Ilove them. I mean, look at their big, shiny eyes! NO ONE can say that they aren’t cute as hell!
Theotherreason I love these animals is because they’re basically what happens when evolution tries to make a bat out of a bird.
These little guys are known as oilbirds (Steatornis caripensis), and are also called guácharo (and also several other things, because they are found in South America, plus Trinidad & Tobago, which all have INCREDIBLE language diversity).
Oilbirds are nocturnal, flying around the forests of South America at night looking for fruit to eat. They also live colonially in caves, which they navigate using echolocation.
So, to review:
(I’m making my Generic Bats a verygeneric fruit bat, for the record).
Oilbirds are the only birds with this combination of traits, which I think is pretty cool of them! Why are they so much like bats? Basically, when different types of animals evolve under similar selective pressures, they often evolve the same features! This is called convergent evolution, and wowI talk about it a lot on this blog! It turns out that nocturnal animals that live in caves and eat fruit can sometimes benefit from traits like these!
(they’re, like… spooky-cute. Cute-spooky? Either way, I like them a lot)
So, if these birds are flying around at night, how do they stop themselves from flying into things while searching for that tasty, tasty fruit?
Well, in the forest, they mostly rely on their AMAZING night vision (which is another trait they share with bats, fyi). That is why they have such big, adorable eyes, which has a lot of light-sensing cells called rods. They actually hold a record for the density of the rods in their eyes: one million per square millimetre. That is the highest density of any known vertebrate. It’s about 6x denser than the rods found in human eyes!
Their amazing vision allows them to see verywell in low light, which is how they navigate the South American jungles at night, searching for food under the moon and stars. That said, their vision just doesn’t cut it when it comes to flying in the caves they call home. Why? Well, caves are dark as hell, and even the best night-vision can’t do anything for you when there’s no light at all. Plus, flying into cave walls/ cliff faces hurts, so it’s good to be extrasure you’re not flying into solid rock!
Sohowdo they find their way around these dark caves? Well, they use something veryunusual for birds: echolocation!
Oilbirds are one of only a few species of birds that are known to use echolocation (the others are a few species of the closely-related swiflets (Collocaliini), but I HAVE DECIDED TODAY IS FOR THE OILBIRDS im sorry, swiflets, ilu2).
Look at them, not flying into rocks! I’m so proud (˃̣̣̥ ◡ ˂̣̣̥)
Also, a bonus fact, because idk where to fit this but I MUST mention it:
They have little whiskers around their beaks (which are technically called “rictal bristles”, but I’m going to call them “whiskers” because I like that word better). These whiskers are basically used to feel things that they have in and around their mouth, helping them find, manipulate, and eat their tasty fruit!
