Bats form the order Chiroptera, a widely distributed group consisting of more than 1,100 species They are known to be nocturnal and gregarious, as well as sleeping on your stomach in the darkest places. For this reason, they have given rise to a whole series of terrifying myths. In addition, they stand out for being the only winged mammals and, therefore, the only ones capable of flying.
Due to the lifestyle of these animals, their sexual behavior has been less studied than that of other animals. However, little by little many curiosities about some species are becoming known, such as their elaborate courtships, their separation by sex and the collaboration between mothers during breeding. Do you want to know more about these interesting animals? Don't miss this article on how bats reproduce
Reproduction of bats
Reproduction of bats is very complex and different in each species In addition, it can vary within the same species depending on environmental conditions, the size of the colonies and the available resources. Therefore, we are going to try to explain how bats reproduce in the simplest way possible.
All types of bats exhibit sexual reproduction This means that there are males and females that must copulate in order to have offspring. In some species, males and females are very similar, although it is more common for them to be larger and more corpulent. This is because it is the females who select the males and, normally, those chosen are the strongest and most competitive.
As occurs in many mammals, Most bats are polygamous, that is, a male reproduces with several females. However, there are also many species that practice polyandry or, what is the same, that the same female reproduces with several males. In these cases, both males and females have sexual relations with several individuals throughout the same reproductive season. Monogamy has also been documented in a very small number of species.
Is the bat oviparous or viviparous?
When spring comes, the females give birth to their young, that is, they are viviparous animals The young of bats are born fully developed, since they are also placental mammals. However, need their mother's care during their juvenile stage. Therefore, they stay with her for a while and feed on the milk they suck from her breasts.
Bat Breeding Season
As with the type of reproduction, the breeding season depends on each species and also on the place where they live.
In parts of the world where there are seasons, females usually have their young in spring or summer Although they spend several months breeding, in many species they become receptive shortly after giving birth, so that they mate in summer. Thus, they store the sperm of the males until the following spring. It is also very common for mating to occur in autumn or during hibernation, when mixed colonies are formed.
Many species of bats are among the animals that migrate. In these cases, it is common for them to mate in the settlements they establish along the journey, before or after winter. In other species, mating has been documented to occur in the spring and breeding in the summer.
As for the reproduction of tropical bats, it takes place throughout the year, since they have no limitations of temperature. For this reason, there are usually several calvings throughout the year.
Bat Courtship
To understand how bats reproduce, it is essential to know their courtship. It is a series of rituals performed by males to attract and access females. Some of them are among the most curious courtship rituals in animals.
In solitary males, courtship begins with defense of territoryIt is a series of flights that indicate to other males that said territory and the females that nest in it are already occupied. It is usually accompanied by the emission of a series of characteristic ultrasounds that are known as "territory calls". In addition, in some species, it has been documented how males strike with their wings, bite and grab each other, even falling to the ground.
In this way, the males show the females that they are the fittest. But it is not usually enough to have a territory, they also perform other types of flights and courtship calls, in addition to emitting strong odors that attract females. In this way, they ensure that they go to the mating shelters and/or copulate with them. Although some females are monogamous, more often than not they go to multiple roosts and mate with multiple males.
As we mentioned before, in some species the males form aggregations, such as the "leks" of the African fruit bat (Hypsignathus monstrosus). Many individuals gather in caves or hollow trees, where each male tries to displace the rest and struggles to position himself in the area higher Thus, those who get better positions have more chances of mating when the females arrive. Something similar occurs in the Indian flying fox (Pteropus giganteus), a species in which the most dominant males hang from the highest part of the trees.
Bat Nests
In most bat species, females congregate when the breeding season arrives. They do it in certain places that they choose according to microclimatic conditions, such as temperature, humidity and proximity to food. Although some groups occasionally and change, these females usually share the same matrilineal lineage Therefore, they remain together in the nest for several months, hanging upside down and caring for their young.
The place chosen for breeding is usually natural caves, holes in trees, demolished buildings, cavities in roofs, attics, old nests of other animals, etc. Nests built by males have been documented in very few species. This is the case of Lophostoma silvicolum, which makes its nests in trees, digging in active termite mounds. Other males, such as Cynopt and rus sphinx, build tents with large leaves.
During the breeding season, there are also other types of refuges where the males stay They are usually made up of a single male and several females. Its purpose is mating, so that, after copulation, the females go to the maternity colonies, where they give birth and care for their young. In other species, mating occurs in the hibernation shelter.
Finally, in very few bats, the males form aggregations known as “leks”. There, they wait for the females, who come to these places to select the most suitable male and mate with him. But how do females choose males? Normally, through different types of courtship that we are going to see now.
How are bats born?
After mating, females store sperm, which usually belongs to several males. When the ideal environmental conditions arrive, fertilization occurs and gestation begins.
Bat pregnancy usually lasts between 1 and 2 months. Later, the calving takes place, an event that always occurs in the maternity colonies and, normally, during the day. The female stands head up and forms a kind of cradle with her wings and tailThus, pick up the hatchlings, which come out little by little.
After delivery, which lasts about 15-30 minutes, the female licks and cleans the young. These weigh around 10-20% of the weight of her mother. In the smallest species, they can weigh less than 2 grams. Normally, the litter is made up of between 2 and 4 pups that are daughters of different males, since, remember, the sperm usually belongs to several individuals.
Bat young feed on their mother's milk and stay with them for months and even years in some species. It is also common for females to cooperate in caring for the young, protecting the juveniles together, keeping each other warm and even caring for the young of other females, as has been observed in Nycticeius humeralis and Phyllostomus hastatus. This occurs in those colonies of females that are stable and share a relationship.
Only in monogamous bats, such as V ampyrum spectrum and Lavia frons, males perform parental care and feed the female during mating. breeding. It is very similar to what happens in typical bird reproduction.
