Blacktip reef shark
The chondrichthians, or cartilaginous fishes, are an ancient class of animal that includes both the sharks and the rays. Fossil finds date back three times as far into prehistory as dinosaur evidence – and one hundred times as far as human evolution.
Today there are about 350 living species of shark divided into eight orders of thirty families.
The blacktip sharks belong to the order of CARCHARHINIFORMES, whose distinguishing features are five gill slits on each side of the head, two spineless dorsal fins, an elongated snout, a mouth ending behind the eyes, nicitating membranes (third eyelids), and the absence of enlarged molars in the last row of teeth.
This is also the largest order of sharks represented by 197 species. The CARCHARHINIFORMES can be found from the temperate zones to the tropics and the deep sea.
This order also includes most sharks potentially dangerous to humans.
Some other members are the small cat sharks and the weasel sharks, but also the maneaters and hammerheads.
The blacktip shark is a member of one of the forty eight species of the maneater family known for their attacks on humans.
Measuring 1.5 metres in length the relatively small blacktip has been known to attack humans on some occasions, but normally this behaviour is aggravated by blood in the water or the search for food. For instance, there have been several reports from harpooners of frenzied blacktip sharks’ snatching harpooned catches from their very hands.
The blacktip shark is a typical dweller of reef flats, elevated structures that separate the forereef from a lagoon and can even lie out of the water at ebb tide. During these times the blacktip shark keeps close to both sides of the reef flat at depths seldom greater than fifteen metres, a terrain it often shares with the grey reef shark.
At high tide it returns to shallow waters above all at night to feed. Very often its large dorsal fin juts right out of the water.
The blacktip shark is known to be extremely agile. Here too at ZOO-AQUARIUM visitors can witness its sudden manoeuvring. Especially when the glass panes are cleaned from the inside, the keeper in his diving suit always feels a chill run down his spine when the sharks first make straight for him before suddenly turning away from immediate collision at speeds of up to 30 km/h.
Particularly the gregarious tropical blacktips are accustomed to rest or even sleep in caves or beneath overhangs mostly during the day.
During these times cleaner fish and crabs get down to cleaning its scales. Because this shark does not have movable gill covers it slows down its respiratory rate and cardiac activity so that it does not have to swim to filter the oxygen it needs from the water.
Like mammals, maneaters give birth to live young that are provided with nutrients via a placenta in the uterus. Depending on the species gestation can take up to twelve months.