What you need to know about a bat maternity colony

When a pair of new mothers get pregnant around the same time it can be a real bonding experience. They can share their highs and lows, their sicknesses, and their milestones as they navigate the task of childbirth. It’s truly a blessing if you’re lucky enough to have this happen to you. It seems that bats as a species share in this joy of company when giving birth to a new generation. Female bats will often gather together when pregnant and form what is known as a bat maternity colony.

What is a Bat Maternity Colony?

This is a temporary grouping of female bats that band together while pregnant to give birth and raise their young, weaning, and nursing them until they are grown enough to fend for themselves. Then once this happens, the colony breaks apart and goes their separate ways. The colony will typically consist of up to ten birthing mother bats. However, in some cases, it can be much larger, with the largest reported colony being in the region of 15 million bats.

multiple bat exclusion

When Do Bats Set Up Maternity Colonies?

While bats will set up colonies in the winter for hibernation, maternity colonies are set up during the warmer months of the year to ensure the best conditions to raise the young. Mating season for bats occurs in the early summer months allowing enough time for a bat to find a mate, impregnate them, and have the mother give birth before the warmer months of the year are through.

Little brown bat maternity colony

Why Do Bats Form Maternity Colonies?

There are several reasons why bats will form this colony, each with their benefits to the group. The most prevalent tends to be due to the harsh conditions that many bats will have to face depending on the region in question. When these bats band together, they can use each other’s body heat to remain warm even in the harshest weather.
Not only this, there is an important reason why these bats are keen to keep constant body temperature. When bats fall below the ideal temperature when pregnant, they will enter a state of Torpor which is a means of conserving energy. However, if a bat does this when pregnant this will not only slow down the development of the pup, but it will also slow milk production. So where possible, a bat will ensure ideal temperature, hence the colony.

Why Do Bats Form Maternity Colonies?

When a group of pregnant bats form a colony, they will be pregnant for between six to nine weeks. This varies depending on the  availability of food, the weather, and the species of the bat in question. Then once the baby bat is born, the mother will care for their young until they are old enough to fly on their own. This will take approximately five weeks. Once this period has elapsed, the colony will disband.

Why Do Bats Form Maternity Colonies?

A bat colony can be set up in just about any place that provides a warm dry shelter that protects bats from the elements. However, several spaces are more common than most. Here is a quick list of areas that you’ll likely find a bat maternity colony:

  • Attics
  • Caves
  • Abandoned mine
  •  shafts
  • Barns
  • Trees

How Are These Colonies Kept Safe?

Due to the vulnerable nature of the pups and indeed, the pregnant mothers, it can be rather dangerous for this colony to form at all, especially if predators catch wind of their whereabouts. So in order to keep these colonies safe, they are protected by law. These colonies ensure the population of bats remain strong and therefore, the population of pests and insects remains controlled as a result. The ecosystem is a very complex and fragile system, so it is vital that we do all we can to protect bats as a species.
Those that choose to remove bats from their colony or kill them during this birthing process will face prosecution for their efforts. So if a bat takes up residence in your home, be a good sport and wait until the end of summer when these bats will leave of their own volition.

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