This lifeform is very common in suitable environments.

Black Tip Shark, Carcharhinus limbatus, is a small species that  rarely exceeds six feet in length. The Black Tip is found throughout most of the Atlantic Ocean and the New World Pacific, and possibly the Indian Ocean. This is a rather common shark.

Requim Sharks (Carcharinidae) contain the common sharks with which most people are familiar. This is a large family containing many species in the genus Carcharhinus. Most species in this group are less than ten feet in length. Only some are dangerous to man. Whaler Sharks of Australia have a bad, but well-earned, reputation. Following are some of the better known species in this family:

   Bronze Whaler    Carcharhinus ahenea        Australia
   Bignose Shark    Carcharhinus altimus       West N. Atlantic
   Blacknose Shark  Carcharhinus acronotus     Tropical Atlantic
   Spinner Shark    Carcharhinus brevipinna    Worldwide warmer
   Silky Shark      Carcharhinus falciformis   Near Florida
   S. Austrl whaler Carcharhinus grevi         Australia
   Finetooth Shark  Carcharhinus isodon        Atlantic Ocean
   Bull Shark       Carcharhinus leucas        Worldwide
   Blacktip Shark   Carcharhinus limbatus      Atlantic warmer
   Whitetip Shark   Carcharhinus longimanus    Tropical Worldwide
   Spinner Shark    Carcharhinus maculipinnis  Worldwide
   Black Whaler     Carcharhinus macrurus      Australia
   Sandbar Shark    Carcharhinus milberti      Atlantic
   Dusky Shark      Carcharhinus obscurus      Worldwide Tropical
   Reef Shark       Carcharhinus perezi        Atlantic Ocean
   Sandbar Shark    Carcharhinus plumbeus      Worldwide
   Smalltail Shark  Carcharhinus porosus       Tropical Atlantic
   Narrowtooth      Carcharhinus remotus       Worldwide
   Night Shark      Carcharhinus signatus      Atlantic Ocean
   Springer Shark   Carcharhinus springeri     Caribbean
   River Shark      Carcharhinus zambezensis   South Africa
   Tiger Shark      Galeocerdo cuvieri         Tropical Seas
   Soupfin Shark    Galeorhinus zyopterus      Eastern Pacific
   School Shark     Galeorhinus australis      Australia
   Lemon Shark      Negaprion brevirostris     Warm Oceans
   Blue Shark       Prionace glauca            Worldwide
   Sharpnose Shark  Rhizoprionodon terraenovae Atlantic Ocean

True Shark group (Order Lamniformes) contains the majority of the world's species of living sharks. They are characterized by  having five gill slits. Some taxonomists recognize over fifteen families in this order.

Sharks and rays (Elasmobranchi), cartilaginous fishes, deserve to be a class separate from the normal fish, in that they do not have a bone skeleton but rather a cartilage skeleton.

Fertilization is internal in this class which also separates them from the bony fish class. Although there are a few fresh water species, the majority of the species in this class are found in salt water. As of 2005, there were about 500 known species of sharks and about 600 known species of rays.

David Ebert, author of a recent book on sharks, rays, and chimaeras of California, counts a total of 988 described species in the class with about 150 additional species awaiting scientific description. He breaks down the described species to 410 species of sharks, 543 species of rays, and 35 species of chimaeras.

Backboned Animals (Phylum Chordata) are the most advanced group of animals on earth. These animals are characterized by having a spinal cord or backbone. Most members have a clearly defined brain that controls the organism through a spinal cord. Fish, amphibians, reptiles, birds, and mammals are in this phylum.

Currently, some taxonomists believe that the fish should be divided into two groups (sharks and regular fishes) and that there are some other primitive groups in the phylum such as hagfish or lampreys.

Animal Kingdom contains numerous organisms that feed on other animals or plants. Included in the animal kingdom are the lower marine invertebrates such as sponges and corals, the jointed legged animals such as insects and spiders, and the backboned animals such as fish, amphibians, reptiles, birds, and mammals.