Under Water Archer
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
Perciformes
Family:
Toxotidae
Genus:
Toxotes
Species:
jaculatrix
Author: Cuvier, 1816
Fishes forage for food
in various ways and the way it forages it depends on the environment,
physiology, morphology. Here, there is a fish that uses water as arrow to catch
its prey. Archer fish is distributed in estuaries, mangrove swamps and river
mouths of Indo-pacific waters. It posses laterally compressed body with five
black markings on either sides. Unlike other fishes the dorsal fins present at
the posterior end of the body. Juveniles grow in fresh water and move to
brackish and then to sea when as it become adult. Mouth is protractible with
groove in upper end that helps in ejecting water to catch its prey. This fish
can grow up to 30 cm in length. Archer fish feeds on land based insects such as
spider, grasshopper, butter fly etc.
Speciality
of Predation
Every fish has their
own way of predating their prey; Archer also follows its own way for predation.
It spits water as arrow to catch the prey present above the surface of water.
Strategy behind this is, when it sees the prey it roles its eye to get a full
image of the prey on ventral temporal periphery of retina and spits the water
by placing tongue at groove present in upper end of mouth. It acts as a tube
through which the water passes in jet speed by compressing operculum. It
usually shoots at an angle of 74 degree but, the aim is accurate at 45 and 110
degree. Accuracy is not only because of having good eyesight, it also knows to
compensate refraction of light that passes air sea interface during aiming.
Italian scientists demonstrated the force of the water is based on water
dynamics rather than using internal muscles. It modulates the velocity of the
jet as it alters its shape through air. The top of the jet increases in volume
as it gets liquid from tail to form a big drop that hits insects with greater
force. Adults almost hit the prey in a
single shot but, juveniles’ accuracy increases as it gets adult. Hence,
juveniles hunt in groups to catch their prey.
Acknowledgement
Every fish has their
own way of predating their prey; Archer also follows its own way for predation.
It spits water as arrow to catch the prey present above the surface of water.
Strategy behind this is, when it sees the prey it roles its eye to get a full
image of the prey on ventral temporal periphery of retina and spits the water
by placing tongue at groove present in upper end of mouth. It acts as a tube
through which the water passes in jet speed by compressing operculum. It
usually shoots at an angle of 74 degree but, the aim is accurate at 45 and 110
degree. Accuracy is not only because of having good eyesight, it also knows to
compensate refraction of light that passes air sea interface during aiming.
Italian scientists demonstrated the force of the water is based on water
dynamics rather than using internal muscles. It modulates the velocity of the
jet as it alters its shape through air. The top of the jet increases in volume
as it gets liquid from tail to form a big drop that hits insects with greater
force. Adults almost hit the prey in a
single shot but, juveniles’ accuracy increases as it gets adult. Hence,
juveniles hunt in groups to catch their prey.Acknowledgement
Pictures and video were collected from following
links
http://ies.franciscoasorey.ccmc.climantica.org/2012/10/28/un-chorro-mortal/