Desert bat
| Desert bat | ||||||||||||
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Desert bat ( Antrozous pallidus ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Antrozous | ||||||||||||
| H. Allen , 1862 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Antrozous pallidus | ||||||||||||
| ( LeConte , 1856) |
The pallid bat ( Antrozous pallidus ) is a species of bat from the family of Myotis bats (Vespertilionidae), which in North America is based. The generic name Antrozous refers to the Greek antron (= "cave") and zoos (= "life in"). The species name pallidus refers to the light fur color of the animals.
description
The desert bat is a large bat weighing up to 28.9 g. It differs from other North American smooth noses in its large ears and eyes, as well as its light fur. Plecotus townsendii and Plecotus phyllotis also have large ears, but these are connected in the middle, while the ears of the desert bat are separated. The desert bat occurs in Mexico sympatric with another long-eared bat species ( Macrotus waterhousii ), but in contrast to the desert bat , this has a nasal blade and thus belongs to the family of leaf noses .
Way of life
The desert bat is a typical desert species. Your urine is highly concentrated to minimize water loss. During the day, the animals sleep in colonies of up to 200 individuals in crevices and buildings. Tadarida brasiliensis and Myotis yumanensis are also found in the desert bat roosts . The crevices are selected so that they have a temperature of around 30 ° C, depending on the season. At night, the animals sometimes gather in roosts outside of the daytime sleeping area, where they eat their prey or where they become frozen for a short time to save energy. The animals hang close to one another and communicate by social calls. In winter the desert bat hibernates individually or in small groups , but isolated animals have been caught at an outside temperature of 2 ° C. The desert bat is one of 10 bat species that have been described to walk on all fours. The bat moves forward on the wrists and feet. The desert bat is considered to be the most agile and versatile of the known walking species. In flight, the desert bat reaches a speed of up to 14.3 km / h with 10 to 11 wing beats per second. Echolocation is the main sense in orientation, but sight and smell also play an important role. Echolocation calls are emitted through the mouth in flight and when moving on the ground. Well-known predators of the desert bats include snakes , veiled owls and other owls as well as the great spotted falcon and the corner-tailed caterpillar ( Accipiter striatus ).
nutrition
The desert bat is an insect eater that feeds on large arthropods that it catches on the ground or in flight at a height of a few meters. The rugged skull of the desert bat is primarily designed to crack beetles with hard shell. Swarms of small flying insects are mostly ignored. The prey scheme includes scorpions , crickets , roller spiders , beetles , grasshoppers , praying mantises and hawks . There are also individual reports that the desert bat eats toad lizards and pocket mice . Since the prey is mostly caught from the desert floor, it is assumed that the light fur color of the animals protects them from predators.
Reproduction
Mating takes place on horizontal surfaces between October and December, with the animals hanging upside down. The female stores the sperm in the sex tract until ovulation occurs in spring. Pregnancy lasts about 9 weeks, although the time of birth seems to be determined by the local climate. Between May and June the females give birth to one to three pups hanging upright. The newborns are caught with the help of the tail membrane. The young are born without hair, with closed eyes and ears and are therefore nestled . They are carried by the mother on the teats. Hearing begins after about 6 days; the eyes open after 2–5 days. After 18 days the animals are completely hairy, the fur of young animals being darker than that of adult bats. After 4–5 weeks the young animals begin their first attempts at flight, after 8 weeks they reach the weight of a fully grown animal. During this time, the young animals are also weaned from their mother. The females return to the same colony each year to give birth to their young. This preference is presumably passed on to the young female animals.
communication
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In addition to echo location, the desert bat uses a variety of different sounds:
- Alarm calls ("irritation buzzes") are loud (133 dB at a distance of 10 cm) and lie in the range between 4 and 20 kHz that can be heard by humans. They are expelled when the animals are disturbed or are in danger. They probably serve to warn conspecifics. Females also make these sounds when weaning their young.
- Squabble notes are between 5 and 15 kHz and are emitted when the animals look for their place within the group.
- Social calls (English "Directive calls") consist of up to six loud (100 dB at a distance of 10 cm) calls between 5 and 30 kHz. They serve for mutual orientation when looking for conspecifics.
- Satisfaction sounds (English "Notes of contentment") are emitted when there is intentional physical contact between the individuals.
- Wailing sounds (English "planitive notes") are loud, long screams in the audible range between 10 and 15 kHz, which are emitted by bats in pain.
- Isolation calls are emitted by young animals when they are separated from their mother. They help the female to find her cubs left behind in the colony during the feeding flights.
Special pairing and recruitment calls are not known.
distribution and habitat
The distribution of the desert bat ranges from Mexico to California to British Columbia and Cuba . Their population is classified by the IUCN as stable and non-threatened thanks to their widespread distribution and likely large populations.
literature
- JW Hermanson, TJ O'Shae: Antrozous pallidus , Mammalian Species , No. 213 (1983): pp. 1-8
Individual evidence
- ^ CL Dietz (1973) Bat walking behavior. Journal of Mammology, 54: pp. 790-792
- ^ RT Orr (1954) Natural history of the pallid bat, Antrozous pallidus. Proceedings of the California Academy of Science, 28: pp. 165-264
- ↑ Antrozous pallidus in the IUCN Red List of Threatened Species .
