What are U(V) looking at?

Animals that can see things we can’t…

Image by (Platelicker)

For a long time, this was the only known electromagnetic radiation as all the others are invisible to us, but in fact, it’s only a small part of the electromagnetic spectrum. The spectrum also includes household names such as radio waves and microwaves.

You’ll also have heard of Ultra-Violet (UV), known for helping us catch a tan or causing cancer. It also helps our body create vitamin D and serotonin (our happy chemical) so it’s not all bad. UV accounts for about 10% of the Sun’s radiation, and some animals have learnt to harness it by “seeing” in UV. Something completely invisible to us! The GIF above shows UV on the left, and what we see on the right.

Why evolve this special power?

It’s all about the types of things that reflect/absorb UV and why that would be useful for animals to see. For instance, flowers often have distinctive UV colour patterns making them easier to spot… bingo! If you can see in UV you’ll easily be able to find that delicious nectar in the flower, hence bees & butterflies can see in UV. (Apparently, flowers look more magnificent in bee vision).

Urine also leaves visible traces in UV, hence some hawks see in UV allowing them to easily spot trails of it on the ground and find small prey.

The frozen Arctic lands reflect ~90% of UV (compared to only a few % elsewhere). So, reindeer adapted to see the world in UV. Urine (that can signify a predator or a potential mate) and some of their food sources (lichen) absorb UV making them appear black in contrast to the UV-reflecting snow and therefore easy to spot.

The world around us is really amazing, it’s a shame we cannot sense all the spectrum but through cameras and technology, we are able to start to see what the animals around us are able to observe.

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