Diurnal animalsPublished on October 18, 2019 - Last modified: October 24, 2019
The animals diurnal are those that are active mainly during the day. When the activity patterns of an organism occur in cycles of approximately twenty-four hours, the pattern is called circadian rhythm.
Diurnal animals, which sleep at night and are active during the day, or, conversely, nocturnal animals, which sleep during the day and are active at night, follow a circadian rhythm. Scientists believe that circadian rhythms are controlled by an internal timing mechanism called the biological clock. The exact nature of this internal timing is unknown, but different levels of hormones are believed to play a role.
Scientists generally agree that the evolution of species on Earth has proceeded in the direction of making the most of all possible niches (the specialized role of an animal in its environment). Therefore, some organisms have evolved to better adapt to the night, which is relatively darker, cooler, and more humid. Other creatures have specialized more for the day, which is lighter, warmer, and drier. In a way, then, organisms work in "shifts" to use the environment at all times. This allows a greater number of organisms to occupy the same area without excessive competition for space and food at any one time. The day shift includes animals such as humans, dogs, songbirds, elephants, squirrels, gorillas, deer, hawks, lizards, butterflies, bees, and chimpanzees. The night shift includes animals such as owls, bats, and mice.
Some animals have species both night as daytime. In the tropics, mosquitoes transmit two serious human diseases, malaria and dengue. The mosquito Aedes aegypti, which transmits dengue, is diurnal. The mosquito Anopheles, which carries malaria, is nocturnal.
The adaptations of animals to daytime activities are evidenced by the different properties of the eyes of some animals. For example, nocturnal birds like the owl generally have larger eyes than day birds like the hawk, for which more light is available. Larger eyeballs help nocturnal species get as much light as possible on the retina.
Difference between nocturnal and diurnal animals
- Nocturnal animal: Nocturnal animals are active at night.
- Daytime animal: Diurnal animals are active during the day.
- Cells in the retina
- Nocturnal animal: Nocturnal animals have few or no cone cells, but they have many rod cells in the retina, which results in good night vision.
- Daytime animal: Many diurnal animals have many cones, which results in good vision in daylight.
- Color vision
- Nocturnal animal: Almost all nocturnal vertebrates are color blind.
- Daytime animal: Many diurnal vertebrate animals they can see the colors.
- Nocturnal animal: Nocturnal animals communicate mainly through sounds.
- Daytime animal: Diurnal animals use a combination of methods, but vision may be more vital.
In general, the sense of touch and hearing is well developed in nocturnal animals than in diurnal animals.