This is a fish that lives primarily on land.
They use water bubbles like a tongue to catch prey,
they shovel mud with their mouths and they have some seriously epic and floppy battles.
This is one of the most fascinating and weirdest animals in the world,
and one that sheds light on our own evolution.
This is the mudskipper.
Hi, I'm Danielle Dufault and you're watching Animalogic.
Let me tell you a true fish out of water story about a fish who doesn't particularly like water.
The mudskipper.
Mudskippers are amphibious fish found extensively from Africa to Australia.
For a while, they were considered to be in the goby family, and you can see why,
they have the same torpedo-shaped body and wide face.
Though recent studies have shown that they're in their own family.
Some species, like the giant mudskipper, can be up to 30 centimetres long,
but most species measure about 10 centimetres long.
Mudskippers live in swamps, estuaries, and other intertidal ecosystems.
But while most other fish there are active during high tide, mudskippers dine when the tide is low.
Also unlike other fish, they hunt on land.
Their entire strategy consists of walking
or skipping in the mud looking for insects or other small animals to eat.
Of course, this requires a specialized breathing system.
Similar to frogs, mudskippers can take oxygen from the air
through their skin and the soft tissue in their mouths and throats.
This is called cutaneous respiration.
The only caveat is that they must be wet for it to work.
They're like reverse gremlins and their permanent need for moisture
is the only reason they haven't taken over the world.
This is why they like mud so much.
They need frequent access to water which they get from the tidal pools formed in the mud.
Besides breathing through their skin, they also keep oxygenated water and air in their gills.
This is used as a backup in case they start drying out.
Walking on land requires a completely different form of locomotion.
Thankfully, mudskippers have muscular pectoral fins.
For these guys, it's "water's out, guns out."
The joint between the radials and the fin rays is functionally an elbow.
The radial also connects to the body at an
articulated joint that is basically their shoulder.
All of this is supported by powerful muscles that make them great at push-ups and skipping around.
They can move one fin at a time, like we walk,
or they can move them forward at the same time, in a move called "crutching."
Some species can even climb branches and tree trunks,
using their concave hip bones as a sort of sucker for extra grip.
Being terrestrial hunters, they need good eyesight to find their prey.
Their eyes have evolved to work better outside of the water than in it.
The eyes sit at the top of the head.
They can move independently and with a huge range of motion,
giving them almost a 360 degree field of vision.
Their only problem is that they only work well when moist.
To deal with this problem, their eyes can retract into a water sack beneath their eyes.
This looks like they're blinking but it's
a bit more elaborate than our version of moistening our eyes.
One of the spookiest things a mud skipper can see, other than a predator, is another mudskipper.
They can be cannibalistic.
Hey, we never said they were chillers.
In order to intimidate each other, protect their territories,
and dissuade sexual rivals, they do what most terrestrial animals do.
They yell.
The only issue is that they don't have ears and detect vibrations through their body instead.
So when they yell at each other they yell in low frequencies which can be hard for us to hear,
but easier for them to pick up through their bones.
When the tide is high they hide in burrows for their protection.
Their little fins are great for hopping around in the mud, but not so great for swimming.
In order to build these burrows, they use their mouths as a wheelbarrow - gulping back mud,
carrying it to the surface and spitting it out.
Repeat enough times and you have yourself a burrow - and a dire need for mouthwash.
To protect themselves from predators, they will usually build in twists and turns,
which makes it hard for predators to snatch them out of their burrows.
Since the water stuck in their burrows usually becomes oxygen-deficient within a few hours,
they bring in air bubbles in their mouth as a little backup oxygen tank.
So smart.
Their ability to build well-engineered burrows is crucial to their survival
as it ensures not only their immediate survival, but also their ability to reproduce.
During the mating season males fight each other and perform elaborate displays to woo the females.
And these fights are epic, floppy, muddy messes.
It is a delight to behold.
Males also change colours, becoming brighter,
and their throats get very shiny and in some species it changes colours too.
During displays they push themselves up and show off their beautiful throats.
Who doesn't love a good throat?
This is called flagging and it's a good indicator for health.
Healthier males will have brighter throats.
Females will choose their favourite healthy male and follow them to their burrow.
They lay the eggs and stick them to the walls of the burrow, and then the male fertilizes them.
Soon after that, the female leaves, and the male
is in charge of protecting the eggs until they hatch.
When they're not in their burrows, they're likely out hunting.
Though they don't seem like the most menacing of predators,
they have adapted to catch their prey basically by water-bending.
Atlantic mudskippers carry water in their big mouths.
When they're within range of a potential prey
they spit some of that water on the prey and then quickly suck it back in.
This is done so quickly that the prey ends up being sucked into the mouth along with the water.
In effect they have turned water into their own version of a sticky tongue.
This helps them catch a huge array of prey from worms, to flies, to crickets, to crabs.
Imagine being a crustacean and being eaten by a fish out of the water.
Oh, how the turntables.
This process of gradually getting out of the water is similar to what our
latest fish ancestors did before becoming fully terrestrial and becoming tetrapods.
Like mudskippers, they likely lived in intertidal environments
and gradually became able to spend more and more time out of the water.
So what should we talk about next?
Please let me know in the comments and be sure to subscribe for new episodes every week.
Thanks for watching, see ya.
Yes, exactly.
They all...
Oh my god, they would all make Arnold sounds.
That's, that's my head cannon now.
I'm screaming.