No, Bats do not ley eggs.
Although bats fly like birds they are in fact mammals – the same as humans.
This means they give birth to live young.
Do Bats Lay Eggs Like Birds?
Birds are flying animals who have evolved over thousands of years to be masters of the sky. Bats however took a different route.
Just like us humans – bats were small rodents at the beginning of time. Unlike us though, they thought flying was better than walking and bats are now the only true flying mammal (other mammals like flying squirrels and sugar gliders can ‘float’). Even with the power of flight – they didn’t become birds – they stayed mammals. Just like dolphins swim like fish – but haven’t become fish.
Birds evolved over 100 million years before bats did (according to the current fossil record) and already dominated the skies when bats first appeared. Starting as gliders between branches, these small mammals soon learned a trick or two in the trees before acquiring full flight themselves.
However, evolving a whole new way of producing young was a step too far!
How Do Bats Produce Young?
Well, we can rule out the eggs anyway – because bats live hanging upside-down at the top of a cave! Not the best place to drop an egg from?
There are ledges in caves – but as bats don’t have nice warm feathers or a clever beak for making a nest – this makes things less likely. Also, they are mammals so don’t have the special machinery needed to produce a calcium-rich shell for their young.
So, if bats don’t lay eggs then – how do they produce their young?
Being warm-blooded mammals with a warm, cozy uterus – they grow their young inside their bodies. When they are developed enough to be born and survive out in the open – their gestation ends.
This doesn’t mean they are ready to go out hunting and fend for themselves though – they will still need mum’s care for the first few weeks until they are strong enough to fly.
Bats only usually have one pup at a time as these baby bats hang on to their mum all the time she is in the roost. Something that can be quite heavy on the feet while hanging upside-down – let alone with twins. Baby bats can be nearly 20% the mother’s weight – like a 40lb human baby who won’t let go!
What Do Baby Bats Eat?
Baby bats are 100% dependent on their mother for the whole time they are pups – so she has to supply all their food. And she wants to give them the best. A food that is easy to digest; high in fat and protein; and ‘on tap’ all the time. And the easiest way for a mammal to do this is through breast-feeding.
All mammals – including bats – produce high-quality milk to feed their young – a process called lactation. The food mum catches and eats during the night is converted into this perfect free baby food for her young.
Baby bats won’t eat insects and other foods until they can go out and catch them for themselves. Usually, around 3 weeks of age, they start flying but are often found on the floor of the cave after a failed attempt – or two. It doesn’t take them long before they master the art of flight though, and are off and about in the evenings, hunting with the colony.
Can Hawks Hunt Bats at Night Time?
Hawks hunting at night is a rare occurrence. While hawks are skilled predators, their hunting abilities are optimized for daylight hours. Bats, on the other hand, are nocturnal creatures and possess unique flight capabilities, making them challenging prey for hawks during nighttime.
Could Bats Ever Evolve To Lay Eggs?
Well, yes they could actually – although it is extremely unlikely.
There is no real reason – in evolutionary terms – for a bat to be better off producing eggs than giving birth to live young. However, if we have another asteroid impact or a series of massive volcanoes; we keep changing the climate and cutting down the rainforests; then the bats of the future won’t be living like the bats of today. And if they aren’t bats as we know them – then they may well be better off laying eggs?
It would be like a reverse evolution. They chose to produce live young way back, and they chose to fly after that. So if their food or habitat changes enough they might not need to fly anymore – and if they don’t fly – they might be able to sit around in nests looking after their eggs?
Evolution is a reactive process – so never say never!
