tasting and hearing the world. The way our brains process this sensory information is important too. Brains interpret and prioritise the messages that have come via the sense organs. The brain also tells the body how to react. So, Blaze’s brain is clearly working differently to mine – she needs to be able to process information that is important for dogs – things like finding food and a mate. My brain processes differently because I’m a human. I need to find food, just like Blaze but I tend to do it with my eyes not my nose. I may wish to find a mate, but again I don’t do it by sniffing them! Of course, there is a huge amount of diversity within the same species too.
Most mammals are dichromats and get their colour vision from two kinds of visual pigment. But humans and some other primates have trichromatic colour vision and can see a greater variety of colour.
Humans can see only a tiny part of the electromagnetic spectrum. Some creatures can see wavelengths of light that are outside of human vision.
It’s difficult to imagine that some animals see and hear things that we don’t. Some owls can see ultraviolet light. Their prey are voles, which leave urine trails behind them that show up in UV light. Elephants can communicate over long distances using infrasound waves traveling through the ground and whales communicate over vast distances in the ocean, while we wander about on land, oblivious to the cacophony below the waves.
People have different experiences of sensory information too. Some autistic people may be able to hear conversations in a distant room or spot the difference between two almost identical objects. Children have sensory abilities that are lost as they become adults. Babies are born with an ability to differentiate between individual faces on monkeys and humans, but by the time they get to around nine months, a process called perceptual narrowing takes place in their developing brain and they can only distinguish the human faces.
Here’s a couple of fun activities to try:
Which is the odd one out?
When adults look at the images of a snail (above) they typically say that glossy snail A and and glossy snail B are the most similar. The matte-looking snail C seems to be the odd one out. But a baby can tell that snail B and snail C are actually more similar.
Have a listen to these sounds. Depending on your age, you may hear one or more sounds from these recordings of different frequencies.
As we discover more about how our own and other animals’ senses work, it’s not surprising that some animals appear to predict the weather. Our human noses aren’t as good at detecting smell as a bear, for example but we don’t need to be. We can hunt and gather food more readily. But we are particularly good at smelling petrichor – the smell released from the earth when it rains. We can smell it in tiny concentrations of five parts per trillion. Being able to smell rain had an advantage for our ancestors that relied on following the rains for their survival.
Of course, once you appreciate the extra senses that animals have – like the birds ability to migrate accurately between its homes using an internal compass; or the sharks ability to detect its prey using electricity, its no wonder that creatures may be seen as magical or possessing special powers. I imagine that humans who have sensory abilities outside of the standard could be viewed differently too – as magical, supernatural or mentally ill, perhaps? People often look to religion and make believe to explain science they haven’t yet been able to understand.
I think it is important to remember that just because I don’t see something like a bird does, doesn’t mean that the bird can’t see it; or is making it up; or is magic.
Storms fill me with the wonder of the natural world and the power of nature is breath-taking. Learning about how the world works and how all the different creatures experience it, is awe-inspiring.
I distracted myself through the thunderstorm this afternoon by writing this blog. All of a sudden, a small tortoiseshell butterfly flew frantically into my face and fluttered around my patterned blouse before crashing against the closed window repeatedly, as if it was in a mad rush to escape. It must have quietly been sharing my room during the storm and it “knew” it was over and it was ready to go outside again. I opened the window to release it and the birds were singing a different song to this morning – declaring to the world that it was safe to come out. We headed off to the local gardens for some fresh air and enjoyed the buzzing of the busy insects catching up on the hours of nectar they had missed.