WTF Fun Fact 13161 – Bats Give Birth Upside Down

Female bats give birth upside down and catch the baby in their wings.

Interesting facts about bats

We know bats sleep upside down, but we weren’t aware they did much else that way. And you can chalk that up to our clear lack of knowledge about anything bat-related. But thanks to Montana’s Public Radio station (cited below) and their show “Field Notes,” which is produced by the Montana Natural History Center, we now know a lot more!

For example, did you know bats only breed when it’s rainy? Or share the responsibility for nursing baby bats among colony members? Or that the “colony” is actually called a “harem”?!

It turns out that female bats are only fertile during the wet seasons. That’s January or February in the Southern Hemisphere, or March or April in the Northern Hemisphere.

They divide themselves up into harems, territorial groups with one central male bat. However, that bat doesn’t father all the bat babies. Female bats in the harem may mate with other male “harem leaders.” Interestingly, the bat experts note that “it’s very unlikely that they will mate with a non-harem male.” So any lone bats out there are out of luck.

Apparently, the smaller the bat is, the more likely he is to be successful in reproducing. That’s because the males don’t simply go around and mate with harem members at will – they have to work for it. Males have to attract females with a display of flying and hovering prowess. Big bats can’t hover as well.

According to Field Notes, “Smaller males are more successful fathers because they can maneuver more nimbly in the air. Not only can they hover well and display themselves to females, they can maneuver well during actual mating, which happens – you guessed it – upside down.”

How do bats give birth upside down?

Ok, so that’s already more upside-down time than we had imagined.

But what about birth?

Females have only one baby per pregnancy, and those babies gestate for three months. When they are ready to give birth, the mother bat hangs upside down by her feet (occasionally grasping a ceiling or branch with her hands as well). This might sound like a lot of work, but when a bat’s feet grasp something, they are actually at rest (unlike ours). So it would take more energy to be in any other position.

Eventually, the baby bat emerges feet-first and they can even grasp their mother’s fur to pull themselves out. That’s helpful!

The mother then uses her wings to ensure the baby doesn’t fall from whatever she’s hanging from.

Not only do mothers nurse babies upside down, but they even take them on hunting trips when they’re not in baby bat daycare (or small groups of young called “creches”).

The mother bats nurse their young until two weeks before they’re weaned. At this point, they may let other mother bats nurse their babies.

And a final interesting fact – female bats are favored by mothers and more likely to survive.  WTF fun facts

Source: “Bat Moms Do A Lot Of Hanging About” — Montana Public Radio

WTF Fun Fact 12590 – The Spider That Eats Its Mother

It may sound like just another day at the office for some mothers used to giving their all to their children, but some spider moms really do make the ultimate sacrifice for their young.

It’s called matriphagy, the act of eating one’s mother, and it’s rare. But it happens in a spider species called Stegodyphus lineatus.

These spiders only have one group of babies throughout their lives. And when these spider babies are born, they are entirely dependent on their mothers to regurgitate food and feed it to them so they can grow up.

And what does she get in return?

Well, to be fair, the moms don’t put up a fight. After about two weeks of motherhood, they allow their children to consume them, leaving behind only an exoskeleton.

The spiders are native to Israel, and research into matriphagy in this species showed another interesting thing. Females that had given birth actually started to digest their own tissues before their gruesome deaths. Now, that might be a sign that the species just wasn’t designed to survive motherhood. However, Dr. Mor Salomon, a postdoctoral fellow in entomology at the Robert H. Smith Faculty of Agriculture, Food & Environment of the Hebrew University of Jerusalem, also found that the ovaries and the heart were the last organs to degenerate.

It also seems that spider mothers know their time is limited because they stop maintaining their web after their babies begin to grow.

Please don’t assume that females who don’t give birth have it any easier. They also tend to sacrifice themselves when a member of the colony has babies. Researchers are still looking into whether this is conditioned behavior or part of the species’ biology. – WTF fun facts

Source: “Arachnid Matriphagy: These Spider Mothers Literally Die for Their Young” — Entomology Today