Nocturnality

Temporal specialists, according to the chronobiology creatures that have evolved in the course of their evolution in their lifestyles to mainly night, crepuscular or diurnal organisms. Not only animals but also plants ( Flower Linnaeus ) and even protozoa ( Gonyaulax ) have differentiated the time of day in their development.

In plants, many day-specific forms can be observed especially in flowering. For example, the Queen of the Night blooms often only one night to let pollinate of bats.

Especially in land animals, it is primarily during the day or come during the evolution to a significant specialization in activity over night. For organisms living in water that is less the case as water buffers temperature differences. Originally most land animals were probably mainly nocturnal, as they had to protect themselves against desiccation, solar radiation and high temperatures.

The most primitive insects ( stoneflies ) and vertebrates ( amphibians) are even now mainly active at night.

The apparent evolutionary later protection through a tough cuticle or horny layer enabled the occupation attractive niches by insects and reptiles. Hand in hand with this development was an improvement to the body color and visual communication. Nocturnal animals use the visual system to a lesser extent than diurnal animals. In general, the olfactory ( moths, most mammals), and auditory sensory ( crickets, owls, bats ) are far better developed in nocturnal animals.

The mammals specialized originally referred to a nightlife, and only some diurnal groups such as the primates developed color vision. Nocturnal animals usually have pronounced camouflage colors, which allow them during the rest phase on the day, to hide from predators. If they carry a warning color, is usually black and white (eg skunks ).

" Perfect Day" and "Night Animals " are global terms, designating the period of their preferred activity time. In addition, there are also animals that are primarily active during twilight. A good example of this is trout - visual hunters still be able to benefit from the nocturnal insects at dusk.

Small mammals such as voles, shrews, but also guinea pigs are often not unequivocally classified as either day or night animal because they have to eat through a high energy consumption and / or low-calorific food on both days halves. In these animals, activity is located in the ultradian rhythm in particular. Are small mammals forced to lay their activity either on the day or night, they must find ways to take to save energy ( torpor ) or high caloric feed as that.

It is also observed that there is a temporary niche shifts when the food supply requires the. For example, bats hunt in the spring and fall during the day, when the nights are too cold for a sufficient insect populations.

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