Super Soaker! Spitting Fish Target Prey with Amazing Aim
by: Stephanie Pappas
Asia’s zebra-striped archerfish “shoot” their prey with streams of water that they use as a tool, a new study finds. Archerfish aren’t the only fish that use tools; the Pacific orange-dotted tuskfish uses rocks to crush clamshells. But archerfish are the only fish known to use adjustable jets of water as tools, according to the new study, published today (Sept. 4) in the journal Current Biology.
The fish can shoot land-based prey — including insects, spiders and even lizards — off of leaves and branches and into the water from a distance of up to 6.5 feet (2 meters) away. Previous research had found that the fish gather the water between the tongue and the roof of the mouth, forming a gun-barrel-like shape before spitting it out in powerful streams. In the new study, the researchers found that the fish modulate these jets so that the water is focused into a powerful point before impact — a talent that would seem to require a lot of brainpower.
The RoboTuna’s latest iteration comes by way of MIT, and cloaked in soft teal silicone. The fish, which keeps all of its computation and sensors in its head, contains a carbon dioxide canister that puffs pockets of gas to different parts of the body, making it undulate. It can also do something called a C-turn, an escape mechanism real fish pull off to avoid predators.
Two tiny gobies, no bigger than an inch, spotted on a dive near Marsa Alam, Egypt. A fleeting encounter of two translucent goby fish won the top prize at the 2011 Annual Underwater Photography Contest, hosted by the University of Miami.
Species in the Rhinochimaera family are known as long-nosed chimaeras. Their unusually long snouts (compared to other chimaeras) have sensory nerves that allow the fish to find food. Also, their first dorsal fin contains a mildly venomous spine that is used defensively. They are found in deep, temperate and tropical waters between 200 to 2,000 m in depth, and can grow to be up to 140 cm (4.5 ft) in length.
Chimaeras (also known as ghost sharks and ratfish) are an order of cartilaginous fish most closely related to sharks, but they have been evolutionarily isolated from them for over 400 million years.
(Info from WP and .gif from video by NOAA’s Okeanos Explorer—this is not an animation!)
Mudskipper is a fish which spend more time on land than in water. In fact, a mudskipper will drown if it’s never able to reach the water’s surface! Like other fish, mudskippers breathe through gills, but in addition they absorb oxygen through their skin and the linings of their mouths and throats. They are able to move over land by using their pectoral fins to pull themselves forward, or they perform a series of skips or jumps. Pokemon “Mudkip” is based on this fish.
Pictured above is a very peculiar fish that lives in a few North American caves. It looks very much like other fish, except in one respect: it has no eyes. The story of its adaptation to life in pitch blackness is one of the weirdest stories in evolutionary history.
Mutations vs. Cryptic Variation:
When people think about how evolution occurs, the classical model generally comes to mind. According to this view, species experience random genetic mutations that confer novel traits when they move to a new environment. The most beneficial traits — those that help individuals better adapt to their new habitat — get passed along to subsequent generations and eventually spread throughout the population.
It’s a relatively simple, easy-to-digest model, but it’s not able to explain all cases of evolution. “Imagine if you had a quick change in the environment,” said Nicolas Rohner, a geneticist at Harvard Medical School in Boston, Massachusetts. “This evolutionary process would take too long.” To rapidly adapt to a sudden shift in environment, a population would have to have some kind of standing genetic variation already available, which nature then selects for.
But how can this “cryptic variation” be maintained and accumulate in a species without actually affecting individuals before the environmental shift occurs? Scientists proposed that something must keep the genetic variation silent under normal conditions; then, when a species relocates to a new, life-threatening environment, it becomes physiologically stressed and that silencing mechanism stops or breaks down somehow…
It’s rough living in the deep sea. It’s super cold, rather scary, and absolutely pitch black. Luckily for the Flashlight Fish (Photoblepharon palpebratus) they never have to worry about the latter. Flashlight fish are aptly named for their large bean-shaped bioluminescent organs (a.k.a. photophores) under their eyes. To get that rockin’ glowing effect, luminous bacteria actually live in the organ create the light! It’s a symbiotic relationship in that the photophores glow in the dark, attracting zooplankton and small fish, on which the flashlight fish feed and the bacteria get the leftovers, so to speak. The light is also used for predator avoidance and for communication.