8 Animals That Are Evolving Quickly

a brown lipped snail moving along a bright green leaf

Papa Lima Whiskey 2 / Wikimedia Commons / CC BY-SA 3.0

Whether due to climate change or other environmental conditions, animals are constantly evolving to better survive. Many think of animal evolution as something that takes place over hundreds of thousands or even millions of years, but this isn't the case for some particularly resilient species. From the banded snail to the pink salmon, here are some animals that have adapted quickly.

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Tawny Owls

Tawny owl on a branch of a large tree trunk with green leaves

Mike Pearce / Getty Images

An animal showing clear indications of rapid evolution due to climate change is the tawny owl, a species common in Europe. The tawny owl typically has two color variations, a brownish color and a lighter gray color. The gray-feathered owls are more common in colder areas, since their lighter hue helps them stay camouflaged in the snow. However, researchers in Finland discovered an increase the number of brown owls in their area. The change in color, scientists found, is due to warming winters in Finland. The darker colored plumage makes it easier for the owls to blend in with their less snow-covered environment.

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Hybrid Mice

brown wood mouse in an underground cave

DamianKuzdak / Getty Images

Mice have devised a new way to outwit humans. A study of house mice across Europe found that when two different species of mice bred, their offspring became resistant to typical household poisons. The resistance gene, which was only found in one of the two species, was passed to the baby mice. These mice do not usually intermingle — they came together due to the expansion of agriculture — and the adaptation occurred because of the introduction of insecticides.

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Green Lizards

green lizard on a broken brown tree branch

Daniela Duncan / Getty Images

As the invasive brown lizard started moving in on the turf of native green lizards, the latter started to adapt by moving farther up the trees. As they did, their bodies had to adjust. In a short amount of time (about 15 years), researchers in the College of Natural Sciences at the University of Texas at Austin say the green lizard grew bigger pads on its toes. It also developed stickier scales to help it grip. So if you're searching for lizards, look up in the trees.

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bedbug on a green leaf protecting its eggs

Eduardo Angarita Muñoz  / Getty Images

In the case of bedbugs, evolution is good for animals, but bad for humans. Since humans have used an abundance of chemicals to keep bedbugs at bay, bedbugs have developed thicker shells and tougher nerve endings. Ohio State University has been a leader in the study of bedbugs, and scientists there say that most over-the-counter products available to consumers don't work that well on these pesky insects.

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Peppered Moths

Peppered moth on lichen covered bark

 Ian_Redding / Getty Images

The peppered moth is a well documented example of animal evolution. Before the 1800s, the peppered moth had light, mottled wings. The dark, solid-colored version, like the one below, at one time made up only a small fraction of the population. After the Industrial Revolution, the population numbers changed drastically as the darker moths became far more common. Scientists discovered that that the change was caused by a gene mutation. Surfaces that were once light were darkened by pollution, and the moth adapted to survive.

specimen of a solid black peppered moth
Chiswick Chap / Wikimedia Commons / CC BY-SA 3.0 

Improved conditions, including a reduction in air pollution in the moth’s environment, has resulted in less black soot and more colorful lichen. The moth is beginning to lighten in color and regain its mottled appearance to blend into its new, healthier environment.

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Banded Snails

banded snail in crawling through green plants

Johner Images / Getty Images

In Europe, banded or grove snails typically have light yellow, pink, or darker brown colored shells. Researchers have discovered that in urban areas, the shell color of snails has become lighter. As a result of higher temperatures caused by global warming, in larger cities there are more snails with yellow shells. The lighter shell color is an evolutionary response that keeps the snail cooler.

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Italian Wall Lizards

bright green and brown Italian wall lizard on a large black stone

Dora Caprai / EyeEm / Getty Images

Introduced to the island of Pod Mrčaru for experimental purposes in the 1970s, the Italian wall lizard has undergone an impressive physical transformation due to its dietary changes. In their island setting, the lizards switched from a diet composed primarily of insects to mostly plants. Scientists discovered that the change in diet caused the lizards to develop larger heads, cecal valves to improve digestion, and wider teeth.

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Pink Salmon

pink salmon in shallow water at Prince William Sound

Karen Kasmauski / Getty Images

Climate change is affecting all living things, including the pink salmon. These fish are migrating a couple of weeks earlier than they did 40 years ago. Researchers closely studied 17 generations of salmon populations in Alaska and found that this change coincided with genetic changes in the offspring. The adaptation occurred quickly, and the salmon population overall remained stable, evidence of the resilience of the pink salmon to changes in their environment.