Our bat care network have been chatting a bit on our facebook page about motherhood in bats, as the birth of P-Diddy (our first baby born in captivity) 17 days ago has given us all a bit of a reason to take an interest in the subject… Motherhood and reproduction is just one more way in which bats seem to captivate and fascinate.
Aside from the delayed fertilisation I mentioned in my last post, their pregnancy is incredibly variable, lasting anywhere from 44-80 days, depending on the presence of warmth and food. [Feeling slightly smug in that Diddy's pregnancy was around 48 days! - She came into care on the 29th January - it takes up to 3 days to ovulate and become fertilised once awake from hibernation, meaning that she probably became pregnant around the 1st of February. We think she gave birth on the 20th March - a 48 day pregnancy!]
They are, of course, mammals – which means that they feed their young on milk. Studies have shown that mother bats need LOTS of water to do this – drinking as much as 13 times more water than female bats with no young!! Their nipples are located in their ‘armpit’, under the wing – presumably this makes flying easier for mum, makes hanging on easier for pup, and generally is pretty darn cozy!
Bats only have two nipples, unlike other small mammals such as shrews or mice – there is a theory that the number of nipples a mammal has is two times the average number of offspring, which for bats would be correct! (Horseshoe bats have a 2nd pair of false nipples in their groin area, which pups use to hang onto – they don’t produce milk, but they do mean that while mum is hanging upside down, baby is right-side up which you can see is the case with the bat on the right in the photo above!)
Check out this fantastic article about bat reproduction by the University of Nottingham.
I also found this fantastic poem about bat motherhood, and thought I’d share it with you! – Morgan x
By Randall Jarrell
A bat is born
Naked and blind and pale
His mother makes a pocket of her tail
And catches him. He clings
to her long fur
By his thumbs and toes and teeth.
And then the mother dances through the night
Doubling and looping,
Her baby hangs on
All night, in happiness,
She hunts and flies.
Her high sharp cries
Like shining needlepoints of sound
Go out into the night and
Tell her what they have touched.
She hears how far it is,
how big it is,
which way it’s going:
She lives by hearing.
The mother eats the moths and gnats
In full flight, In full flight.
The mother drinks the water of the pond,
She skims across,
Her baby hangs on tight.
Her baby drinks the milk she makes him.
In moonlight or starlight,
Their single shadow,
printed on the moon
Or fluttering across the stars,
Whirls on all night.
the tired mother flaps home to her rafter
The others all are there.
They hang themselves up by their toes,
They wrap themselves in their brown wings.
Bunched upside down, they sleep in air.
Their sharp ears,
Their sharp teeth
Their quick sharp faces
Are dull and slow and mild.
All the bright day, as the mother sleeps,
She folds her wings about her sleeping child.