Walk Softly – Weather-wise Wild Things

by Geoffrey Carpentier

We have been experiencing an unusually warm autumn season this year, with early November temperatures frequently climbing into the low 20s Celcius. It is both exciting and scary, as climate change continues to progress, sometimes making our weather hotter or colder, or drier or wetter. Still, this column isn’t about that. It’s about how nature’s plants and animals respond to weather events and changing environmental conditions. To be clear, flora and fauna don't actually predict the weather, but they do respond to subtle clues, like: humidity, temperature and barometric pressure changes, adjusting their behaviour or growth cycles in response.

Let’s look at a few examples to help explain this. Many years ago, when I lived in Peterborough, Chandler Robbins, the famous ornithologist and author of Birds of North America: A Guide to Field Identification, was attending a conference in town and asked me to take him out to look for owls. We had huge success, finding multiple individuals, representing several species of owls. Curiously, I had followed the exact same route the previous night and failed completely. Why? It turns out owls are highly sensitive and very specific in their response to barometric pressure. If the pressure is dropping gradually, the wind is low and the season is right, they are far more likely to call.

Plants also react dynamically to these atmospheric shifts. When weather changes threaten excessive water loss, plants will quickly adjust, by closing their stomata (i.e. the microscopic pores on their leaves) to regulate gas exchange and prevent drying out. Pinecones alter their shape, depending on humidity. When it is wet, their scales absorb moisture and tightly close, to protect the seeds inside, but when the air dries out, they expand and open, to let the wind help disperse their seeds.

I’ve written previously about how crickets ‘sing’ faster when it is warm, and how birds read wind speed, direction, and falling air pressure (which often precedes the onset of an impending storm) to safely time their migration routes. Nevertheless, did you know, ants and bees act as natural barometers, fortifying their mounds (ants) or rushing back to their hives (bees) ahead of pending rainstorms?

Spiders will often stop spinning or will even dismantle their webs when heavy rain is imminent, protecting their hard work before the first raindrop falls.

Frogs, whose skin is highly sensitive to moisture, respond to rising humidity by croaking more frequently and loudly. Even fish feel the shift – they utilize their lateral lines (highly specialized sensory organs along their flanks) to detect minute changes in hydrostatic and atmospheric pressure in the near-surface waters. Coupled with this, fish have gas-filled swim bladders which help with buoyancy. As barometric pressure drops, the gas inside the fish's swim bladder expands. To relieve this pressure, they often move deeper down the water column, where the water pressure compresses the bladder back to a more comfortable equilibrium.

Closer to home, dogs can smell the minuscule amounts of ozone produced by lightning or they can detect rising humidity, reacting long before a storm hits!

So, what about humans? Can we detect these environmental shifts as well as our wild neighbours? Many people note their joints ache when a storm approaches. When barometric pressure drops, this allows the tissues surrounding our joints to slightly expand, causing pain in sensitive individuals. These pressure drops also alter the fluid dynamics in our inner ears, which can trigger ear pain, dizziness or migraines.

So, putting this all together, animals and plants cannot predict weather, but they can sense subtle changes in environmental conditions and respond to those in highly predictable ways. We can observe what our wild neighbours do and make our own wise decisions, if we are astute enough. That said, these natural responses are short-term, since animals cannot see 14 days into the future, as our weather analysts claim to do. However, they are incredibly adept at detecting immediate changes which may cause them distress or harm, and they act accordingly. We can learn a lot from our animal friends to understand our environment and react to environmental conditions favourably.

Geoff Carpentier is a published author, expedition guide and environmental consultant. Visit Geoff on-line on LinkedIn, Facebook and Instagram.