My research led me to making some fun discoveries in my own neighborhood. While sitting outside at dusk on a summer evening, I noticed that the barn swallows disappeared a few minutes before the bats came out. Swooping, diving barn swallows fill the same niche as the bats, but they are the day shift workers! Niche is an important ecological concept that comes up naturally in talking about nocturnal and diurnal animals, so I made sure to include it in the text.
Reading level: Written for fourth grade, but the use of crepuscular causes readability formulas to short-circuit. Which is why I view reading level formulas with some skepticism!
To find a formatted version of this text with activities to support science and reading skills, click here: Animal Adaptations Article and Activities.
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If you spend time observing animals, you may notice that different animals can be spotted at different times. Robins and blue jays like to fly during the day. Bats and owls can be seen at night. Why do some animals prefer daylight hours, while others prefer darkness?
Diurnal: Daylight Creatures
Creatures that are active during the day are called diurnal. These animals have special adaptations to help them do well in daylight hours. Many of them have good eyesight in bright light, such as peregrine falcons, dragonflies, and red-tailed hawks. Some diurnal creatures show warning coloration to scare off predators, like bumblebees.
Nocturnal: Night Creatures
Some animals are active at night. These animals are called nocturnal. Nocturnal animals also have special adaptations to help them find food at night. Bats use echolocation to find food in the dark. Owls can see well in the dark, and so can cats.
Many nocturnal creatures have very large eyes. Big eyes help them to see in low light. Some nocturnal animals, like red foxes, also have excellent hearing.
Crepuscular Creatures
Many creatures are most active in the morning and the evening. These creatures are called crepuscular. They aren’t diurnal, but they aren’t nocturnal either.
Many animals that are sometimes called nocturnal are actually crepuscular. For example, white-tailed deer are crepuscular. People can usually see them early in the morning or at dusk in the evening. Cottontail rabbits are also crepuscular. Fireflies, the special insects that light up to attract mates, are crepuscular as well.
It’s All About Niche
Why are some animals diurnal, and others are nocturnal or crepuscular? Different animals have different niches, or roles in ecosystems. No matter when they are active, all animals seek to find food and raise their young. For example, barn swallows are small birds that love open meadows and farmlands. They swoop around during the day, catching and eating insects.
Little brown bats live in the same habitat as the barn swallow. They also swoop around to catch and eat insects. But barn swallows and brown bats don’t compete. Why not? Barn swallows fly by day, while brown bats fly by night. Each has its own niche in the ecosystem.
There are many examples of day and night animals sharing a niche. Bees are well-known pollinators during the day. At night, moths take over, and pollinate large, fragrant flowers. Another example of niche sharing can be seen with owls and hawks. Hawks hunt rodents during the day, while owls hunt at night.
For many animals, being adapted to be active during the day, night, or twilight can help them to find food and avoid competition. Try observing some animals around your house. What do you notice?
by Emily Kissner
©2024. Permission granted for single classroom use. This text may not be resold or included in any products offered for sale.
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