The Pike and the Sazan

Scientists have described up to 20,000 different species of fish which are living today. Many have been found fossilized - they have lived on our planet but have become extinct.

Some fish inhabit fresh-water rivers and lakes; others prefer the salt water of the seas and oceans. There are fish which keep close to the bottom; others swim nearer the surface. Some are vegetarians adding to their diet slow-moving animals; others catch swiftly swimming prey.

Their different ways of living influence their anatomy. You will notice these differences if you study the general characteristics of a few different species.

The Pike is long and slender and has a big head narrowed at the tip. The Sazan is broad and thick with a small head. The Pike has an enormous mouth equipped with rows of formidable-locking teeth curved backwards. Because of their teeth, pikes should be handled very cautiously even when caught on a fishing line. The Sazan, on the other hand, has a small mouth and teeth.

Why is the difference so great? The explanation is to be found in their diets.

The Pike is carnivorous. It eats fish. You can see it sometimes, motionless among the weeds. As soon as fish along the Pike darts forwards like an arrow, its mouth wide. Pikes have been known to attack ducklings, water rats and other animals. The powerful tail near the soft dorsal fin and the anal fin are attached, as well as the long slender body, help the Pike to swim swiftly in pursuit of its prey. The sharp teeth curved backwards hold the victim so that even the slime covering its body does not help.

The Pike's colour pattern facilitates the pursuit of its greedy and destructive habits, it can easy conceal itself. It is mottled green, with dark bands and difficult to distinguish from the weeds among which it hides when waiting for its prey. The Sazan has different habits. It does not hunt other fish but feeds on a mixed diet of insect larvae, mollusks, worms and even vegetable matter. The Sazan locates its food in the river mud and silt by means of two sensitive feelers on its upper lip. The mouth is small and there are no teeth. There are no need of them. Down in its pharynx are several blunt teeth used to crush the shells of mollusks and grind vegetation.

The shape of the Sazan's body is also different from that of the agile Pike. It is taller and thicker and the tail is rather weak. The peculiarities in anatomy and habits are due to the fact that their ancestors did not live in identical environments. They ate different food and developed their own methods of obtaining it.

Vocabulary:

Pike- щука

Fossilize- закам'яніти

Vegetarian- вегетаріанець

Prey- здобича

Formidable- грозний

Carnivorous- хижий

In pursuit of- в погоні за

Curved backwaters- загнуті назад

Mottled green- в зелених плямах

Larvae- личинки

Feeler- щупальце

Pharynx- глотка

Shell- мушля, черепашка

Ancestor- пращур